A new map of the mountains, valleys and canyons hidden under Antarctica's ice has revealed the deepest land on Earth, and will help forecast future ice loss.

The frozen southern continent can look pretty flat and featureless from above. But beneath the ice pack that's accumulated over the eons, there's an ancient continent, as textured as any other. And that texture turns out to be very important for predicting how and when ice will flow and which regions of ice are most vulnerable in a warming world. The new NASA map, called BedMachine Antarctica, mixes ice movement measurements, seismic measurements, radar and other data points to create the most detailed picture yet of Antarctica's hidden features.

Related: 50 Amazing Facts About Antarctica

"Using BedMachine to zoom into particular sectors of Antarctica, you find essential details, such as bumps and hollows beneath the ice that may accelerate, slow down or even stop the retreat of glaciers," Mathieu Morlighem, an Earth system scientist at the University of California, Irvine and the lead author of a new paper about the map, said in a statement.

The new map, published Dec. 12 in the journal Nature Geoscience, reveals previously unknown topographical features that shape ice flow on the frozen continent.

The previously unknown features have "major implications for glacier response to climate change," the authors wrote. "For example, glaciers flowing across the Transantarctic Mountains are protected by broad, stabilizing ridges."

Understanding how ice flows in Antarctica becomes increasingly important as Earth warms. If all of Antarctica's ice were to melt, it would raise global sea levels by 200 feet (60 meters), according to the National Snow and Ice Data Center. That isn't likely anytime soon, but even if small fractions of the continent were to melt, it would have devastating global effects. 

Included in the data is evidence for the deepest canyon on planet Earth. By studying how much ice flows through a particular, narrow region known as the Denman trough each year, the researchers realized it must dive at least 11,000 feet (3,500 meters) below sea level to accommodate all the frozen water volume. That's far deeper than the Dead Sea, the lowest exposed region of land, which sits 432 meters (1,419 feet) below sea level, according to the Israel Oceanographic and Limnological Research center.

The map offers a wealth of new information on precisely which regions of the continent's ice are at most risk of sliding into the ocean in the coming decades and centuries, the authors wrote.

• Images of Melt: Earth's Vanishing Ice
• In Photos: Antarctica's Larsen C Ice Shelf Through Time
• Icy Images: Antarctica Will Amaze You in Incredible Aerial Views

Originally published on Live Science.

A new map of Antarctica's surface is so detailed, it almost seems as though if you put your hand on it you could trace the bumps in the ice ridges curving up the Antarctic Peninsula.  

Researchers compiled the stunning topographic map from high-resolution photos that were collected over six years by a group of satellites orbiting hundreds of miles above Earth. To create the map, millions of images were processed by one of the world's largest supercomputers, called the Reference Elevation Model of Antarctica (REMA), according to a statement released by the University of Minnesota.

Earlier maps of the icy continent were produced at a resolution of more than 3,000 feet (1,000 meters), but the new map delivers an astonishing resolution of about 26 feet (8 m) and covering 5.4 million square miles (14 million square kilometers), making it the most accurate map of Antarctica to date. [Images of Melt: Earth's Vanishing Ice]

"Up until now, we've had a better map of Mars than we've had of Antarctica," Ian Howat, one of the researchers with the project and director of the Byrd Polar and Climate Research Center at The Ohio State University, said in the statement.

"Now it is the best-mapped continent on Earth," Howat said.

The height of every icy bluff and rocky outcrop on Antarctica is now easily within scientists' reach, and is accurate to within just a few feet, according to the statement. 

"At this resolution, you can see almost everything," Howat said. "We will see changes in snow cover, changes in the motion of ice, we will be able to monitor river discharge, flooding and volcanoes. We will be able to see the thinning of glaciers."

With the data in hand — and there's quite a lot of it, as the map file is 150 terabytes — scientists will now be able to better visualize the impact of a warming world on Antarctica's landscape, Morin said in the statement.

"Now, we'll be able to see changes in melting and deposition of ice better than ever before," he said. "That will help us understand the impact of climate change and sea level rise. We'll be able to see it right before our eyes."

The map was published online Sept. 4 by the Polar Geospatial Center at the University of Minnesota.

Original article on Live Science.

To showcase NASA's accomplishments on artificially intelligent navigation, the agency invited professional drone racer Ken Loo to go toe-to-toe with their software.

The race on Oct. 12 followed two years of AI research by NASA's Jet Propulsion Laboratory (JPL), in Pasadena, Calif. JPL's success in spacecraft navigation attracted Google, who funded the research on drone autonomy, NASA said in the statement accompanying a video they released on Tuesday (Nov. 21).

JPL built three quadcopter drones — nicknamed Batman, Joker and Nightwing — to test the new software. The algorithms use two cameras mounted on each drone and compare what they see with a pre-loaded map of the area. The program also takes advantage of Google Tango, an augmented reality technology the company developed to use vision to allow a device to determine its position and location. [10 Ways Robots Move on Mars]

The team set up an obstacle course in one of JPL's warehouses to put the software to the test. "We pitted our algorithms against a human, who flies a lot more by feel," Rob Reid, the project's task manager, said in the statement.

The two pilots began with similar lap times. However, Loo was able to learn the course after many laps. He achieved higher top speeds with impressive aerial maneuvers, cutting down his overall times. In contrast, the AI took the course more cautiously, but more consistently as well. "The AI was able to fly the same racing line every lap," NASA said.

The pilots also faced unique challenges. Sometimes, the race-ready drones moved so fast that the cameras couldn't properly focus, which disoriented the computer flying them. But as the day wore on, Loo had to battle fatigue, a problem the AI pilot needn't worry about. You'll have to watch the video to see who won the race.

Most autonomous drones use GPS to navigate. But this won't work for indoor spaces and crowded urban environments — hence the efforts to develop alternative forms of computer navigation. These technologies may find use in warehouses, roads, and disaster sites, Reid said.

Email Harrison Tasoff at htasoff@space.com or follow him @harrisontasoff. Follow us @Spacedotcom, Facebook and Google+. Original article on Space.com.

In the Amazon rainforests that are home to hundreds of known species of monkeys — and likely more that have yet to be discovered — it can be extremely difficult for conservationists to track their numbers and monitor how they are affected by human activities such as hunting and deforestation.

However, scientists proposed in a recent study that a diverse range of technologies, including satellites, can combine with observations on the ground to give a more accurate picture of biodiversity among monkeys and other animals in hard-to-access habitats.

Most satellites can't directly detect the activities and numbers of small animals living in dense forests. But together with DNA evidence, field reports, and audio and visual records, they could help researchers identify monkey populations that are declining or at risk, the study authors reported. [25 Strangest Sights on Google Earth]

Scientists typically approximate the presence and number of monkeys in a given area though first-hand observations and recordings, such as those obtained by camera traps. But other indirect sources can also provide clues about animals in a habitat — DNA extracted from feces, urine or saliva can hint at local diversity, and so can blood ingested by mosquitoes, according to the study.

These DNA-based methods provide another missing piece of the biodiversity puzzle, but observations from the sky can also determine whether certain animal populations have declined over time, the researchers wrote.

In forests, tree species that take up more of the greenhouse gas carbon dioxide (which they use for photosynthesis) than other trees typically produce larger seeds. Those seeds are primarily dispersed by monkeys. Satellite data could show whether regions where human activity is high and monkeys are exposed to hunting — and where their numbers may have been dropping — correspond to forests where there are fewer of these high-carbon-density tree species; the primary seed disperser would not be available to spread these species, the researchers speculated.

"In short, by combining Earth-observation-derived maps of human activity with empirical observations of the response of primate populations to that activity, it should be possible to map and track an ecosystem function (large-seed dispersal) that is invisible to satellites but contributes to an important ecosystem service (climate regulation)," the study authors wrote.

These methods can be applied not only to monkey populations, but to a variety of wildlife, the researchers explained.

"With the parallel developments in remote sensing, genomics and more automated field recording, we now have the tools needed to collect data at large scales," study lead author Alex Bush, a researcher with the Kunming Institute of Zoology at the Chinese Academy of Sciences, said in a statement.

The findings were published online June 22 in the journal Nature Ecology and Evolution.

Original article on Live Science.

With today’s historic and incredibly exciting announcement of the first ever detection of gravitational waves came the news that these waves were generated by two merging black holes approximately 1.3 billion light-years away — an astrophysical event that is mind-blowing in its own right. So the next question that comes to mind is, unsurprisingly, in which direction did this black hole merger occur?

As it turns out, scientists of the Laser Interferometer Gravitational-Wave Observatory (LIGO) already have an answer, albeit a very general one.

ANALYSIS: We Just Heard the Spacetime 'Chirp' of Black Hole Rebirth

As previously reported, LIGO is composed of two stations — one in Washington and the other nearly 2,000 miles away in Louisiana. The reason for having 2 stations is logical: should a gravitational wave pass through our volume of space (yes, these spacetime ripples pass through the Earth and us unimpeded), it must be detected by both stations to be confirmed as being “real” and not a false positive caused by some kind of local disturbance near one of the stations. Secondly, having 2 stations allows LIGO scientists to triangulate the signal to derive a very general idea as to where these waves are coming from.

Thursday’s grand announcement pointed out that the Livingston station (Louisiana) “heard” the gravitational wave "chirp" 7 milliseconds before the Hanford station (Washington) on Sept. 14, 2015. As gravitational waves travel at the speed of light, this timing difference confirmed that the two detections were indeed the same event. Scientists were immediately able to deduce the direction the gravitational waves were traveling.

NEWS: Gravitational Waves Detected for First Time

Now, the LIGO collaboration has released a map of the Southern Hemisphere skies, giving us a glimpse at the promising future of gravitational wave astronomy. In the map, contours have been added that represent the different probabilities for where the signal originated. The outermost purple line represents a 90 percent certainty that the signal’s source (the colliding black holes) is contained within that area. The innermost white contour line highlights a possible source region to a 10 percent certainty.

The band of stars through the middle of the image is the edge-on disk of the Milky Way and the Large Magellanic Cloud and Small Magellanic Cloud (two small nearby galaxies) can also be seen in the bottom portion of the image. It is worth noting that, although there is some uncertainty in the black hole’s distance, its location is far beyond our own galaxy and Local Group of galaxies.

