APOD: 2011 December 12 An Unusual Vein of Deposited Rock on Mars
12.12.2011

What could create this unusual vein of rock on Mars? A leading hypothesis is that this thin rock layer dubbed "Homestake" was deposited by a running liquid -- like most mineral veins are here on Earth. And the running liquid of choice is water.

Unusual Hollows Discovered on Planet Mercury
27.03.2012

What are those unusual features on planet Mercury? The slightly bluish tinge of features dubbed hollows has been exaggerated on the above image by the robotic MESSENGER spacecraft currently orbiting Mercury. The rounded depressions...

Terminator Moon
15.02.2022

What's different about this Moon? It's the terminators. In the featured image, you can't directly see any terminator -- the line that divides the light of day from the dark of night. That's because the image is a digital composite of 29 near-terminator lunar strips.

APOD: 2023 April 30 Б Saturns Moon Helene in Color
30.04.2023

Although its colors may be subtle, Saturn's moon Helene is an enigma in any light. The moon was imaged in unprecedented detail in 2012 as the robotic Cassini spacecraft orbiting Saturn swooped to within a single Earth diameter of the diminutive moon.

APOD: 2005 December 28- Smooth Sections on Asteroid Itokawa
28.12.2005

What are parts of this asteroid's surface so smooth? No one is yet sure, but it may have to do with the dynamics of an asteroid that is a loose pile of rubble rather than a solid rock.

Eclipsed Moon and Stars
8.03.2007

This dramatic image features a dark red Moon during a total lunar eclipse -- celestial shadow play enjoyed by many denizens of planet Earth last Saturday. Recorded near Wildon, Austria, the picture is a composite...

A Crumbling Layered Butte on Mars
5.10.2016

What is this unusual mound on Mars? NASA's Curiosity rover rolling across Mars has come across a group of these mounds that NASA has labelled Murray Buttes. Pictured is a recently assembled mosaic image of one of the last of the buttes passed by Curiosity on its way up Mt.

Aeolian Mars
2.02.2000

Mars' atmosphere is relatively thin, still when martian winds blow they weather and shape its surface. Like familiar aeolian features on Earth, this field of dunes within Mars' Rabe crater exhibits graceful undulating ridges which can shift as windblown material is deposited on the dunes' windward face and falls away down the steeper leeward slopes.

700 Kilometers Below Comet Hartley 2
8.11.2010

What kind of comet is this? Last week, NASA's robotic EPOXI spacecraft whizzed past Comet 103P/Hartley, also known as Comet Hartley 2, and recorded images and data that are both strange and fascinating. EPOXI was near its closest approach -- about 700 kilometers away -- when it snapped the above picture.

Earths Richat Structure
19.05.2013

What on Earth is that? The Richat Structure in the Sahara Desert of Mauritania is easily visible from space because it is nearly 50 kilometers across. Once thought to be an impact crater, the Richat Structure's flat middle and lack of shock-altered rock indicates otherwise.