Reference Pages
24 December 2013, 12:36 AM ET
Based on what we can observe, the universe appears to be almost 28 billion light-years in diameter. However, it is far larger than that.
20 December 2013, 06:21 PM ET
The universe is approximately 13.8 billion years old.
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, 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.
24 September 2013, 05:03 PM ET
Procyon is a binary system, with a main-sequence larger star and a smaller white dwarf star orbiting each other.
23 September 2013, 08:24 PM ET
Deneb, one of the three stars of the Summer Triangle, anchors the tail of Cygnus the Swan.
20 September 2013, 09:29 PM ET
Regulus is a bright star in the northern sky that has at least two known stellar companions.