EXPLAINER: What You Need to Know About Gravitational Waves

As more gravitational wave detectors go online and their observations added to LIGO’s detections, better precision of the locations of gravitational wave sources will be pinpointed, making for highly detailed gravitational wave maps of the cosmos. So though it may not be precise, this is the first map of its kind where inside its contours two black holes merged 1.3 billion years ago.

Source: Caltech

This article was provided by Discovery News.

Snow globes, those favorite vacation souvenirs, let even those who live in warm climates see snow fall. From their vantage point in space, NASA satellites get to see a real snow globe, as they observe the seasonal falls that cover portions of the planet with the white stuff.

A set of observations collected between February 2000 and November 2011 by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite has been stitched together to create an animation of Earth's snow cover over the past decade.

Areas in medium blue have a snow cover of more than zero percent and white areas are covered 100 percent, with other colors ranging in between. Land that appears gray either had no snow cover or was an area not covered by MODIS data. Because MODIS relies on visible light to assess snow cover, the sensor cannot collect data over the highest latitudes of the Northern Hemisphere during winter when no sunlight reaches those regions.

Snow and ice cover most of the Earth's polar regions throughout the year, but the coverage at lower latitudes depends on season and elevation. High-altitude landscapes such as the Tibetan Plateau and the Andes and Rocky Mountains maintain some amount of snow cover almost year round.

Land area is larger and snow cover is more variable in the Northern Hemisphere than in the Southern Hemisphere.

This article was provided by OurAmazingPlanet, a sister site of SPACE.com.

The first comprehensive set of maps of the slopes and craters on the lunar surface is revealing clues about the violent history of the moon.

Unlike on Earth, where wind and water frequently erode geological features, the moon's landscape is less volatile. Features from hundreds of millions, or even billions, of years ago are still visible.

Using the Lunar Orbiter Laser Altimeter (LOLA) on NASA's Lunar Reconnaissance Orbiter, scientists have developed a detailed map of the changes in the contours of the moon from pole to pole. Studying the roughness of these features reveals more about their age and their formation. [See the new moon map here]

Some events are sudden, such as the craters that formed when comets and asteroids crashed into the moon. Mapping the surface provides clues to the ages of the impact sites. The edges of older craters changed as more and more space rocks bombarded them, while newer ones have a sharper, more defined rim.

Other processes occurred gradually. The dark, smoother parts of the moon, known as maria, formed by volcanism.

"As maria age, they change in their roughness properties," researcher Oded Aharonson of California Institute of Technology told SPACE.com. Newer lava flows are smoother than their older counterparts. Aharonson and his colleagues, led by Margaret Rosenburg, also of Caltech, detailed their findings in a paper published in the Journal of Geophysical Research.

Even landslides can reveal activity from the lunar past. Moonquakes and impacts from large objects can cause loose material to slide downhill, or even break off part of a cliff. Examining the steepness of the rubble pile can give clues about the event that shifted it.

In addition to revealing hints about the lunar past, such detailed topography data can help locate potential sites for ice by revealing shaded, stable regions where water is likely to freeze. 

The moon isn't the only place such a detailed examination can come in handy. Other celestial bodies have received similar mapping, though none with quite as much detail as LOLA provides.

Mars, Earth, Venus and Saturn's moon, Titan, have all received some degree of examination, and the Mercury Laser Altimeter is currently scanning the planet closest to the sun. As long as the terrain isn't liquid or gas, it could provide valuable data.

"Understanding the surface roughness properties would be an interesting pursuit for any object with a solid surface in the solar system," Aharonson said.

Follow SPACE.com for the latest in space science and exploration news on Twitter @Spacedotcom and on Facebook.

This story was updated at 11:29 am ET.

BOSTON — Astronomers have created the most complete 3-D map of our local universe, revealing new details about our place in the cosmos.

The map shows all visible structures out to about 380 million light-years, which includes about 45,000 of our neighboring galaxies (the diameter of the Milky Way is about 100,000 light-years across). [See the new 3-D universe map image.]

"I think it speaks to our desire to understand our place in the universe," said Karen Masters of the University of Portsmouth in England, during a press conference today. "I wouldn’t be happy if we didn't have a complete map of the Earth. It's nice to have a complete map of where we live."

The map was assembled using data from the Two-Micron All-Sky Survey (2MASS) Redshift Survey (2MRS), which took 10 years to scan the complete night sky in near-infrared light. The survey used two ground-based telescopes, the Fred Lawrence Whipple Observatory on Mt. Hopkins, Ariz., and the Cerro Tololo Inter-American Observatory in Chile.

Near-infrared light, which is of a longer wavelength than visible light, can penetrate the opaque clouds of dust common in galaxies. This allowed the 2MRS survey to extend its "eyes" closer to the plane of the Milky Way galaxy than has been possible in previous studies, because that area is heavily obscured by dust.

"This covers 95 percent of the sky," Masters said. "In the infrared, we're less affected by the gunk in the milky way so we're able to see down closer to the plane of the galaxy." [Video: Seeing Dark Matter in 3-D]

Masters presented the new map here today at the 218th meeting of the American Astronomical Society.

The 3-D aspect of the map comes from the fact that researchers measured the cosmic objects' redshift, which denotes how much its light has been shifted toward the red end of the color spectrum. This happens because of the so-called Doppler effect, which causes the wavelength of light to be stretched when the light's source is moving away from us.

Because the universe is expanding, measuring an object's redshift, and hence its velocity, allows astronomers to deduce its distance, because objects that are farther away are moving more quickly.

In addition to providing a more complete picture of our place in the universe, the new map could help solve the perplexing mystery of why the Milky Way moves the way it does with respect to the rest of the universe. This motion, about 370 miles per second (600 km per second) has yet to be explained by the gravitational attraction of the known objects near our galaxy.

"The most important science question that having a complete map addresses is the source of the motion of the Milky Way," Masters said. "What's causing that is gravity, and finding the source of that gravity, where the mass is, has been a longstanding issue. Only by making an all-sky map can you account for all the galaxies that are there. We should now be able to account for that motion."

For example, one structure revealed for the first time in the new map is likely to exert a gravitational tug on the Milky Way and could be part of the solution, the researchers said.

You can follow SPACE.com Senior Writer Clara Moskowitz on Twitter @ClaraMoskowitz. Follow SPACE.com for the latest in space science and exploration news on Twitter @Spacedotcom and on Facebook.

This story was updated at 3:06 p.m. EDT.

In the murky boundary between our solar system and the restof the galaxy, scientists have spotted a bright band of surprising high-energyemissions.

The results come from the first all-sky map created byNASA's new InterstellarBoundary Explorer (IBEX) spacecraft, which launched in October 2008. Whileorbiting Earth, IBEX monitors incoming neutral atoms that originate billions ofmiles away at the solar system's edge to learn about the interaction betweenthe sun and the cold expanse of space.

"The IBEX results are truly remarkable, with emissionsnot resembling any of the current theories or models of this never-before-seenregion," said David McComas, IBEX principal investigator at the SouthwestResearch Institute in Texas. "We expected to see small, gradual spatialvariations at the interstellar boundary, some 10 billion miles away. However,IBEX is showing us a very narrow ribbon that is two to three times brighterthan anything else in the sky."

This ribbon of energy lies at the very edge of the solarsystem, where the bubble of charged particles streaming from the sun finally petersout. This bubble is called the heliosphere, and it encompasses the region ofspace dominated by the sun's influence.

The edge of the solar system

At the boundary of the heliosphere, the sun'spositively-charged particles interact with neutral atoms drifting in frominterstellar space. When these particles meet, an electron may hop over from a neutralatom to a charged one, called an ion. The result: the charged particle becomesneutral. IBEX detects these fast-moving neutral particles and traces their pathsback to the solarsystem's edge to create a picture of this chaotic frontier.

"We're just now getting a handle on the interaction ofthe surrounding interstellar medium with the heliosphere, and that's providingus with the big picture," said mission co-investigator Eberhard M?bius ofthe University of New Hampshire.

The mission scientists said they were surprised to discoverthe striking band in IBEX's sky maps, because no models had predicted such apattern beforehand.

McComas said when he first saw the IBEX results he thought,"'Something's wrong,' It was quite a long time before we convinced ourselvesthat we were right," he said.

The bright ribbon appears to be shaped by the direction ofthe interstellar magnetic field outside the heliosphere. Scientists think thissuggests that the galactic environment just outside the solar system has farmore influence on the structure of the heliosphere than previously believed.

"[The ribbon is] aligned by and dominated by theexternal magnetic field," McComas said in a briefing Thursday. "That'sa huge clue as to what's going on. But still we're missing some really fundamentalaspect of the interaction - some fundamental physics is missing from our understanding."

The boundary of the solar system was first explored by the Voyager1 spacecraft in 2004 when it encountered an invisible shock created as thecharged particles streamingoff the sun hit the neutral gas from interstellar space. Its sister craft Voyager2 followed into the solar system's edge in 2007. While these spacecraft beganthe exploration of this wild frontier, IBEX is now revealing a whole newpicture.

"The most astounding feature in the IBEX sky maps ? thebright narrow ribbon ? snakes through the sky between the Voyager spacecraft,where it remained completely undetected until now," McComas said.

The new IBEX results will be published in the Oct. 16 issueof the journal Science.

• Video - NASA?s IBEX: Exploring the Solar System?s Edge
• Images - Voyager's Photo Legacy
• Top 10 Voyager Facts

An aging but dependable NASAprobe has tweaked its orbit around Mars to seek out warmer ground on the distant,red world.

NASA reckons the infraredcameras aboard the Mars Odyssey spacecraft will work better over regionsexposed to more sunlight, so it shifted the probe?s orbit in order to steer itscamera eyes away from the evening shade. The move took nearly eight months, ,but Odyssey?s infrared camera now peers onto the planet during the Martianafternoon, earlier than it has during most of its seven-year mission.

"The orbiteris now overhead at about 3:45 in the afternoon instead of 5 p.m., so theground is warmer and there is more thermal energy for the camera's infraredsensors to detect," said Jeffrey Plaut planetary scientist at NASA's JetPropulsion Laboratory (JPL) in Pasadena, Calif., in a statement.

