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.
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.
07 November 2012, 06:24 PM ET
Jupiter is about 318 times as big as Earth.
07 November 2012, 06:10 PM ET
On Jupiter, temperature is dependent on the planet's interior, not the sun.
07 November 2012, 05:51 PM ET
Like all of the planets, Jupiter was formed out of the solar nebula.
07 November 2012, 05:17 PM ET
Jupiter is composed of gases — hydrogen and helium, mostly.
07 November 2012, 04:33 PM ET
The atmosphere of Jupiter has distinctive belts, bands and a massive swirling storm.
07 November 2012, 04:07 PM ET
The distance to Jupiter from Earth varies because of the planets' elliptical orbits.
31 October 2012, 01:52 PM ET
The Mariner 10 spacecraft gave us the first close-up view of the sun's closest planet.
26 October 2012, 12:10 PM ET
The Viking mission to Mars gave scientists their first look at the Martian landscape.
23 October 2012, 02:40 PM ET
The space shuttle Discovery flew 39 times into space, more than any spacecraft.
22 October 2012, 07:25 PM ET
The surface of the moon experiences great extremes in temperature, from boiling hot to freezing cold.
19 October 2012, 02:03 PM ET
The moon is about one-fourth as big as Earth, relatively large for a planet's satellite.