Reference Pages
13 July 2013, 11:40 AM ET
Several men laid claim to inventing the telescope, but the credit usually goes to Hans Lippershey, a Dutch lensmaker, in 1608.
11 July 2013, 10:11 PM ET
Castor, part of the constellation Gemini, is revealed as six stars under telescopic observations.
10 July 2013, 11:08 PM ET
Everything you need to know about NASA's Big Bang-probing space telescope.
09 July 2013, 09:28 PM ET
Antares is a red supergiant that one day will explode into a supernova.
29 June 2013, 07:41 AM ET
The space shuttle Atlantis was the unsung workhorse of the shuttle fleet.
27 June 2013, 06:14 PM ET
Ophiuchus is a fairly large and rambling constellation, but it is one of the least well-known.
26 June 2013, 06:49 PM ET
Altair is just 16.7 light-years from Earth, making it one of the closest naked-eye stars visible in the sky.
25 June 2013, 06:34 PM ET
Vega, historically one of the most-studied stars, is under scrutiny in modern times because it may have planets.
24 June 2013, 06:07 PM ET
Sirius was known by the ancients, but a faint companion was not discovered until 1862.
21 June 2013, 06:40 PM ET
Scientists say a giant impact knocked off the raw ingredients for the moon off the primitive molten Earth and into orbit. SPACE.com has an overview of Earth’s Moon, including its composition and orbit.
21 June 2013, 03:07 PM ET
Traveling through time — possible in theory — is beyond our current technological capabilities.
21 June 2013, 01:47 PM ET
A trip to the moon takes about three days to travel more than 250,000 miles.
20 June 2013, 02:59 PM ET
This large constellation contains the most stars with known planets. It is the 15th largest constellation overall.
19 June 2013, 07:26 PM ET
The brightness of a star is measured several ways: how it appears from Earth, how bright it would appear from a standard distance and how much energy it emits.
17 June 2013, 05:21 PM ET
This faint constellation is the only one named for an inanimate object.
14 June 2013, 03:48 PM ET
Valentina Tereshkova was the first woman to go into space. She flew Vostok 6 in 1963, spending almost three days in space and orbiting Earth 48 times.
10 June 2013, 06:38 PM ET
Aquarius is best viewed in the fall. The constellation's stars are not very bright.
05 June 2013, 07:39 PM ET
Pisces is one of the largest constellations, and also one of the faintest.
03 June 2013, 05:24 PM ET
Also known as Capricorn, this is one of the faintest constellations.
24 May 2013, 06:34 PM ET
Griffith Observatory is dedicated to astronomy education for the general public, and allows ordinary folks to get a peek through its telescopes.
22 May 2013, 05:28 PM ET
Texas' McDonald Observatory is embarking on a search for dark energy.
15 May 2013, 04:01 PM ET
More than 800 extrasolar planets have been discovered.
13 May 2013, 01:10 PM ET
The sun's unceasing activity affects our planet beyond providing obvious light and heat.
06 May 2013, 03:28 PM ET
Arecibo Observatory has been used to send a SETI message as well as for scanning the skies for approaching asteroids.
01 May 2013, 06:03 PM ET
Dark matter emits no light, and cannot be directly observed, but scientists think that it and dark energy make up most of the mass of the universe.
01 May 2013, 05:55 PM ET
Dark energy is a mysterious quantity that makes up, along with dark matter, most of the mass of the universe.
30 April 2013, 07:14 PM ET
The world's time zones and hemispheres are divided into east and west by the prime meridian at the Royal Observatory in Greenwich.
29 April 2013, 05:41 PM ET
A wormhole is a theoretical passage through space-time that could create shortcuts for long journeys across the universe.
26 April 2013, 04:32 PM ET
Lowell Observatory is best known for the discovery of Pluto. Astronomers there have also studied Halley's Comet and discovered an exoplanet in 2007.
25 April 2013, 04:39 PM ET
After years competing in spaceflight, the United States and the Soviet Union did a joint mission for the first time in 1975.
24 April 2013, 03:33 PM ET
The moons of Saturn — 62 in all — come in a variety of sizes and compositions.
24 April 2013, 07:13 AM ET
Since launch in 1990, the Hubble Space Telescope (HST) has provided amazing images that have led to discoveries. Explore Hubble's history and facts.