Ice Clouds over Mars
13.10.1997

Mars has clouds too. The above true color image taken in August by Mars Pathfinder shows clouds of ice high in the Martian atmosphere. Unlike Earth's atmosphere which is composed predominantly of nitrogen and oxygen, Mars' atmosphere is composed mostly of carbon dioxide.

A Huge Impact Crater on Mars
3.02.1996

What hit Mars? The impact crater Schiparelli near the center of the above image was likely caused by a collision with an object the size of an asteroid. Also evident in this full face mosaic of Mars are numerous craters from many other impacts with smaller objects over billions of years.

Spring Dust Storms at the North Pole of Mars
24.12.2002

Spring reached the north pole of Mars in May, and brought with it the usual dust storms. As the north polar cap begins to thaw, a temperature difference occurs between the cold frost region and recently thawed surface, resulting in swirling winds between the adjacent regions.

Layers of the Martian South Polar Cap
25.04.2000

The South Pole of Mars is stranger than was previously thought. Pictured above are unexpectedly complex layers photographed recently by the Mars Global Surveyor spacecraft currently orbiting Mars. The layers probably include carbon dioxide ice, water ice, rock and dust.

The Dunes Of Mars
14.08.1998

The North Pole of Mars is ringed by a "sea of sand dunes". For Mars' Northern Hemisphere, Spring began in mid July and increased sunlight is now shrinking the polar cap revealing the wind-swept dunes to the cameras onboard the Mars Global Surveyor spacecraft.

All of Mars
10.02.1998

Mars Global Surveyor is photographing Mars. The robot spacecraft arrived last September and continues to use solar panel aerobraking to help maneuver it to a better orbit to survey all of Mars The above image is a reconstruction of several photographs digitally combined to simulate a single vantage point 2700 kilometers above the Martian surface.

Sand Dunes Thawing on Mars
3.03.2008

What are these strange shapes on Mars? Defrosting sand dunes. As spring now dawns on the Northern Hemisphere of Mars, dunes of sand near the pole, as pictured above, are beginning to thaw. The carbon dioxide and water ice actually sublime in the thin atmosphere directly to gas.

Swiss Cheese Like Landscape on Mars
27.03.2001

Why do parts of the south pole of Mars look like swiss cheese? This little-understood landscape features flat-topped mesas nearly 4 meters high and circular indentations over 100 meters across. Since this swiss-cheese topography...

APOD: 2025 July 6 Б The Spiral North Pole of Mars
6.07.2025

Why is there a spiral around the North Pole of Mars? Each winter this pole develops a new outer layer about one meter thick composed of carbon dioxide frozen out of the thin Martian atmosphere. This fresh layer is deposited on a water-ice layer that exists year round.

Layers of the South Pole of Mars
31.07.2018

What lies beneath the layered south pole of Mars? A recent measurement with ground-penetrating radar from ESA's Mars Express satellite has detected a bright reflection layer consistent with an underground lake of salty water. The reflection comes from about 1.5-km down but covers an area 200-km across.