Orion's Star Colors
1.12.1996

What determines a star's color? Its temperature. Red stars are cool, with temperatures of around 3,000 degrees Kelvin (K), while blue stars are hotter and can have temperatures over 30,000 degrees K. Our own lovely yellow Sun's temperature is a comforting 6,000 degrees K.

Asteroid 253 Mathilde's Large Craters
1.07.1997

You're zipping through the Solar System when you pass ... asteroid 253 Mathilde. This actually happened to NASA's NEAR spacecraft just last Friday. The above picture of the previously unresolved asteroid was released just yesterday.

A Sun Halo Over Tennessee
8.03.2005

Sometimes it looks like the Sun is being viewed through a large lens. In the above case, however, there are actually millions of lenses: ice crystals. As water freezes in the upper atmosphere, small, flat, six-sided, ice crystals might be formed.

The Solar Wind Emerges
7.02.1999

Winds of fast particles blow out from the Sun, but why? Astronomers came a step closer to answering this question recently by making detailed observations of the high-speed wind source with the space-borne Solar and Heliospheric Observatory (SOHO).

Stars of the Galactic Center
12.01.2006

The center of our Milky Way Galaxy is hidden from the prying eyes of optical telescopes by clouds of obscuring dust and gas. But in this stunning vista, the Spitzer Space Telescope's infrared cameras, penetrate much of the dust revealing the stars of the crowded galactic center region.

Stars of the Galactic Center
9.02.2007

The center of our Milky Way Galaxy is hidden from the prying eyes of optical telescopes by clouds of obscuring dust and gas. But in this stunning vista, the Spitzer Space Telescope's infrared cameras, penetrate much of the dust revealing the stars of the crowded galactic center region.

Earthrise from Moon Orbiting Kaguya
19.11.2007

What does the Earth look like from the Moon? A new version of this space age perspective was captured by the robotic Kaguya spacecraft currently in orbit around Earth's Moon. Launched two months...

Shadow of a Martian Robot
29.06.2008

What if you saw your shadow on Mars and it wasn't human? Then you might be the Opportunity rover currently exploring Mars. Opportunity and sister robot Spirit have been probing the red planet since early 2004, finding evidence of ancient water, and sending breathtaking images across the inner Solar System.

Layered Hills in Arabia Terra on Mars
15.08.2010

Why are some hills on Mars so layered? The answer is still under investigation. Clearly, dark windblown sand surrounds outcropping of light sedimentary rock across the floor of crater Arabia Terra. The light rock clearly appears structured into many layers, the lowest of which is likely very old.

Fifth Moon Discovered Orbiting Pluto
16.07.2012

A fifth moon has been discovered orbiting Pluto. The moon was discovered earlier this month in images taken by the Hubble Space Telescope in preparation for the New Horizons mission's scheduled flyby of Pluto in 2015.