The orbital switch increasesthe sensitivity of the camera, called the ThermalEmission Imaging System, to allow for better mapping of Martian minerals.It now senses infrared radiation from a warmer surface that is receiving moresunlight.

A warmer Martian target

Temperatures on Mars rangefrom as low as minus 195 degrees Fahrenheit (-125 degrees Celsius) near thepoles during the winter to 70 degrees Fahrenheit (20 degrees Celsius) at noonnear the equator. The average Martian temperature is about? minus 80 degreesFahrenheit (-60 degrees Celsius).

On Sept. 30, 2008, Odysseyfired its thrusters for six minutes, entering into a "drift"pattern that gradually changed its orbit and the time-of-day during which itwas over the planet. On June 9 of this year, the spacecraft fired the thrustersagain, this time for 5.5 minutes. The burn ended the drift pattern and lockedthe spacecraft into the new orbit, always above the planet in themid-afternoon.

"The maneuver wentexactly as planned," said JPL's Gaylon McSmith, Odyssey mission manager.

Afternoons on Mars

This is not the first timethe orbiter will see a sunnier side of Mars. Back in 2002, early in Odyssey'smission, it flew mid-afternoon passes over the planet and made importantdiscoveries of minerals, including salt deposits that were apparently leftbehind by large bodies of water when they evaporated.

"The new orbit means we can now get the type of high-quality data for therest of Mars that we got for 10 or 20 percent of the planet during those earlysix months," said Philip Christensen, an Arizona State University researcher who is principal investigatorfor Odyssey's Thermal Emission Imaging System.

The trade-off is that thenew orbit will put one of the spacecraft's other instruments out of commission.The gamma-ray detector, one of a suite of three instruments that sense shortlight waves and neutrons, must be shut down or risk overheating. In 2002, thesuite, called the Gamma Ray Spectrometer, made a dramatic discovery of largeareas of water-ice near the Martian surface. The gamma ray detector has alsomapped the global deposits of many elements, such as iron, silicon andpotassium.

NASA launched the MarsOdyssey orbiter in 2001. The solar-powered spacecraft arrived at the red planetabout a year later to begin its now seven-year Mars observation campaign.

?       Video- Digging on Mars

?       Video- Will Odyssey Get a Definitive Answer on Mars Water?

?       SpecialReport: Odyssey Mission to Mars

People in the eastern United States will get a great opportunity, weather permitting, to see the Space Shuttle Discovery launched into orbit Wednesday evening.

The shuttle flight (STS-119) will be the 28th to rendezvous and dock with the International Space Station (ISS), and the glow of its engines will be visible along much of the Eastern Seaboard of the United States. A SPACE.com map shows the area of visibility.

To reach the ISS, Discovery must be launched when Earth's rotation carries the launch pad into the plane of the station's orbit. For mission STS-119, that will happen at 9:20:10 p.m. ET on Wednesday, resulting in NASA's second consecutive nighttime launch (the most recent coming on Nov. 14).

As has been the case with other launches to the ISS, this upcoming launch will bring the shuttle's path nearly parallel to the U.S. East Coast.

What to expect

In the Southeast United States, depending on a viewer's distance from Cape Canaveral, the "stack" (shuttle orbiter, external tank and solid rocket boosters) can be easily followed thanks to the fiery output of the solid rocket boosters.  The brilliant light emitted by the two solid rocket boosters will be visible for the first 2 minutes and 4 seconds of the launch out to a radius of some 520 statute miles from the Kennedy Space Center.

Depending on where you are located relative to Cape Canaveral, Discovery will become visible anywhere from a few seconds to just over 2 minutes after it leaves Pad 39-A.

For an example of what all this looks like from Florida, see video of a night launch made by Rob Haas from Titusville, FL, on Dec. 9, 2006 (the STS-116 mission).

After the solid rocket boosters are jettisoned, Discovery will be visible for most locations by virtue of the light emanating from its three main engines.  It should appear as a very bright, pulsating, fast-moving star, shining with a yellowish-orange glow. Based on previous night missions, the brightness should be at least equal to magnitude -2; rivaling Sirius, the brightest star in brilliance.  Observers who train binoculars on the shuttle should be able to see its tiny V-shaped contrail.

James E. Byrd shot video of the shuttle from Virginia after a November 2000 night launch. The bright star Sirius briefly streaks through the scene giving a sense of scale and brightness to the shuttle's glow.

For most viewers, the shuttle will appear to literally skim the horizon, so be sure there are no buildings or trees to obstruct your view. 

Depending upon your distance from the coastline, the shuttle will be relatively low on the horizon (5 to 15 degrees; your fist on an outstretched arm covers about 10 degrees of sky).  If you're positioned near the edge of a viewing circle, the shuttle will barely come above the horizon and could be obscured by low clouds or haze.

If the weather is clear the shuttle should be easy to see. It will appear to move very fast; much faster than an orbiting satellite due to its near orbital velocity at low altitudes (30-60 mi). It basically travels across 90 degrees of azimuth in less than a minute.

Discovery will seem to "flicker," then abruptly wink-out 8 minutes and 23 seconds after launch as the main engines shut-down and the huge, orange, external tank (ET) is jettisoned over the Atlantic at a point about 870 statute miles uprange (to the northeast) of Cape Canaveral and some 430 statute miles southeast of New York City.  At that moment, Discovery will have risen to an altitude of 341,600 feet (64.7 statute miles), while moving at 17,579 mph and should be visible for a radius of about 770 statute miles from the point of Main Engine Cut Off (MECO). 

Following MECO and ET separation, faint bursts of light caused by reaction control system (RCS) burns might be glimpsed along the now-invisible shuttle trajectory; they are fired to build up the separation distance of the orbiter from the ET and to correct Discovery's flight attitude and direction.

Lastly: before hoping to see the shuttle streak across your local sky, make sure it has left the launch pad! 

What happens in case of a scrub?

Because Russia plans to launch a Soyuz spacecraft carrying the next space station commander and flight engineer on Mar. 26, the docked phase of the shuttle mission must be done by then to avoid a conflict. To get in a full-duration four-spacewalk mission, Discovery must take off by Mar. 13.  Should the launch be postponed to Mar. 12, liftoff would come at 8:54 p.m. EDT; on Mar. 13, it would come at 8:32 p.m. 

By giving up one or two of the mission's planned spacewalks, along with off-duty time, Discovery could launch as late as Mar 16 or 17 in a worst-case scenario. But that would coincide with bright twilight or sunset for parts of the Eastern Seaboard.

After that, the flight would slip to April 7, which would make it a daytime launch.

• Video: Night Shuttle Launch
• Gallery: 20 Great Rocket Launches
• Space Shuttle: Complete Launch Coverage

Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for The New York Times and other publications, and he is also an on-camera meteorologist for News 12 Westchester, New York.

A recently discovered comet is making its closest approach to Earth in the next few days and offers anyone with binoculars or a small telescope a chance to see some frozen leftovers of our solar system's making.

Comet Lulin has, as expected, crossed the threshold to naked-eye visibility for people with dark, rural skies. It hovers just inside that envelope of visibility, however, and is not likely visible from cities, where the glare of urban lights can drown out all but the brightest night-sky objects.

"The comet is now naked-eye (if you're out in the country) and is brightening every day as it approaches Earth," said Jack Newton, who has made several photographs of Lulin from his Arizona Sky Village, a residential community committed to pristine natural surroundings and dark skies. "Some feel it will reach maximum brightness on Saturday morning."

NASA has imaged the comet, too, finding that it is shedding into space enough water to fill an Olympic-size swimming pool every 15 minutes, as the sun boils the comet's surface material away.

Lulin will be closest to Earth -- about 38 million miles, or 160 times farther than the moon -- on Feb. 24 [sky map].

Challenging to find

The comet, tinted green because of the chemicals in its head, or coma, has been a delight to seasoned skywatchers like Newton, who know how to find faint objects in the sky and then zoom in on them with binoculars and telescopes.

But a comet this dim can prove challenging for the rest of us.

"For those not-so-seasoned folks, I would advise them not to expect anything awe-inspiring," said Joe Rao, SPACE.com's Night Sky Columnist. "Visually to the naked eye in a dark sky, Lulin looks like a dim, fuzzy 'star' and in a small telescope it appears like a fuzzball ... somewhat brighter and more concentrated near the center and more diffuse around the edges.  As comets go, it's nice, but casual skywatchers are more likely to say, 'That's it?' as opposed to more experienced observers who might actually utter, 'Oh, wow!'"

Comets are known for their tails, which, like the fuzzy heads, form when solar radiation breaks up surface ice and minerals. The stuff escapes into space, forming an ephemeral atmosphere that glows with reflected sunlight. Lulin has formed and lost its tail at least twice, when gusts of solar wind tore it off.

Observers last night found little or no tail.

Worth a look

Still, even a cosmic fuzzball can inspire a wee bit of awe as one goes out, looks up, and spots a frozen ball of rock and ice that's been hurtling through the solar system since its formation 4.6 billion years ago, just now making its first pass through the inner solar system.

For most locations in the Northern Hemisphere, Lulin rises soon enough to be spotted in the late evening if you know where to look. The light from objects nearer to the horizon must pass through more of Earth's atmosphere, however, so the best time to see the comet is after midnight, when it's high in the sky.

SPACE.com asked Jack Newton if he'd recommend the comet to casual observers Saturday night. "Absolutely," he said. "Binoculars should be just great."

On the night of Feb. 23, Lulin will be just 2-degrees south-southwest of the planet Saturn, which Rao said will serve as a good benchmark to locate the comet.

800 gallons of water a second

Meanwhile, NASA used its Swift Gamma-ray Explorer satellite to photograph Lulin in ultraviolet and X-rays.

"The comet is quite active," said Dennis Bodewits of NASA's Goddard Space Flight Center in Maryland. "The UVOT data show that Lulin was shedding nearly 800 gallons of water each second."

"We are looking forward to future observations of Comet Lulin, when we hope to get better X-ray data to help us determine its makeup," said Jenny Carter, at the University of Leicester, U.K., who is leading the study effort. "They will allow us to build up a more complete 3-D picture of the comet during its flight through the solar system."

