Reference Pages
15 August 2013, 06:33 PM ET
Elliptical galaxies are dim collections of older stars, so they don't shine as brightly as spiral galaxies.
15 August 2013, 12:01 AM ET
A spiral galaxy has a distinct winding shape. Most of the galaxies observed by astronomers are spiral galaxies.
02 August 2013, 02:02 PM ET
Triton has some peculiarities about its environment, including the fact that it orbits backward to Neptune's rotation and seems to have undergone a huge melt in the past.
02 August 2013, 02:00 PM ET
Scientists have found moons of Neptune as late as 2013, a quarter-century after Voyager 2 was the first and last spacecraft to swing through the system.
01 August 2013, 07:12 PM ET
Solar wind is a constant stream of plasma and particles emanating from the sun.
01 August 2013, 01:46 AM ET
Uranus has 27 known moons discovered through telescopes as well as the Voyager 2 mission to the planet in 1986.
31 July 2013, 01:26 AM ET
Neutron stars are city-size objects that pack quite a punch.
24 July 2013, 11:39 PM ET
The Lunar Reconnaissance Orbiter has uncovered extensive evidence of water on the moon.
23 July 2013, 04:59 PM ET
SDO provides insights on the structure of the sun's magnetic field, as well as how energy is transferred from the sun into space.
22 July 2013, 08:15 PM ET
Pollux, one of the main stars in Gemini, is bright and easy to find in the night sky. More recently, scientists found a planet orbiting the star.
20 July 2013, 04:24 AM ET
Spica is a bright binary star system in the Virgo constellation.
18 July 2013, 09:28 PM ET
Aldebaran is a prominent star in Taurus that is sometimes used for comparative astronomy.
18 July 2013, 04:14 AM ET
Betelgeuse is well-known because of its bright size and easy-to-spot location in the constellation Orion. It is of astronomical interest because it will likely go supernova in less than a million years.
16 July 2013, 08:06 PM ET
Capella is a binary star easily visible in the northern night sky for much of the year.
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, 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.