Monday, April 2, 2012: Four of five sounding rockets liftoff from NASA's Wallops Flight Facility (Virginia) in this time-lapse photograph of the ATREX mission. The experiment took place on March 27, 2012, producing white clouds to study fast-moving winds high in the thermosphere. The first rocket was launched at 4:58 am EDT, with following launches occurring at 80-second intervals. The star trails result from the extended exposure. [See our full story.]
— Tom Chao
Tuesday, April 3, 2012: Galaxy M95, in the Leo I galaxy group, surprised skywatchers recently with a new supernova. Astronomers discovered SN 2012aw on March 16, 2012. Here, it lies at in the spiral arm that descends from the top to the lower right of the galaxy.
— Tom Chao
Wednesday, April 4, 2012: NASA's Robert R. "Bob" Meyer, Jr. recently retired after 40 years as an aerospace engineer, project manager and program manager with NASA, mainly at NASA's Dryden Flight Research Center in Southern California. His last six years were as program manager of the Stratospheric Observatory for Infrared Astronomy, or SOFIA. Here, Meyer (left), also a pilot, and Ed Schneider humorously displayed "cheesehead" hats after showing off one of Dryden's now-retired SR-71 Blackbird aircraft at the Experimental Aircraft Association's convention in Oshkosh, Wisconsin in 1997.
— Tom Chao
Thursday, April 5, 2012: A United Launch Alliance Delta4 rocket carrying the NROL-25 spy satellite for the National Reconnaissance Office lifts off from Vandenberg Air Force Base in California on April 3, 2012.
— Tom Chao
Friday, April 6, 2012: ESA astronaut André Kuipers took this photo of the coast of North Africa and the Mediterranean Sea from the International Space Station on March 31, 2012. It was released during Earth Hour, a worldwide effort to raise awareness of sustainability issues by encouraging people to turn off their electric lights for an hour.
— Tom Chao
Monday, April 9, 2012: Planetary nebula Abell 33, which appears as an almost circular disk to Earth observers, lies in the constellation of Hydra. A bright star coincidentally sits on its rim.
— Tom Chao
Tuesday, April 10, 2012: The STEREO spacecraft recorded this still image of a solar coronal mass ejection during a week of heavy activity, March 25-April 2, 2010. In the image, the sun lies just beyond the left edge, and the Earth millions of miles to the right. Mercury is the bright spot slightly left of and below the center of the image.
— Tom Chao
Wednesday, April 11, 2012: NGC 4980, a spiral galaxy, lies in the southern constellation of Hydra. The galaxy’s slight deformation usually would be attributed to recent tidal interactions with another galaxy, however no other galaxies exist nearby. Although the galaxy’s spiral structure remains difficult to discern in this image, scientists showed that NGC 4980 has a disc-type bulge, and its rotating spiral structure extends to the center of the galaxy. Image released April 2, 2012.
— Tom Chao
Thursday, April 12, 2012: Chains of pits in the Tharsis region of Mars appear in this computer-generated perspective view. Data gathered by the High-Resolution Stereo Camera (HRSC) on ESA's Mars Express spacecraft provided the basis for the image. If any cave-like structures are associated with the pits, they could have harbored hypothesized microorganisms in the past. Image taken June 22, 2011.
— Tom Chao
Friday, April 13, 2012: The mate-demate device frames the Shuttle Carrier Aircraft (NASA 905), which arrived at Kennedy Space Center on April 10, 2012. The modified Boeing 747 jet airliner will ferry shuttle Discovery to its final home at the Smithsonian's National Air and Space Museum Steven F. Udvar-Hazy Center in Chantilly, Va. on April 17, 2012.
— Tom Chao
Monday, April 16, 2012: Saturn's moon Mimas casts a ghostly shadow on the southern hemisphere of Saturn at the lower left of this photograph taken by Cassini spacecraft on Jan. 21, 2012. Shadows of the rings fall on Saturn at the upper right. Cassini took the photo approximately 1.6 million miles (2.6 million kilometers) from Saturn, looking toward the southern, unilluminated side of the rings from about 1 degree below the ringplane.