The comet is headed away from the sun now, back to the dark depths of the outer solar system. It will fade from our view by mid-March.

The most brilliant of all the constellations dominates our evening sky this week, climbing well up in the south around 9 p.m. local time.  It is, of course, Orion, the Hunter.  But just exactly who was he?  

As is also the case with the mighty Hercules, the figure of Orion has been associated in virtually all-ancient cultures with great national heroes, warriors, or demigods.  Yet, in contrast to Hercules, who was credited with a detailed series of exploits, Orion seems to us a vague and shadowy figure. 

The ancient mythological stories of Orion are so many and so confused that it is almost impossible to choose among all of them.  Even the origin of the name Orion is obscure, though some scholars have suggested a connection with the Greek "Arion," meaning simply warrior.  All, however, agree that he was the mightiest hunter in the world and he is always pictured in the stars with his club upraised in his right hand. 

Hanging from his upraised left hand is the skin of a great lion he has killed and which he is brandishing in the face of Taurus, the Bull, who is charging down upon him.

Where stars are born

Below Orion's famous three-star belt is undoubtedly one of the most wonderfully beautiful objects in the sky: the Great Orion Nebula.  It appears to surround the middle star of a fainter trio of stars in a line that marks the hunter's sword. 

The nebula is invisible to the unaided eye, though the star itself appears a bit fuzzy.  It is resolved in good binoculars and small telescopes as a bright gray-green mist enveloping the star.  In larger telescopes it appears as a great glowing irregular cloud. 

A sort of auroral glow is induced in this nebula by fluorescence from the strong ultraviolet radiation of four hot stars entangled within it. Edward Emerson Barnard (1857-1923), for many years an astronomer at Yerkes Observatory, once remarked that it reminded him of a great ghostly bat and that he always experienced a feeling of surprise when he saw it. 

The Great Orion Nebula is a vast cloud of extremely tenuous glowing gas and dust, approximately 1,600 light-years away and about 30 light years across (or more than 20,000 times the diameter of the entire solar system).  Astrophysicists now believe that this nebulous stuff is a stellar incubator; the primeval chaos from which star formation is presently underway.    

In living color

One of the pleasures of stargazing is noticing and enjoying the various colors that stars display in dark skies.  These hues offer direct visual evidence of how stellar temperatures vary. 

In Orion, ruddy Betegeuse and bluish Rigel provide an excellent color contrast but we can easily find other colors as well.  Look at orangish Aldebaran and yellowish Pollux.  And considerably removed from the winter groupings, is brilliant topaz Arcturus, usually regarded as a spring star, but now, in the dead of midwinter, rises this week between 10:30 and 11 p.m. and quickly holds forth in solitary splendor in the east-northeast. 

Even as you observe these stellar colors, do you notice that they're recognizable only for the brightest stars?  This is due to the physiology of the eye, more specifically, the fact that the color sensors on the retina – the cones – are insensitive to faint light.  Under dim illumination the retinal rods take over.  But their greater light sensitivity is offset by their color blindness.  This is why we see all faint stars as white. 

However, if we look at them through binoculars or a telescope, their amplified brightness stimulates the cones, which detect their color. 

• Online Sky Maps and More
• Sky Calendar & Moon Phases
• Astrophotography 101

Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for The New York Times and other publications, and he is also an on-camera meteorologist for News 12 Westchester, New York.

Astronomer Robert H. Baker (1880-1962) once wrote of the Great Hunter or Celestial Warrior, Orion, that he shines "like a gigantic piece of celestial jewelry through the frosty winter air."

Indeed, Orion is by far the most brilliant of the constellations and is visible from every inhabited part of the Earth.  As darkness descends, he clearly dominates the southeast sky. Three bright stars in line in the middle of a bright rectangle decorate Orion's belt, which point northward to the clusters of the Hyades and Pleiades of Taurus, and southward to the Dog Star Sirius. 

Within Orion we find two immense stars, Rigel and Betelgeuse, apparently at two entirely different periods in a star's existence.           

A tale of two stars

Rigel (the "Left Leg of the Giant"), is a blue-white supergiant star, one of the rarest breeds in our galaxy; it's one of the most intrinsically luminous of all stars and one of the hottest, apparently just reaching the prime of its life in the time span of a star and literally "burning the candle at both ends."  It has been computed that Rigel's luminosity is something like 36,000 times that of the sun.  Our best estimates currently place it at 773 light-years away. 

In contrast, red supergiants like Betelgeuse ("The Armpit of the Giant") are gigantic bloated globes of cooler gas.  If such a star were to replace the sun in the solar system, it might extend beyond Mars' orbit. 

Betelegeuse is near the end of its career, some 522 light-years away, but not shining with a steady light.  It is a "pulsating" star, expanding and contracting spasmodically with a diameter that varies from 550 to 920 times that of the sun, but so irregular are these pulsations that no one can predict exactly when it will expand or contract. 

In trying to describe Betelegeuse many years ago, a lecturer at New York's Hayden Planetarium noted that it is "like an old man with his strength almost entirely spent, panting in the asthmatic decrepitude of old age."

Stellar genealogy

Stars produce their energy by fusing hydrogen into helium deep within their cores.  When a star accumulates sufficient helium in its core, its energy output increases significantly, and it swells into a red giant or supergiant, like Betelgeuse. 

This is what Rigel will become in a few million years.  In such stars, the core produces successively heavier elements to balance the incessant crush of gravity.  But once the core begins creating iron, a star's days are numbered; the formation of elements heavier than iron consumes rather than produces energy.  Eventually, since the core can no longer support the star's vast weight it collapses, triggering a cataclysmic supernova explosion. 

Betelgeuse is in its final stage and could explode in only a few million years.

Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for The New York Times and other publications, and he is also an on-camera meteorologist for News 12 Westchester, New York.

During the next few weeks on some clear moonless early morning, if you are fortunate to be far from any haze and bright lights, keep a close watch on the eastern horizon about two hours before sunrise. If you're lucky you might catch a glimpse of a ghostly column of light extending upward into the sky. 

Many have been fooled into thinking that it's beginning of morning twilight and indeed the Persian astronomer, mathematician and poet Omar Khayyam (1050? -1123?) referred to this ghostly glow as the "false dawn" in his poem, The Rubaiyat. 

That faint ghostly glow was once thought to be solely an atmospheric phenomenon: perhaps reflected sunlight shining on the highest layers of Earth's atmosphere.  We know now that while it is indeed reflected sunlight, it is being reflected not off our atmosphere, but rather off of a non-uniform distribution of interplanetary material; debris left over from the formation of our solar system. 

These countless millions, if not billions of particles – ranging in size from meter-sized mini-asteroids to micron-sized dust grains -- seem densest around the immediate vicinity of the sun, but extend outward, beyond the orbit of Mars and are spread out along the plane of the ecliptic (the path the sun follows throughout the year).  Hence the reason for the name Zodiacal Light is because it is seen projected against the zodiacal constellations. 

Before the break of dawn

The best time to see the Zodiacal Light is when the ecliptic appears most nearly vertical to the horizon.  For those in the Northern Hemisphere, the best morning views in the eastern sky will come during the next few weeks without the interference of bright moonlight. Conversely, for those who live in the Southern Hemisphere, the best views now are in the western evening sky right after sunset. 

Those who live in the tropics or at the equator are luckiest of all since the Zodiacal Light is always very conspicuous from these regions.  This is probably because from these locations the ecliptic is always favorably oriented allowing views of the Zodiacal Light both in the western evening sky and eastern morning sky all year long. 

For northerners at this particular time of the year, it is just before morning twilight begins (about 90 minutes before sunrise), that the Zodiacal Light should appear at its brightest and most conspicuous. 

A ghostly slanted pyramid

The Zodiacal Light is something you have to see to believe. 

My best views of it came from southeast Arizona back in 2001.  I had chosen that part of the country for a view of a pristinely dark and starry sky to serve as the backdrop for an upcoming display of Leonid meteors.  Imagine my surprise when I stepped outside on my first early morning watch, and was surprised to see what looked like the glow of a town or small city just beyond the horizon to my east.  It took a while for me to realize that what I was seeing was not urban light pollution, but the Zodiacal Light!

To a discerning eye, its diffuse shape somewhat resembles a tilted cone, wedge or slanted pyramid.  At the base of the cone, the light may extend some 20 to 30-degrees along the horizon.  At its best, it can approach or even equal the Milky Way in brightness, but more often than not it is so faint that even a small amount of atmospheric haze can obscure it.  On exceptionally clear nights, the tapering cone might be seen to stretch more than halfway to the zenith. 

In fact, should you be blessed with such conditions – absolutely no artificial lighting, smoke or haze – you should also try to see the Zodiacal Band, which runs along the entire ecliptic and usually averages about 5 to 10-degrees in apparent width.    

Counterglow

There is yet another ghostly glow in the sky which few have seen or heard about. 

This is the Gegenschein, derived from a German word meaning "counterglow," since it is always opposite or "counter" in position to the sun in the sky.  The Gegenschein is visible only with the unaided eye, as it is far too large and diffuse to be viewed with a telescope or even binoculars. 

The exact nature of the Gegenschein is still somewhat of a mystery, though most think that – like the Zodiacal Light – it might be some sort of tail formed by minute particles from our atmosphere that are streaming out into space away from the Earth in the opposite direction from the sun.   

Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for The New York Times and other publications, and he is also an on-camera meteorologist for News 12 Westchester, New York.

Scientists have created a 3-Dpicture of a luminous and mountainous site on the moon that holds promise as apossible future location for a lunar colony.

The spot, near the moon's southpole, is called the "peak of eternal light" because it isalmost continuously exposed to sunlight.

Researchers created the new 3-D image using data taken bythe Advanced Moon Micro-Imager Experiment (AMIE) camera carried by the EuropeanSpace Agency's SMART-1(Small Missions for Advanced Research in Technology) robotic moon mission.

"AMIE is not a stereo camera, so producing a 3-D modelof the surface has been a challenge," said ESA researcher Detlef Koschny.  "We?ve used a techniquewhere we use the brightness of reflected light to determine the slope and, bycomparing several images, put together a model that produces a shadow patternthat matches those observed by SMART-1."

