Reference Pages
30 November 2012, 12:14 PM ET
Discovered in 1781, the seventh planet was destined to cause snickers whenever someone says its name.
28 November 2012, 12:41 PM ET
The Chandra X-Ray Observatory has probed the origins of dark matter and revealed much about the parts of the universe we can't see visually.
27 November 2012, 01:10 PM ET
Mercury is the smallest planet, but it is very dense.
27 November 2012, 12:53 PM ET
Mercury is the sun's closest planet, but it has a bizarre orbit.
27 November 2012, 12:44 PM ET
Despite being closest to the sun, Mercury is not the hottest planet.
27 November 2012, 12:26 PM ET
The solar wind blasts the closest planet to the sun, leaving it with the thinnest atmosphere of all the planets.
27 November 2012, 12:14 PM ET
Mercury is a terrestrial planet with a rocky surface and metallic core.
27 November 2012, 12:03 PM ET
The smallest planet collected material from the solar nebula.
26 November 2012, 04:55 PM ET
Galileo was the first space probe to spend years observing the planet Jupiter and its moons
20 November 2012, 01:29 PM ET
Pluto is two-thirds as big as Earth's moon.
20 November 2012, 01:20 PM ET
The distance to Pluto changes because of the dwarf planet's odd orbit.
20 November 2012, 01:02 PM ET
Yes. Scientists think Pluto's atmosphere is mostly nitrogen.
20 November 2012, 12:51 PM ET
Pluto is one of the coldest bodies in the solar system.
20 November 2012, 12:37 PM ET
The dwarf planet is composed of rocky material and a great deal of ice.
20 November 2012, 12:31 PM ET
The dwarf planet formed a bit differently from the rest of the solar system.
19 November 2012, 04:52 PM ET
To this day, the photos taken by the Soviet spacecraft are the best we have from the cloudy planet.
16 November 2012, 06:41 PM ET
Venus is slightly smaller than Earth.
16 November 2012, 06:34 PM ET
Venus is the closest planet to Earth.
16 November 2012, 06:23 PM ET
The atmosphere of Venus is thick with clouds of carbon dioxide.
16 November 2012, 06:15 PM ET
Venus is the hottest planet in the solar system.
16 November 2012, 06:05 PM ET
Venus, like Earth, is a rocky planet, but it has a smooth surface.
16 November 2012, 05:54 PM ET
Venus was made at the very beginning of the solar system after the solar nebula collapsed.
16 November 2012, 02:00 AM ET
Watching a meteor shower on a clear, dark night is an unforgettable experience.
15 November 2012, 02:09 PM ET
The Solar and Heliospheric Observatory (SOHO) satellite keeps watch over sunspots and other solar events.
14 November 2012, 01:10 PM ET
Saturn is the second largest planet in the solar system.
14 November 2012, 12:50 PM ET
Saturn is the farthest planet you can see with the naked eye.
14 November 2012, 12:44 PM ET
The gas giant is mostly atmosphere; it lacks a solid surface.
14 November 2012, 12:25 PM ET
Most of ringed planet's heat comes from within, rather than from the sun.
14 November 2012, 12:20 PM ET
The gas giant is mostly hydrogen and helium.
14 November 2012, 12:12 PM ET
Saturn was made, along with the other planets, out of the cloud of dust and gas known as the solar nebula.
12 November 2012, 12:41 PM ET
Mariner 9 changed our perceptions of the Red Planet.
08 November 2012, 04:55 PM ET
The mission rebooted NASA's exploration of the Red Planet, and launched a new strategy for building spacecraft.