Welcome to Planet Earth
31.01.1999

Welcome to Planet Earth, the third planet from a star named the Sun. The Earth is shaped like a sphere and composed mostly of rock. Over 70 percent of the Earth's surface is water. The planet has a relatively thin atmosphere composed mostly of nitrogen and oxygen.

Lenticular Clouds Over Washington
4.11.2012

Are those UFOs near that mountain? No -- they are multilayered lenticular clouds. Moist air forced to flow upward around mountain tops can create lenticular clouds. Water droplets condense from moist air cooled below the dew point, and clouds are opaque groups of water droplets.

Ship Tracks over the Pacific Ocean
8.06.2022

What are those unusual streaks? Some images of planet Earth show clear bright streaks that follow the paths of ships. Known as ship tracks, these low and narrow bands are caused by the ship's engine exhaust.

Magnified Mars
6.02.2004

At first glance, this sharp, color close-up gives the strong impression of pebbles strewn over a sandy beach. But the picture is one of the first microscopic images of another planet, captured by the Opportunity rover on its tenth sol on the martian surface at Meridiani Planum.

The Gullies Of Mars
23.06.2000

The recently revealed gullies on Mars are rare. But they may prove to be sites of present day, near surface, liquid water, holding out the tantalizing possibility of martian life. Too small to have...

Martian Crater Shows Evidence of Dried Pond
3.06.1998

Did a pond once exist in this Martian crater? Recent photographs by the spacecraft Mars Global Surveyor, currently in orbit around Mars, show features unusual for Mars yet similar to a dried pond on Earth.

Unusual Bright Soil on Mars
6.04.2006

What is this bright soil on Mars? Several times while rolling across Mars, the treads of the robotic rover Spirit have serendipitously uncovered unusually bright soil. Spirit uncovered another batch unexpectedly last month while rolling toward its winter hibernation location on McCool Hill.

A Martian River Bed
5.02.1998

This canyon on the surface of Mars appears to have been carved by flowing water. Known as Nanedi Vallis, the terraces and channels visible within the canyon strongly suggest that a river of water once ran here.

Oceans Under Jupiter's Europa?
9.04.1997

Is there life beneath Europa? Today, new results are being announced (at about 2 pm EST) about the possibility of oceans under Jupiter's moon Europa. The existence of such oceans increases the likelihood that some sort of life exists beneath the fractured ice planes of Jupiter's smoothest satellite.

Phoenix Rises Toward Mars
8.08.2007

Can Mars sustain life? To help answer this question, last week NASA launched the Phoenix mission to Mars. In May 2008, Phoenix is expected to land in an unexplored north polar region of Mars that is rich in water-ice.