Koschny plans to present the images Sept. 26 at the EuropeanPlanetary Science Congress in M?nster, Germany.

During its orbits around the moon, which lasted from November 2004 until September 2006, AMIEtook a total of 113 images of the peak, located close to the rim of theShackleton Crater on the lunar south pole. In all but four of the images, thepeak was illuminated by sunlight.  

The peak of eternal light could bea promising spot for a future manned moon landing or even a lunarcolony, because the near-continuous sunlight that shines down couldgenerate a constant electricity supply. In addition, the shadowed cratersnearby are in perpetual darkness and may hold water ice deposited overmillennia by impacting comets and hydrogen and oxygen particles contained inthe solar wind.

To create the 3-D map of the area,the team, led by Bj?rn Grieger of ESA?s European Space Astronomy Centre inMadrid, analyzed five images taken from different angles. By comparing theimages, and mapping all of their pixels onto a grid, the researchers calculatedthe angles of the peak's slopes and produced a topographical model.

After its years in orbit, theSMART-1 satellite eventually crashedinto the moon as planned in September 2006.

• SMART-1: Mission Gallery
• NASA Weighs U.S. Strategy for Moon Exploration
• Top 10 Cool Moon Facts

Scientists have found more intriguing evidence for darkenergy ? one of nature's most befuddling phenomena.

Dark energy is thought to make up about 74 percent of theuniverse, while dark matter ? a mysterious form of matter that scientists canonly detect by noting its gravitational pull on things ? makes up about 22 percent.That leaves only 4 percent of the universe composed of things we can see andtouch: the normal protons, electrons and neutrons called baryonic matter.

Scientists don?t know what darkenergy is, but they observe its tugging effect, which causes the expansionof the universe to accelerate. Now they have seen this mysterious force in someof the largest known features of the cosmos, called superclusters andsupervoids.

The former are particularly crowded areas of space, each witha lot of galaxies huddled in a region half a billion light-years across, whilethe latter are the opposite, rather barren expanses notably lacking galaxies.

Astronomers led by Istv?n Szapudi of the University ofHawaii Institute for Astronomy observed dark energy stretching out these areasby detecting changes in rays of microwave light before and after they passedthrough the regions.

?"When a microwave enters a supercluster,it gains some gravitational energy, and therefore vibrates slightlyfaster," Szapudi said. "Later, as it leaves the supercluster, itshould lose exactly the same amount of energy. But if dark energy causes theuniverse to stretchout at a faster rate, the supercluster flattens out in the half-billionyears it takes the microwave to cross it. Thus, the wave gets to keep some ofthe energy it gained as it entered the supercluster."

Szapudi, with University of Hawaii postdoctoral researcherMark Neyrinck and graduate student Benjamin Granett, analyzed a map of thevarying strength of the microwave radiation left over from the Big Bang, calledthe cosmic microwave background radiation (CMB), across the universe. Theymatched this data to a map of the universe with the 50 largest supervoids andthe 50 largest superclusters plotted, based on information from the SloanDigital Sky Survey, a project that mapped the distribution of galaxies over aquarter of the sky.

As the researchers predicted, the microwaves were a bitstronger if they had passed through a supercluster, and a bit weaker if they hadpassed through a supervoid.

?With this method, for the first time we can actually seewhat supervoids and superclusters do to microwaves passing through them,?Granett said.

The team will detail their findings in the AstrophysicalJournal Letters in August or September.

• Top 10 Strangest Things in Space
• Nearby Evidence for Dark Energy
• Images: Hubble's New Views

Of the imaginary coordinate lines that astronomers and navigators use in mapping the sky, perhaps the most important one is the ecliptic, the apparent path the sun appears to take through the sky as a result of the Earth's revolution around it.

Because of the Earth's yearly revolution around the sun, the sun appears to move in its annual journey through the heavens with the ecliptic as its path. Technically then, the ecliptic represents the extension or projection of the plane of the Earth's orbit out towards the sky.

But since the moon and planets also move in orbits, whose planes do not differ greatly from that of the Earth's orbit, these bodies, when visible in our sky, always stay relatively close to the ecliptic line. In other words, our solar system can be best defined as being somewhat flat, with the planets moving in very nearly the same plane.

It is for this reason that most sky charts plot the position of the ecliptic; it is something of a warning to sky watchers that strange "stars" (planets) often appear near and along this path through our heavens, as well as the moon.Usually the moon and planets are not positioned exactly on the ecliptic (because they're not located exactly in the same orbital plane as Earth), but lie within several degrees of it and form a sort of narrow strip encompassing the entire sky which we call the Zodiac.

The ecliptic runs exactly along the middle of the Zodiac.

The "Classic Twelve"

Twelve constellations through which the ecliptic passes form the Zodiac. The name is derived from the Greek, meaning "animal circle," and also is related to the word "zoo," coming from the fact that most of these constellations are named for animals, such as Leo, the Lion; Taurus, the Bull; and Cancer, the Crab, just to name a few.

These names which can be readily identified on sky charts are familiar to millions of horoscope users (who — ironically — would be hard pressed to find them in the actual sky!).

If we could see the stars in the daytime, we would see the sun slowly wander from one constellation of the Zodiac to the next, making one complete circle around the sky in one year.

Ancient astrologers were able to figure out where the sun was on the Zodiac by noting which was the last zodiacal constellation to rise ahead of the sun, or the first to set after it. Obviously, the sun had to be somewhere in between. As such, each month a specific constellation was conferred the title of "House of the sun," and in this manner each month-long period of the year was given its "sign of the Zodiac."

Some discrepancies

Interestingly, however, the "sign" which has been assigned for a given month in the horoscope that you'll find in your daily newspaper is not where the sun actually is for that particular month, but where it would have been several millennia ago!

This is due to the "wobble" of the Earth's axis(known as precession); yet today's astrologers, who believe that the sun, moon and planets mysteriously direct our lives, continue to adhere to star positions that for all intents and purposes are out of date by thousands of years!

In addition, the ecliptic crosses through the constellation of Ophiuchus, the Serpent Holder. In fact, the sun spends more time traversing through Ophiuchus than nearby Scorpius! It officially resides in Scorpius for less than a week: from Nov. 23 through 29. It then moves into Ophiuchus onNovember 30 and remains within its boundaries for more than two weeks — untilDec. 17. And yet the Serpent Holder is not considered a member of the Zodiac and so must defer to Scorpius!

In addition, because the Moon and planets are often positioned either just to the north or south of the ecliptic, it allows them to sometimes appear within the boundaries of a number of other non-zodiacal star patterns.In fact, as pointed out by the well-known astronomical calculator,Jean Meeus, along with Ophiuchus, there are nine other constellations that occasionally can be visited by the Moon and planets: Auriga, the Charioteer;Cetus, the Whale; Corvus, the Crow; Crater, the Cup; Hydra, the Water Snake;Orion, the Hunter; Pegasus, the Flying Horse; Scutum, the Shield; and Sextans, the Sextant.

So in truth, there really aren't twelve zodiacal constellations, but twenty-two!

Origin of "Ecliptic"

Although the moon's orbit is inclined 5.5 degrees to the Earth's orbital plane, periodically there will come times when it crosses over the ecliptic.

Should this happen when the moon is at new phase, it will end up crossing in front of the sun causing a solar eclipse. If the moon crosses over the ecliptic when the moon is at full phase, it will pass into the shadow of the Earth resulting in a lunar eclipse. Usually when the new moon is in the vicinity of the sun it appears to pass above or below it and no eclipse occurs. Similarly, the full moon usually misses the Earth's shadow by sweeping above or below it.

Only when all three bodies (sun, Earth and moon) are on a straight line occupying the plane of the ecliptic can an eclipse occur.

Hence the name "ecliptic": the place where eclipses occur.

• Your Astrological Sign May Not Be What You Think It Is
• Why the Night Sky Changes with the Seasons
• Image Gallery: Constellations

Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for The New York Times and otherpublications, and he is also an on-camera meteorologist for News 12 Westchester, New York.

TUCSON,Ariz. ? NASA?s Phoenix Mars Lander sent back images of the blind spotunderneath it today as mission scientists gear up for the craft's robotic armto touch the planet's soil for the first time. The spacecraft also encounteredits first glitch, with a short circuit in one of its instruments, missionscientists said at a briefing on Friday.

Phoenix?srobotic arm was maneuvered so that the camera at the end of it could image the spaceunderneath the lander, which is a blind spot for the stereo camera on topof the lander?s deck. The images showed some interesting tabular formations, asrobotic arm co-investigator Ray Arvidson, of Washtington University in St.Louis, described them.

"Wedon?t know what they are. They could be exposures of ice, or they could beexposures of rocks," Arvidson said at a briefing here at the University ofArizona. ?We're really pushing for ice, but we don?t know if that's the caseyet.?

The$420 million dollar Phoenix mission is designed todig down to the layers of water ice thought to lie just under the surfaceof the north polar region of Mars, where it landed on Sunday. Instruments onthe spacecraft are designed to analyze soil samples to see if the ice was onceliquid and could have created a habitable zone for possible microbial life atsome point in Mars' past.

Missioncontrollers have encountered a problem with one of these instruments, theThermal and Evolved-Gas Analyzer (TEGA) that is designed to heat up soilsamples until vapors come off and then to analyze those vapors to detectthe composition of the soil.

Theglitch seems to be a short circuit in a filament in a part of the instrumentthat ionizes the vapors before they are sent to the detector, said TEGAco-investigator William Boynton of the University of Arizona. There are twofilaments in the detector however, and TEGA scientists are now investigatingwhether they can operate the instrument with just the one filament. They willalso being sending up diagnostic instructions over the next few days.

"We'requite optimistic that we have a workaround that will let us operate theinstrument," Boynton said.

Meanwhile,mission scientists are also looking for more information on the soil near thelander so that they can begin digging for samples. The first step will beimaging all three of the landers' footpads with the robotic arm camera to makesure the craft is stable on the ground, mission scientists said.

Afterthat, mission scientists plan to perform a "soil touch," whichinvolves moving the scoop at the end of the robotic arm and making a dent inthe soil, then turning the scoop around and imaging the dent to make sure thatcontrollers know how to reach the soil, Arvidson told SPACE.com.

