Mosaic of Endurance Crater on Mars
11.10.2004

Where should this Martian rover explore next? Possible choices for the Opportunity rover team on Earth in early August were to send the Martian robot inside Endurance crater toward the arc-shaped sand dunes...

MyCn18: An Hourglass Planetary Nebula
7.08.2011

The sands of time are running out for the central star of this hourglass-shaped planetary nebula. With its nuclear fuel exhausted, this brief, spectacular, closing phase of a Sun-like star's life occurs as its outer layers are ejected - its core becoming a cooling, fading white dwarf.

A Twisted Meteor Train
2.02.2005

Did this meteor leave a twisting path? Evidently. Meteor trains that twist noticeably are rare - and even more rarely photographed - but have been noted before. The underlying reason for unusual meteors trains is that many meteors are markedly non-spherical in shape and non-uniform in composition.

A Leonids Meteor Storm in 1999
24.11.1999

The 1999 Leonids meteor shower was not equally good for everybody. Only observers in Europe and the Middle East with clear skies near 2 am (UTC) on 1999 November 18 saw rates shoot up to a meteor every few seconds.

Geminid Meteors over Xinglong Observatory
13.12.2020

Where do Geminid meteors come from? In terms of location on the sky, as the featured image composite beautifully demonstrates, the sand-sized bits of rock that create the streaks of the Geminids meteor shower appear to flow out from the constellation of Gemini.

A Meteor Wind over Tunisia
16.08.2022

Does the Earth ever pass through a wind of meteors? Yes, and they are frequently visible as meteor showers. Almost all meteors are sand-sized debris that escaped from a Sun-orbiting comet or asteroid, debris that continues in an elongated orbit around the Sun.

A Martian Metamorphosis
4.06.2002

Is it an Escher, or Mars? Three different types of surfaces visible in the North Polar Cap of Mars morph into each other in a way perhaps reminiscent of the works of M. C. Escher. On the far left dark sand covers the ground, while the center shows a transition to a dune field.

Rolling Across the Rocky Plains of Mars
4.10.2010

You stare out across the rocky plains of Mars. Before you, in every direction, is dark sand and bright rock. Although little has changed here for millions of years, no one has ever seen this view before. You are being sent on a long journey to a distant crater, the largest crater in the region.

Geminid Meteors over Xinglong Observatory
23.12.2015

Where do Geminid meteors come from? In terms of location on the sky, as the featured image composite beautifully demonstrates, the sand-sized bits of rock that create the streaks of the Geminid Meteor Shower appear to flow out from the constellation of Gemini.

Steep Cliffs on Mars
1.07.2007

Vertical cliffs of nearly two kilometers occur near the North Pole of Mars. Also visible in the above image of the Martian North Polar Cap are red areas of rock and sand, white areas of ice, and dark areas of unknown composition but hypothesized to be volcanic ash.