Atete Corona on Venus
12.03.2002

What could cause a huge cylindrical mountain to rise from the surface of Venus? Such features that occur on Venus are known as coronas. Pictured above in the foreground is 500-kilometer wide Atete Corona found in a region of Venus known as the Galindo.

Barnards Loop around the Horsehead Nebula
17.04.2006

Why is the Horsehead Nebula surrounded by a bubble? Although glowing like an emission nebula, the origin of the bubble, known as Barnard's Loop, is currently unknown. Progenitor hypotheses include the winds from bright Orion stars and the supernovas of stars long gone.

Saturn's Cloud Tops
17.03.1996

This close-up of the tops of Saturn's clouds was taken by the Voyager 1 robot spacecraft as it passed the giant planet in November 1980. Saturn's clouds are mostly composed of hydrogen and helium gas, but the small addition of other elements gives the clouds their colors.

White Rock Fingers on Mars
30.10.2011

What caused this unusual light rock formation on Mars? Intrigued by the possibility that they could be lakebed dried-up, detailed studies of these fingers now indicate a more mundane possibility: volcanic ash. Studying the exact color of the formation indicated the possible volcanic origin.

Shadow at the Lunar South Pole
28.11.1995

In 1994, the space probe Clementine spent 70 days in lunar orbit mapping the Moon's surface. Shown above is a dramatically detailed composite view centered on the Moon's South Pole constructed from 1500 Clementine images.

Valles Marineris: The Grand Canyon of Mars
24.08.2003

The largest canyon in the Solar System cuts a wide swath across the face of Mars. Named Valles Marineris, the grand valley extends over 3,000 kilometers long, spans as much as 600 kilometers across, and delves as much as 8 kilometers deep.

APOD: 2023 April 3 Б The Galactic Center Radio Arc
3.04.2023

What causes this unusual curving structure near the center of our Galaxy? The long parallel rays slanting across the top of the featured radio image are known collectively as the Galactic Center Radio Arc and point out from the Galactic plane.

Jupiters Moons Thebe, Amalthea, and Metis
8.05.2000

The robot spacecraft Galileo in orbit around Jupiter has recently photographed the inner moons of Jupiter in greater detail than ever before. These pictures of Thebe, Amalthea, and Metis are shown to scale, and reveal details as small as three kilometers across. Amalthea, by contrast, has a total length of about 200 kilometers.

APOD: 2024 November 10 Б Valles Marineris: The Grand Canyon of Mars
10.11.2024

The largest canyon in the Solar System cuts a wide swath across the face of Mars. Named Valles Marineris, the grand valley extends over 3,000 kilometers long, spans as much as 600 kilometers across, and delves as much as 8 kilometers deep.

Cracks and Ridges on Europa
2.06.2002

Which way to the interstate? What appears to be a caricature of a complex highway system on Earth is actually a system of ridges and cracks on the icy surface of Jupiter's moon Europa. The distance between parallel ridges in the above photograph is typically about 1 kilometer.