Thenext step will be to do what mission scientists call a "dig and dump"where they will practice having the robotic arm scoop up the soil and dump itdown again.

Missioncontrollers are waiting to get data back from Phoenix?s Friday night downlinkon one of the proposed ?dig and dump? sites to decide when and where to performthe soil touch maneuver.

Clickhere for SPACE.com'sPhoenix mission coverage and a linkto NASA TV.

• Video: The Nail-Biting Landing of Phoenix on Mars
• Video: Looking for Life in All the Right Places
• Images: Phoenix on Mars!

TUCSON, Ariz. - NASA?sPhoenix Mars Lander has flexed its robotic arm for the first time and takena fish-eye panorama of its surroundings, mission scientists said Thursday.

?We have now achieveda major milestone for this mission,? said Phoenix project manager BarryGoldstein of NASA?s Jet Propulsion Laboratory (JPL) via a video link in a mission briefing held hereat the University of Arizona.

Phoenix beamed backimages that confirmed it had successfully unstowed its scoop-tipped arm, as it steadilysettles in at its northern polar home since its successfulSunday landing.

?I?m ecstatic to let youknow that [the robotic arm deployment] was successful,? said Matt Robinson, theRobotic Arm Flight Software Lead at JPL. ?It is raring to go. It?s busted loosenow and we?re ready to go.?

Phoenix also sent backa completed black-and-white panorama mosaic of its landing site, showing thedeployed solar arrays, robotic arm, meteorological mast and the flat terrainstretching out toward the horizon. The $422 million spacecraft is designedto dig down into the Martian arctic soils to the layers of water icethought to lie beneath the surface.

?We have a veryhummocky terrain,? said Phoenix principal investigator Peter Smith of theUniversity of Arizona, describing the polygonal-shaped bumps that cover thearctic landscape and which are separated by trenches in the soil. The shapesare believed to be formed by the expansion and contraction of the water iceunderneath.

The images also show ascattering of ?flat, table-like rocks,? as Smith described them.

The Phoenix scienceteam has begun naming the rocks they find to keep track of them, using a fairytale and folklore theme (so that the science team can have a little fun, Smithsaid). The rocks that have been named so far include ?Humpty Dumpty,? the?King?s Men,? and ?Alice? (in reference to Lewis Carroll?s ?Alice inWonderland?).

The science team plansto use the robotic arm to move some of the rocks, which are only a few inchesacross, to see what?s underneath them. They will also investigate the origin ofthe rocks.

?The rocks don?t comewith labels, it?s a little hard to tell where they came from,? Smith said.

But first, missioncontrollers plan to test out the robotic arm?s joints in higher and lowertemperatures on the red planet, ?and that?s because the robotic arm is going tobe required to move at a range of temperatures,? Robinson explained. Weatherreports from the surface so far show a high temperature at the landing siteof -22 degrees Fahrenheit (-30 degrees Celsius) to a low of -112 F (-80 C).

Controllers will alsoposition the arm so that the camera attached to its scoop can snap a picture ofthe surface under the lander, to make sure no rocks are there.

Scientists havedivided the terrain into two parts: a ?national park? area that missionscientists will leave untouched until they have better characterized theenvironment, and an area they can use to test out the robotic arms diggingcapabilities.

?It?s more of aSuperfund site over there, so we?re allowed to mess that part up a bit,? Smithsaid.

Digging likely won?tstart until the middle of next week, mission scientists said.

NASA's next Phoenix mission briefing will be broadcast liveon NASA TV at 2:00 p.m. EDT (1600 GMT) on Friday, May 30. Clickhere for SPACE.com's Phoenix mission coverage anda linkto NASA TV.

• Video: Sounds From Phoenix Mars Lander's Descent
• New Images: Phoenix on Mars!
• Video: The Nail-Biting Landing of Phoenix on Mars

When spacetravelers finally traipse across the dusty Martian surface, they'll knowjust what kind of terrain to expect thanks to scientists at the European SpaceAgency who are producing the first "hiker's maps" of the red planet.

The newtopographic maps, based on data collected by the ESA's MarsExpress spacecraft, could become the standard cartographic reference forfuture Martian research, as well as explorationon foot.

The ESAeventually will create topographic maps for the entire surface of Mars, which would mean more than 10,000maps each of equal area.

Forstarters, researchers have created a map of the Iani Chaos region, chosen forthe rock "islands" that litter the landscape in an interesting,chaotic pattern. These rocks are likely the remains of a previous Martiansurface that collapsed when the icesupporting subsurface cavities melted from volcanicheat.

All the mapswill feature the names of geologicalfeatures and detailed height contours of the landscape.

Contourlines are superimposed onto high-resolution images of Mars taken by theHigh-Resolution Stereo Camera (HRSC) onboard Mars Express. The lines help theeye to follow the morphology of the surface.

The data havealso been transformed into 3-Dcomputer models of Mars's surface.

• Mars Madness: A Multimedia Adventure!
• Image: Where Floods Once Flowed
• Images: Mars Express Discoveries
• All About Mars

Instrumentsaboard the VenusExpress spacecraft have obtained the first large-area temperature map ofthe southern hemisphere of Venus'searing surface.

Byidentifying hot spots on this inhospitable planet, the new data--obtained by theVisible and Infrared Thermal Imaging Spectrometer (VIRTIS)--could spot active volcanism.

VIRTIS lookedthrough the thick carbon dioxide curtain surrounding Venus and detected theheat directly emitted by the hot rocks on the ground. The instrument made useof the so-called infrared spectral "windows" present in the Venusianatmosphere. Through these windows thermal radiation at specific wavelengths canleak from the deepest atmospheric layers, pass through the dense cloud curtain,and then escape to space, where it can be detected.

On Venusthere are no day and night variations of the surface temperature. The heat isglobally trapped under a thick carbon-dioxide atmosphere, with pressure 90times higher than on Earth. Instead, the main temperature variation is due totopography.

Just likeon Earth, mountain tops are cooler, whereas the lowlands are warmer. The onlydifference is that on Venus cold means 837 degrees Fahrenheit (447 degreesCelsius), while warm means 891 degrees Fahrenheit (477 degrees Celsius). Suchhigh temperatures are caused by the strongest greenhouseeffect found in the Solar System.

The VIRTISresults represent a major step forward in our attempt to identify specific featureson the surface of Venus, said J?rn Helbert from the German Aerospace Center's (DLR) Institute of Planetary Research in Berlin, Germany. "By peelingoff the atmospheric layers from the VIRTIS data, we can finally measure thesurface temperature."

Theresearchers hope to identify volcanoes on the surface of Venus. In the SolarSystem, besides Earth, activevolcanoes have been observed only on Io, a satellite of Jupiter, on Neptune's satellite Triton,and on Saturn's moon Enceladus.Venus is the most likely planet to host other active volcanoes.

Thefindings were presented today at the annual fall meeting of the AmericanGeophysical Union in San Francisco.

• Venus and Earth: Worlds Apart
• Hot Discovery: Dark Vortex on Venus
• European Probe Reaches Final Orbit Around Venus
• Images: Below the Clouds of Venus

The public space travel business is picking up suborbital speed thanks to a variety of private rocket groups and their dream machines.

Joining the mix is Blue Origin's New Shepard Reusable Launch System. It is financially fueled by an outflow of dollars from the deep pockets of billionaire Jeff Bezos, founder of Amazon.com.

The Bezos-backed Blue Origin, LLC commercial space outfit has recently turned in a draft environmental assessment (EA) for their West Texas launch site to the Federal Aviation Administration's (FAA) Associate Administrator for Commercial Space Transportation (AST) in Washington, D.C.

The document is the best glimpse yet of what Blue Origin is scoping out to develop "safe, inexpensive and reliable human access to space."

Privately-owned property

The more than 200-page draft EA is a necessary step required by the FAA/AST for Blue Origin to get the needed permits and/or licenses to fly their rocket hardware.

Blue Origin proposes to launch its reusable launch vehicles (RLVs) on suborbital, ballistic trajectories to altitudes in excess of 325,000 feet (99,060 meters) from a privately-owned space launch site in Culberson County, Texas.

As outlined in the EA, the Blue Origin launch site would be approximately 25 miles (40.2 kilometers) north of Van Horn, Texas. It lies within a larger, privately-owned property known as the Corn Ranch. Access to the proposed launch site is from Texas Highway 54, which is approximately five miles (8 kilometers) west of the proposed project's center of operations.

Also on the group's to do list at the site is putting in place a vehicle processing facility, a launch complex and vehicle landing and recovery area, as well as an astronaut training facility, and other minor support amenities [Map].

Incremental testing

The strategy is to build the New Shepard suborbital vehicle incrementally, starting with low-altitude tests, progressing to higher-altitude testing, and culminating with commercial flights. Early testing would use prototype vehicles that are smaller and/or less capable than the proposed final design.

Prototype craft would use the same or a subset of the same types of propellants as the operational New Shepard RLV in smaller quantities and would use the same ground facilities, infrastructure, and equipment.

Each new trial product would fly to higher altitudes and/or demonstrate additional subsystems than the previous prototype. Eventually, Blue Origin proposes to perform multiple flight tests of the actual operational New Shepard RLV system carrying Blue Origin personnel before commencing commercial operation.

As detailed in the EA, the New Shepard RLV system would be comprised of a propulsion module and a crew capsule capable of carrying three or more space flight participants on roundtrip treks from the ground to the edge of space. The crew capsule is perched on top of the propulsion module. The stacked vehicle would have a roughly nose cone shape with a base diameter of approximately 22 feet (7 meters) and a height of approximately 50 feet (15 meters).

The propulsion module would be fully reusable, would carry its own avionics, and would operate autonomously under the control of on-board computers. The propulsion module would use 90 percent concentration hydrogen peroxide, called high test peroxide (HTP) and rocket propellant (RP) grade kerosene as the propellants.

During an abort situation, the crew capsule would separate, using small solid-rocket motors to safely recover the space flight participants. The abort module containing the solid-rocket motors would then jettison from the crew capsule. After the crew capsule departs, the propulsion module would attempt to steer back to the landing pad using aerodynamic surfaces and utilize its engines to make a controlled, powered vertical landing.

