Reference Pages
18 July 2014, 01:31 AM ET
Mount Wilson Observatory is a Los Angeles-area facility with several telescopes open to astronomers and the public.
01 July 2014, 09:48 AM ET
This month's night sky is full of cosmic wonders including planets and other celestial objects galore. Find out what's up in your night sky and how to see it in this stargazing guide.
28 June 2014, 01:10 AM ET
The twin telescopes at the W.M. Keck Observatory are the largest optical and infrared telescopes in the world. The telescopes are located atop Mauna Kea, a dormant volcano in Hawaii.
20 June 2014, 03:11 AM ET
The Palomar Observatory is an astronomical research center where several small worlds were discovered near the edge of the solar system.
12 June 2014, 01:02 AM ET
Astrophysics is a branch of space science that applies the laws of physics and chemistry to seek to understand the universe and our place in it.
11 June 2014, 04:28 AM ET
Chuck Yeager was an American test pilot who was the first person to break the sound barrier — the point where a speeding object (such as an airplane) passes the speed of sound.
31 May 2014, 03:54 AM ET
The exact number of stars is impossible to know because we aren't sure how big the universe is.
29 May 2014, 12:39 AM ET
Grasshopper was a reusable rocket prototype tested by the company SpaceX in preparation for more ambitious launches.
22 May 2014, 09:28 PM ET
Many astronomers define a planet as an object that orbits the sun (but not another object), is round (or nearly so) and has cleared the area around its orbit.
21 May 2014, 11:10 AM ET
Astronomers have several ways to count stars, but getting a definitive answer to how many there are in a galaxy is "surprisingly difficult."
09 May 2014, 03:11 AM ET
Quaoar is a planetoid that lies in the Kuiper Belt, a region of space beyond Pluto that is filled with icy bodies.
07 May 2014, 10:10 PM ET
Ikaros is a Japanese spacecraft that was the first to successfully use a solar sail at some distance from Earth.
07 May 2014, 01:44 AM ET
Do you have the right stuff? Becoming an astronaut doesn't just happen overnight. It takes many years of education and experience to meet the basic qualifications.
05 May 2014, 10:00 AM ET
The astronaut was also the fifth man to walk on the moon.
03 May 2014, 03:53 AM ET
Astronomers use many terms to describe what happens during an eclipse, and this glossary shows some of the more common things they say.
02 May 2014, 03:32 AM ET
Redshift and blueshift describe how light changes as objects in space move closer or farther away from us.
01 May 2014, 01:22 AM ET
Comet C/2011 W3 Lovejoy is a comet on its way to the outer solar system. It survived a close brush with the sun in December 2011. It is one of four comets discovered by amateur astronomer Terry Lovejoy.
30 April 2014, 12:00 PM ET
Total solar eclipses are one of nature’s grandest events. What is a total solar eclipse? How do they work? And when is the next one? We explain.
30 April 2014, 11:00 AM ET
Lunar eclipses occur when Earth's shadow blocks the sun. There are three types: The most dramatic is a total lunar eclipse. Find out when is the next one.
30 April 2014, 02:22 AM ET
Sedna is a dwarf planet that is one of the most distant bodies found in our solar system.
23 April 2014, 01:58 AM ET
Guion "Guy" Bluford is a former NASA astronaut who was the first African-American to fly into space. He flew four shuttle missions.
22 April 2014, 02:24 AM ET
The Triangulum Galaxy (M33) that is about 3 million light-years away from Earth. Among its most distinctive features are ionized hydrogen clouds, which are massive regions of starbirth.
17 April 2014, 01:10 AM ET
The Atacama Large Millimeter/submillimeter Array (ALMA) is a telescope array that peers through stardust to see planetary systems under construction.
16 April 2014, 01:50 AM ET
The Sombrero Galaxy, also called M104 or NGC 4594, is about 28 million light-years from our planet in the constellation Virgo. It is so named because the halo surrounding its disc is unusually large, making it look like a sombrero.
15 April 2014, 01:29 AM ET
The Whirlpool Galaxy is a spiral galaxy that is relatively close to Earth — about 30 million light-years away.
11 April 2014, 01:10 AM ET
The Large Magellanic Cloud (LMC) is a satellite dwarf galaxy that is among the closest galaxies to Earth.
02 April 2014, 04:19 AM ET
Where are the aliens? That is the question that the Fermi Paradox seeks to answer. Given our solar system's relatively young age, the theory says that aliens should have visited us already.
01 April 2014, 02:18 AM ET
Astronomers say there are 100 billion to 200 billion galaxies in the universe. But accurately counting the number of galaxies depends on several factors.
28 March 2014, 05:35 PM ET
A look at the U.S. Air Force's unmanned X-37B space plane, which has flown three secret, long-duration missions in Earth orbit to date.
26 March 2014, 03:55 AM ET
The Drake Equation is used to estimate the number of communicating civilizations in the cosmos, or more simply put, the odds of finding intelligent life in the universe.
21 March 2014, 11:31 PM ET
The Hubble Constant is the unit of measurement used to describe the expansion of the universe. The cosmos has been getting bigger since the Big Bang kick-started the growth about 13.82 billion years ago.
19 March 2014, 12:59 AM ET
The Big Bang Theory is the leading explanation about how the universe began.