Reference Pages
20 December 2013, 06:21 PM ET
The universe is approximately 13.8 billion years old.
12 December 2013, 07:10 PM ET
Find out the current moon phases. The moon cycles through eight phases every month.
12 December 2013, 10:40 AM ET
The full moon happens once a month. Find out when.
11 December 2013, 09:30 AM ET
Comet ISON, discovered by two amateur astronomers in Russia, arrived in Earth's neighborhood in November 2013 and apparently broke up as it rounded the sun.
03 December 2013, 06:22 PM ET
Gliese 581g is an extra-solar planet that was discovered in 2010, but quickly cast into doubt by other studies. The original discoverers then published a follow-up paper in 2012 defending their find.
02 December 2013, 01:53 PM ET
A black dwarf is all that is left after a white dwarf star burns off all of its heat, but retains its mass.
02 December 2013, 01:49 PM ET
Brown dwarfs never burn fusion at their core, so scientists sometimes refer to them as "failed stars."
27 November 2013, 11:18 PM ET
Most of the star nearest to Earth are red dwarfs, but they are too dim to be seen with the naked eye.
26 November 2013, 06:11 PM ET
Most stars in the universe will eventually burn off all of their hydrogen and become dead husks called white dwarfs.
25 November 2013, 04:46 PM ET
Shaula, the 24th-brightest star, is a possible multiple-star system in the constellation Scorpius.
22 November 2013, 06:36 PM ET
Gacrux is a variable star that blows strong winds through its system.
21 November 2013, 12:24 AM ET
Beta Crucis is a possible multiple star system in the Southern Cross.
15 November 2013, 05:24 PM ET
NASA's newest Mars probe is expected to study the atmosphere of the Red Planet in amazing new detail.
13 November 2013, 05:10 PM ET
A simple planetarium can be built out of corrugated cardboard.
12 November 2013, 11:55 PM ET
Achernar, the ninth-brightest star, is a binary system, with one of the stars rotating extremely quickly.
11 November 2013, 09:58 PM ET
Rigel Kentaurus (better known as Alpha Centauri) is in the closest star system to Earth and is one of the brightest stars in our sky.
30 October 2013, 01:36 AM ET
The Quadrantids are a meteor shower in January that peak for only about six hours, are named for a constellation that no longer exists and come from an asteroid rather than a comet.
28 October 2013, 04:25 PM ET
The Eta Aquarids are a meteor shower best visible from the Southern Hemisphere.
23 October 2013, 06:47 PM ET
The Lyrid meteor shower has been observed for more than 2,700 years.
22 October 2013, 04:56 PM ET
The Leonids take place every year in November. Once a generation, it is possible for a storm of meteors to occur with a peak of about 1,000 an hour – or even more.
21 October 2013, 07:15 PM ET
The Geminids come from an asteroid, 3200 Phaethon, but scientists are still trying to figure out exactly how it sheds enough debris to produce the bright meteor shower.
21 October 2013, 04:05 AM ET
The Orionid meteor shower, made up of remnants of Halley's Comet, peaks in mid-October.
16 October 2013, 05:54 PM ET
The rings of Saturn are made of billions of particles, from tiny grains to giant chunks.
08 October 2013, 07:29 PM ET
Makemake was the fourth dwarf planet named. It was one of the bodies that caused Pluto to lose its status as a planet.
04 October 2013, 08:44 PM ET
Haumea, the fifth body in the solar system to be classified as a dwarf planet, spins faster than any other known large body in the solar system.
03 October 2013, 03:58 PM ET
The Perseids meteor shower arises out of the debris of Comet Swift-Tuttle, which last made a pass by Earth in 1992.
01 October 2013, 06:35 PM ET
Acrux is made up of three stars, and a possible fourth that lies close by.
30 September 2013, 09:07 PM ET
Weightlessness, or the absence of gravity, has several short-term and long-term effects on astronauts.
27 September 2013, 05:09 PM ET
Adhara is a bright binary star in Canis Major that shows up best in ultraviolet light.
27 September 2013, 01:39 AM ET
Hadar is a binary-star system in the Southern Hemisphere. Its stars may go supernova in the future.
26 September 2013, 05:04 PM ET
Mars has water trapped in the polar ice caps. More water may lie just beneath the surface.
26 September 2013, 01:04 AM ET
Fomalhaut has a planet that rose from the dead, as well as a vast number of comets that crash into each other daily.