Because Blue Origin's launch vehicle would ascend and descend vertically, sonic booms would propagate away from the Earth's surface during launch and towards terra firma during descent.

Powered landing

The New Shepard test pad would be up to 32,292 square feet (3,000 square meters) in area. A separate flat landing pad of equal size would be located 3.8 miles (6.1 kilometers) north of the Blue Origin vehicle processing facility.

The New Shepard RLV launch, flight, and landing activities would require less than a 10 minute period to complete. Powered to roughly 125,000 feet (38,100 meters) under thrust from its main engines, the spaceship would chalk up some 110 seconds of flight. From there, the RLV would coast up to a height greater than 325,000 feet (99,060 meters). At top altitude, the vehicle would then return to the landing pad under gravity free-fall conditions until the main engines are restarted to enable a powered landing.

Blue Origin has not completed development of the New Shepard vehicle or its engines, according to the EA, so no test results are available. Nevertheless, as stated in the document, a thrust of 230,000 pounds force is expected at vehicle liftoff.

Blue Origin would ship the New Shepard propulsion module and crew capsule RLVs to the West Texas Launch Site separately. The RLVs would originate at Blue Origin's manufacturing and assembly facilities in the state of Washington and would travel via ground to West Texas. Blue Origin plans no more than ten total RLV shipments during the five-year period from 2006-2010.

Flight rate

Blue Origin has outlined within the pages of the EA the following activities envisioned at the West Texas launch site over the next five years. These are:

• 2006: The majority of facility construction at the site would occur during this period. In the third and fourth quarters of 2006, Blue Origin would ship the first prototype low-altitude test vehicle to the site and conduct the first flight tests. Ten or fewer flight tests could be conducted in 2006, each to an altitude of approximately 2,000 feet (610 meters) for less than one minute.

• 2007-2009: Continued flight testing of prototype vehicles with incrementally increasing capability. During these years, Blue Origin proposes to gradually expand the operational envelope of its vehicles, conducting 25 or fewer launches per year. A wide range of tests are anticipated, ranging in altitude from under 2,000 feet (610 meters) to greater than 325,000 feet (99,060 meters), lasting one minute or less to over 10 minutes. Development tests of the crew capsule abort system would be conducted during this time frame. During this time period, some construction to upgrade the facility would also occur, adding additional infrastructure to support the increasing capabilities of the system.

• 2010 and beyond: Commercial operations may commence with the operational New Shepard vehicle in this timeframe. The flight rate would depend on market demand, but Blue Origin anticipates rates up to approximately 52 launches per year of the New Shepard RLV.

According to the EA, an experimental permit from the FAA would allow Blue Origin to carry out testing of reusable suborbital vehicles that would be launched or reentered solely for: Research and development to test new design concepts, new equipment, or new operating techniques; showing compliance with requirements as part of the process for obtaining a license; and crew training prior to obtaining a license for a launch or reentry using the design of the rocket for which the permit would be issued.

Public comment

Last year, on June 14 and 15, Blue Origin conducted a series of information meetings in Van Horn, Texas and Dell City, Texas. The firm's plan to construct and operate a commercial launch facility in Culberson County, Texas was detailed at those gatherings.

Now the Draft Environmental Assessment for the Blue Origin West Texas Commercial Launch Site has been released for public review and comment, explained James Stasny, spokesman for the FAA's Office of Commercial Space Transportation.

A paper copy of the draft is available at the Van Horn public library in Van Horn, Texas. A public hearing on the Blue Origin EA will be held on July 25th at the Van Horn Convention Center, with the public comment period about the rocket group's plans closing two days later, Stasny told SPACE.com.

When queried by SPACE.com about their environmental assessment, Blue Origin declined to comment beyond what is detailed within their EA document.

Thrust vectoring and responsive throttling

Blue Origin's spaceship is patterned after Department of Defense/NASA work on the single-stage vertical-takeoff, vertical-landing Delta Clipper Experimental (DC-X) and Delta Clipper Experimental Advanced (DC-XA). It was repeatedly flown in 1993-1996 at the U.S. Army's White Sands Missile Range in New Mexico.

Among a list of distinctions, a 26-hour turnaround was achieved between the DC-XA's second and third flights - a first for any rocket. The flight program ended in July 1996 with the DC-XA suffering severe damage due to a landing strut - one of four-that failed to extend. The unbalanced vehicle tipped over on its landing pad and caught fire. Due to lack of follow-up money, the program was ended.

John Garvey was the flight engineer during the DC-XA phase of testing and now runs Garvey Spacecraft Corporation in Long Beach, California. He told SPACE.com that he's keeping an eye on how Blue Origin operates New Shepard in light of what was learned during DC-X/XA testing.

Garvey advised that if the descent and landing techniques for New Shepard are similar to those employed on the DC-X/XA, then both thrust vectoring and responsive throttling of the vehicle's engines will be required. That likely means, he added, Blue Origin engineers will spend loads of time on the test stand to flight qualify the spaceship's rocket motors, especially for human-carrying operations.

Unique hazards

"Their reported choice of hydrogen peroxide and RP-1 as propellants is interesting, particularly the hydrogen peroxide," Garvey noted. By comparison, the DC-X/XA used liquid oxygen and liquid hydrogen. 

"Numerous new entrants to the rocket business have favored-at least initially - hydrogen peroxide as an oxidizer instead of liquid oxygen, usually for perceived safety reasons, even though that means sacrificing performance," Garvey observed. 

However, highly concentrated hydrogen peroxide presents some unique hazards relative to liquid oxygen in flight operations as well as shipping and storage, Garvey said. Hydrogen peroxide can "rapidly decompose" if contamination is present.

"Every so often there is a story about an amateur rocketeer burning down the garage-or worse-due to such an accident," Garvey explained. "For whatever reason ... no major operational launch system has employed it for primary propulsion."

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• Floating Robotic Spheres: From the Millennium Falcon to the ISS
• The Grand SLAM: Rocketing Water to the Moon
• Daily Space Trivia

For centuries, humans have looked to the heavens for their gods and goddesses and clues for finding the nature of the universe.

Now, the largest ever-produced map of the universe gives those lost in the dark some direction, but is also confirms that the universe is full of dark energy, a strange force pushing galaxies apart at ever faster speeds.

This utterly inexplicable force is one of nature's great unsolved mysteries. Map or no map, scientists admit they're pretty clueless about what's going on.

"We now have a precise view of what makes up our universe, but little idea as to why," said Ofer Lahav, the head of the Astrophysics Group at University College London. "It is intriguing that the ordinary matter our bodies are made of and that we experience in everyday life only accounts for a few percent of the total cosmic budget."

Scientists have known since the 1920s that the universe is expanding. But it was only in the late 1990's that they realized it is doing so at an ever-increasing pace. Not sure how to explain this phenomenon, they concluded that some mysterious force, dark energy, is what's causing this acceleration.

This mysterious force is said to make up about 75 percent of the mass-energy budget of the cosmos.

The new cosmic map is a three-dimensional atlas of more than one million galaxies reaching a distance greater than 5 billion light-years. The most distant galaxies in the universe are more than 13 billion light-years away, and not all of them have been catalogued or even discovered.

The map was created using a new artificial intelligence technique that helps overcome challenges to figuring out how far galaxies are in a photograph that renders them all essentially in two dimensions.

"By using very accurate distances of just 10,000 galaxies to train the computer algorithm, we have been able to estimate reasonably good distances for over a million galaxies," said Adrian Collister of the University of Cambridge. "This novel technique is the way of the future."

To make such a map, astronomers have to find the distance between galaxies. Conventionally, this is done by taking a full spectrum of every galaxy and measuring how the light emitted by each one stretches as the universe expands. But this method is tedious and time consuming because it involves observing each galaxy and splitting the observed light into individual components to measure the light stretch.

However, with the new technique, researchers measured the amount of color distortion of a small sample of galaxies whose colors are well known and therefore avoided the need to obtain a full spectrum of every galaxy.

They then approximated the distance of a galaxy by looking at digital images of the sky and created a map of more than a million galaxies.

Soon, with a few simple clicks, any web surfer will be able to look at the new view of heavens. The map is to be made available free on the Internet.

• Dark Energy and Einstein Converge
• Nearby Evidence for Dark Energy
• Dark Matter and Dark Energy: One and the Same?
• Image Gallery: Hubble's Latest Views of the Universe

A new high-resolution map of Mars's magnetic field indicates that the red planet's crust once moved like present-day Earth's.

The map was pieced together from observations of Mars's magnetic field taken by NASA's Mars Global Surveyor (MGS). It reveals that the planet's surface was shaped in the same manner as Earth's - by giant crustal plates pulling apart or smashing together.

In 1999, MGS provided a glimpse of this type of activity over one region in the Southern Hemisphere. The new map is based on four years of data and covers the entire planet, yielding evidence that some of the main features on Mars, such as the Tharsis volcanoes and the Valles Marineris, were created in part by the same processes that created the Hawaiian Islands and Grand Canyon on Earth. 

Shifty surface

Crustal plates sit on top a layer of molten rock called the mantle, and when they slide around, they produce a pattern scientists refer to as "striping." As molten rock rises from the mantle, it breaks through the crust, pushing the plates apart. Once the molten rock reaches the surface, it cools and is magnetized in the direction of the planet's magnetic field.

Later on, this new surface will likewise be split apart by more rising material. On Earth, the magnetic field flips direction a few times every million years, so a flow that rises and cools in one period may have a different magnetic orientation to the one next to it. These alternating stripes are proof of both a strong magnetic field and tectonic activity.

Activity like this is widespread on Earth - particularly along the Mid-Atlantic Ridge - but had never been confirmed on Mars until this latest study.

"This map lends support to and expands on the 1999 results," said Norman Ness of the Bartol Research Institute at the University of Delaware. "Where the earlier data showed a 'striping' of the magnetic field in one region, the new map finds striping elsewhere. More importantly, the new map shows evidence of features, transform vaults, that are a 'tell-tale' of plate tectonics on Earth."