— Tom Chao
Tuesday, April 17, 2012: Globular cluster Messier 70 experienced a core collapse in the past, meaning that even more stars squeeze into the object's core than on average, such that the brightness of the cluster increases steadily towards its center. Messier 70 orbits close to the center of the Milky Way, about 30 000 light-years away from the Solar System. Image released April 13, 2012.
— Tom Chao
Wednesday, April 18, 2012: Space shuttle Discovery, atop a NASA 747 Shuttle Carrier Aircraft, flies near the U.S. Capitol, Tuesday, April 17, 2012, in Washington, D.C. NASA will transfer Discovery to the Smithsonian Institution’s National Air and Space Museum, where it will remain on display. The two people on top of the Capitol dome had the best view of all!
— Tom Chao
Thursday, April 19, 2012: Saturn's icy moon Enceladus floats below the gas giant's rings while another moon, Titan, lurks in the background, in this image taken by the Cassini spacecraft on March 12, 2012.
— Tom Chao
Friday, April 20, 2012: The Atacama Pathfinder Experiment (APEX) telescope looks skyward during a moonlit night on Chajnantor Plateau in Chile, one of the highest and driest observatory sites in the world. On the left shines the tail of the constellation of Scorpius, the Scorpion. Across the sky stretches the plane of the Milky Way. Elsewhere in this photo, one can see the constellation of Sagittarius, The Archer, looming over APEX’s dish. Also, Messier 7 (AKA Ptolemy’s Cluster), Messier 6 (the Butterfly Cluster), and the Lagoon Nebula all appear here. Image released April 16, 2012.
— Tom Chao
Monday, April 23, 2012: Auroramax, an automated camera that photographs auroras in Canada, took this photo. It tweeted: "Latest image of aurora borealis above Yellowknife, NWT taken at 00:49 MDT on April 17, 2012."
— Tom Chao
Tuesday, April 24, 2012: In May 2010, about one Martian year ago, this area of Mars showed distinct tracks of boulders that had rolled down the slopes (from right to left in this image), exposing darker dust underneath the lighter surface material. Now, this follow-up image from February 2012 shows the smaller dark tracks have disappeared, and the larger ones are much less visible. A likely explanation suggests that atmospheric dust falls on the region, again covering the markings.
— Tom Chao
Wednesday, April 25, 2012: 9-year-old Caine Monroy (right) receives a personal guided tour of the Jet Propulsion Laboratory in Pasadena, Calif., from JPL scientist Robert Manning. Caine rocketed to extraordinary levels of internet stardom when a documentary about his handmade arcade of packing boxes and tape ("Caine’s Arcade") went viral online. Caine's Arcade official Facebook page remarks: "Robert Manning used to make cardboard rockets when he was Caine's age, now he makes real ones." Manning is Flight System Chief Engineer for the NASA's Mars Pathfinder mission. The meeting took place January 23, 2012, before Caine's Arcade became a sensation, as Manning saw a rough cut of the film in November 2011, according to LA Weekly.
— Tom Chao
Thursday, April 26, 2012: This amazing panorama depicts the site of ALMA, the Atacama Large Millimeter/submillimeter Array, in the Chilean Andes. When ALMA is complete, it will have 54 of the 12-meter-diameter dishes shown. Above the array, the arc of the Milky Way glistens while the moon bathes the scene in an eerie light. ESO Photo Ambassador Stéphane Guisard took the shot, released April 23, 2012. Click the picture to see a larger version of the astounding image.
— Tom Chao
Friday, April 27, 2012: The brownish "blobs" floating at the upper right of this Hubble Space Telescope image are known as dark molecular clouds. The energy of light and winds from nearby stars break apart the dark dust grains that make the forms — reminiscent of painted words by artist Ed Ruscha — opaque, thus making them disappear. The Great Nebula in Carina lies about 7,500 light years away, toward the constellation of Keel (Carina).
— Tom Chao
Monday, April 30, 2012: Giant blue stars ionizing hydrogen gas give dwarf galaxy IC 10 its signature blue glow, and signal ongoing star formation. IC 10 is one of tens of dwarf galaxies in our Local Group, which is dominated by the giant Milky Way (our galaxy) and Andromeda Galaxy.
— Tom Chao
For older Image of the Day pictures, please visit the Image of the Day archives. Above: NGC 2467.
