Mapping Mars
19.03.1999

This month, the Mars Global Surveyor (MGS) spacecraft began its primary mission to the red planet. Orbiting about once every two hours at an altitude of over 200 miles, instruments onboard MGS now regularly explore the Martian surface and atmosphere.

Night Shining Clouds
5.07.2007

Alluring noctilucent or night-shining clouds lie near the edge of space, some 80 kilometers above Earth's surface. Of course, when viewed from space the clouds are more properly called polar mesospheric clouds (PMCs) -- seen here for the first time in image data from the Aeronomy of Ice in the Mesosphere (AIM) satellite.

APOD: 2025 September 7 Б All the Water on Planet Earth
7.09.2025

How much of planet Earth is made of water? Very little, actually. Although oceans of water cover about 70 percent of Earth's surface, these oceans are shallow compared to the Earth's radius.

The Coldest Place on Earth
11.12.2013

How cold can it get on Earth? In the interior of the Antarctica, a record low temperature of -93.2 C (-135.8 F) has been recorded. This is about 25 C (45 F) colder than the coldest lows noted for any place humans live permanently.

Comet Hale-Bopp Over Val Parola Pass
17.03.1997

Comet Hale-Bopp is now much brighter than any surrounding stars. It can be seen even over bright city lights. Out away from city lights, however, it is putting on quite a spectacular show. Here Comet Hale-Bopp was photographed last week above Val Parola Pass in the Dolomite mountains surrounding Cortina d'Ampezzo, Italy.

Collapse in Hebes Chasma on Mars
28.05.2017

What's happened in Hebes Chasma on Mars? Hebes Chasma is a depression just north of the enormous Valles Marineris canyon. Since the depression is unconnected to other surface features, it is unclear where the internal material went.

The Missing Craters of Asteroid Itokawa
9.02.2014

Where are the craters on asteroid Itokawa? Missing -- unexpectedly. The Japanese robot probe Hayabusa approached the Earth-crossing asteroid in 2005 and returned pictures showing a surface unlike any other Solar System body yet photographed -- a surface possibly devoid of craters.

Moondog Night
10.12.2014

In this night scene from the early hours of November 14, light from a last quarter Moon illuminates clouds above the mountaintop domes of Kitt Peak National Observatory near Tucson, Arizona. Bright Jupiter...

Unusual Pits Discovered on Pluto
25.11.2015

Why are there unusual pits on Pluto? The indentations were discovered during the New Horizons spacecraft's flyby of the dwarf planet in July. The largest pits span a kilometer across and dip tens...

Mars from Earth
18.07.2001

Last month, Mars and Earth were right next to each other in their orbits. Formally called opposition, the event was highlighted by a very bright Mars for skywatchers and a good photo opportunity for the Hubble Space Telescope. Above, Hubble snapped the highest resolution picture of Mars ever obtained from the Earth.