Mars mysteries

Confirming that Mars experienced plate tectonics at some point in its history helps explain some of the mysteries of Mars geology. The Tharsis volcanoes - which include the largest volcano in the solar system, Olympus Mons - lie in a straight line, but until now, scientists couldn't say why. With the new map, it is likely that they were formed from the motion of a crustal plate sitting over a "hotspot" in the mantle, just as the Hawaiian Islands are thought to have formed.

The Valles Marineris is a large canyon six times as long and eight times as deep as the Grand Canyon. It is 2,800 miles long, 125 miles wide, and nearly seven miles deep. Its features resemble what a tectonic plate being pulled apart would look like on Earth, and its stripe pattern is oriented in a way that scientists would expect from the plate motions implied by the new map.

"It's certainly not an exhaustive geologic analysis," said Mario Acuña, principal investigator for the Mars Global Surveyor magnetic field investigation at Goddard Space Flight Center. "But plate tectonics does give us a consistent explanation of some of the most prominent features on Mars."

This research was detailed in the Oct. 10 issue of the journal The Proceedings of the National Academy of Science.

• The Magnetic Personality of Ancient Mars
• Possible Ancient Equator of Mars Revealed
• Animation Shows How Mars Evolved, Where Water Hides
• Image Gallery: Amazing Mars

Mars is coming back.  The Red Planet, the only one whose surface we can see in any detail from the Earth, has begun the best apparition it will give us until the summer of 2018. 

Planet watchers have already begun readying their telescopes.

If this sounds familiar, you might recall a similar setup two years ago. This current apparition of Mars will not be as spectacular as the one in August 2003 when the planet came closer to Earth than it had in nearly 60,000-years.

Mars is currently in the constellation of Aries, the Ram and doesn't rise until around 10:45 p.m. local daylight time.  There is certainly no mistaking it once it comes up over the east-southeast horizon.  Presently shining at magnitude –0.8, it now ranks fifth among the brightest objects in the night sky, surpassed only by the Moon, Venus, Jupiter and Sirius (the brightest star in the sky). 

And as it continues to approach Earth, Mars will only be getting brighter in the coming weeks: it will surpass Sirius on Sept. 21 and on Oct. 4 it will rival Jupiter and as a consequence (until Nov. 26), hold forth as the second-brightest planet. 

Late on the night of Aug. 24, Mars will hover below and to the right of the waning gibbous Moon.  As you will see for yourself, the so-called Red Planet actually will appear closer to a yellow-orange tint – the same color of a dry desert under a high sun.

This time around, Mars comes closest to the Earth on the night of Oct. 29 (around 11:25 p.m. Eastern daylight time).  The planet will then lie 43,137,071 miles (69,422,386 kilometers) from Earth measured center to center. Mars will arrive at opposition to the Sun (rising at sunset, setting at sunrise) nine days later, on Nov. 7.

How big?

On Oct. 29, Mars' apparent disk diameter will be equal to 20.2 arc seconds.

To get an idea of how large this will appear in your telescope, Jupiter currently appears about 32 arc seconds across.  So, if you train your telescope on Jupiter during this week, keep in mind that Mars' disk will appear more than one-third smaller than that when it comes closest to Earth near the end of October. 

Another way to gauge how large this is would be to take a look at the Moon with a telescope and look at the brilliant rayed crater Tycho, probably the most prominent on the Moon's surface.  At its best, Mars should appear less than half the apparent size of Tycho (just the crater itself . . . not its rays).

While all this may sound small, keep in mind that this is still an atypically large size for Mars. In fact, from Oct. 23 through Nov. 5, Mars' apparent size will be equal to, or slightly exceed 20 arc seconds; larger than it will appear at any time until late June of 2018.  

How high?

From Oct. 29 through Nov. 9, Mars will blaze at magnitude –2.3, more than twice as bright as Sirius, but still inferior to Venus.  Mars will still be positioned within the constellation of Aries, the Ram, at a declination of +16 degrees. 

This is in contrast the August 2003 opposition, when it was situated much farther south at a declination of -16 degrees.  Back then, for observers especially in the northern United States and southern Canada, Mars was so low in the sky that atmospheric turbulence hampered telescopic work more than usual. 

But by the end of October 2005, northern observers will see Mars at a much higher altitude. When it reaches its highest point in the sky at around midnight local time, its altitude will be 59? at Seattle, Washington and 72? at Los Angeles, California.

Meanwhile, amateur and professional astronomers in Central America, north-central Africa and southernmost India will have exceptional visibility, for the planet will pass directly, or very nearly overhead!

Careful scrutiny

Around the time that Mars is closest, amateurs with telescopes as small as 4-inches and magnifying above 145-power should be able to make out some dusky markings on the small yellow-orange disk, as well as the bright white of the polar cap. 

But a final bit of caution: even a large telescope will show neophyte observers little when they first look at Mars. 

To say the least, Mars will likely prove to be a challenging object: the disk is relatively tiny and more often than not it will usually be blurred to a degree by the Earth's atmospheric seeing.  However, if you inspect the planet night after night, your eye will gradually become accustomed to the low contrasts and soft boundaries of the disk mottlings.

The most prominent area on Mars is a dark wedge known as Syrtis Major.  You soon might also grow familiar with the Martian rotation of 24 hours 37 minutes.  As a result, a particular feature comes to Mars' central meridian about 40 minutes later than it came the night before.  So, it would take a little over a month for a particular feature to come back to the middle of Mars' disk if you were viewing it at precisely the same time every night.

Basic Sky Guides

• Full Moon Fever
• Astrophotography 101
• Sky Calendar & Moon Phases
• 10 Steps to Rewarding Stargazing
• Understanding the Ecliptic and the Zodiac
• False Dawn: All about the Zodiacal Light
• Reading Weather in the Sun, Moon and Stars
• How and Why the Night Sky Changes with the Seasons
• Night Sky Main Page: More Skywatching News & Features

Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for The New York Times and other publications, and he is also an on-camera meteorologist for News 12 Westchester, New York.

NEW: See Video of Asteroid Toutatis' Flyby

The largest asteroid ever known to pass near Earth is making a close celestial brush with the planet this week in an event that professional and backyard astronomers are watching closely.

The space rock, named Toutatis, will not hit Earth, despite rumors of possible doom that have circulated the Internet for months. Humanity is very fortunate there won't be an impact, as the asteroid is large enough to cause global devastation.Toutatis is about 2.9 miles long and 1.5 miles wide (4.6 by 2.4 kilometers).

On Wednesday, Sept. 29 it will be within a million miles of Earth, or about four times the distance to the Moon.

No space rock this big will pass so close in the next century, scientists say. And while similarly large asteroids have hit the planet in the distant past, none so big have come so close since astronomers have had the means to notice them. Many smaller space rocks have been spotted much closer, even inside the orbit of the Moon.

NASA scientists and other asteroid experts have been watching Toutatis for more than a decade, and though its orbit changes slightly with each 4-year trip around the Sun, they have a good handle on the path.

The position of the asteroid on this pass is known to a precision roughly equal to the rock's size, said Alan Harris, a senior research scientist at the Space Science Institute. That leaves a little wiggle room for its exact location at closest approach, but not much.

"Because of the nature of the orbit, we cannot predict thousands of years into the future for this object, but in anyone's lifetime now, there is no chance" of an impact, Harris told SPACE.com.

Spotting Toutatis

Toutatis will not be visible to the unaided eye. Experienced telescope users can see it now from the Southern Hemisphere, and in early October it will be visible from the north.

Finding Toutatis will be challenging, Harris said, due to a combination of the asteroid's position in the sky and interfering moonlight.

Because the asteroid is so close, its location in the sky will vary significantly for skywatchers in different places on Earth at any given moment. And because it moves quickly, the location changes constantly. Printed sky maps struggle to provide enough detail to be useful.

"In a large telescope the motion would be perceptible against any stars in the field more or less in real time, sort of like watching the second hand on a clock," Harris said, adding that the movement would be "not quite that fast, but noticeable."

Highly experienced observers will use complex plotting information known as ephemeris data. Others can use software programs that generate maps for specific times and locations.

When, where and how

At its closest on Sept. 29, Toutatis will be visible only to observers in the Southern Hemisphere.

Large and steady binoculars will be able to pick out the pinprick of sunlight reflecting off the asteroid, providing observers "use a good program like Starry Night Pro to plot its incredibly rapid motion across the sky," said Clay Sherrod of the Arkansas Sky Observatory. (The software company Starry Night is owned by Imaginova, parent also of SPACE.com.)

Soon thereafter, experienced backyard astronomers north of the equator will have a chance to find Toutatis.

"By early October, it will suddenly be re-emerging into northern skies as its apparent trajectory will bring it back into very favorable view," Sherrod said in an e-mail interview. But by then the asteroid will be moving away from Earth and getting dimmer. It will quickly become "very difficult" to spot even with an 8-inch telescope, he said.

Sherrod photographed the giant space rock last week (it was visible then in the north through large telescopes) and said exposures longer than eight seconds showed a trail as the giant rock moved slightly against the background of stars.

"It has been quite a wonderful show so far," he said.

Strange rock indeed

Asteroid Toutatis was discovered in 1989. Scientists have modeled its strange rotation and odd shape -- it looks something like a pockmarked dumbbell -- on previous flybys.

Instead of a fixed north pole, Toutatis' axis of rotation wanders in two separate cycles of 5.4 and 7.3 Earth-days. So while most asteroids rotate somewhat like a football thrown in a perfect spiral, "Toutatis tumbles like a flubbed pass," says Scott Hudson of Washington State University.

Astronomers will use this week's flyby to examine Toutatis in greater detail, with a goal of pinning down the rock's rate of spin and better estimating its future path.

While some rumors have suggested the asteroid's forecasted course might be off by enough to cause a collision with Earth, Sherrod agrees with Harris and other scientists that there is no chance for calamity. Sherrod has been monitoring Toutatis' movement since July 3, logging more than 500 observations that allow mapping of a precise trajectory.

"Although the actual path of it has indeed varied a slight bit from the original calculated, there is absolutely no chance of a physical encounter or impact with Earth," he said.

• Mysteries of Toutatis
• Video of Toutatis Tumbling
• Starry Night Software: Map Toutatis from your location
• Ephemeris information for experienced observers from NASA

Starry Night software brings the universe to your desktop. Map the sky from your location, or just sit back and let the cosmos come to you.