Airglow Ripples over Tibet
20.11.2022

Why would the sky look like a giant target? Airglow. Following a giant thunderstorm over Bangladesh in late April, giant circular ripples of glowing air appeared over Tibet, China, as pictured here. The unusual...

White Dwarfs Cool
10.09.1995

The circled stars in the above picture are from a class that is hard to see in the cosmos: white dwarfs. The entire photo covers a small region near the center of a globular cluster known as M4. Researchers using the Hubble Space Telescope discovered a large concentration of white dwarfs in M4.

Crescent Neptune and Triton
18.06.2006

Gliding silently through the outer Solar System, the Voyager 2 spacecraft camera captured Neptune and Triton together in crescent phase in 1989. The above picture of the gas giant planet and its cloudy moon was taken from behind just after closest approach.

Shadow of a Martian Robot
8.05.2011

What if you saw your shadow on Mars and it wasn't human? Then you might be the Opportunity rover currently exploring Mars. Opportunity and sister robot Spirit have been probing the red planet since early 2004, finding evidence of ancient water, and sending breathtaking images across the inner Solar System.

Ash and Lightning Above an Icelandic Volcano
30.07.2012

Why did the picturesque 2010 volcanic eruption in Iceland create so much ash? Although the large ash plume was not unparalleled in its abundance, its location was particularly noticeable because it drifted across such well-populated areas.

Working in Space
29.05.2001

High above planet Earth, a human helps an ailing machine. The machine, in this potentially touching story, is the Hubble Space Telescope, which is not in the picture. The human is Astronaut Steven L.

Rays from an Unexpected Aurora
5.08.2002

This aurora was a bit of a surprise. For starters, last Friday morning, no intense auroral activity was expected at all. Possibly more surprising, however, the aurora appeared to show an usual structure of green rays from some locations.

A Gamma Ray Burst Supernova
8.05.1998

Did a gamma-ray burst precede this supernova? This intriguing suggestion came to light yesterday with the discovery of an evolving supernova that is potentially coincident with the position of gamma-ray burst GRB 980425, which occurred just two weeks ago. If true, this would tie together the two most violent phenomena known in the universe.

Mercury and Venus Over Paris
12.04.2010

Go outside tonight and see one of the more interesting planetary conjunctions of recent years. Just after sunset, the planets Mercury and Venus are visible quite near each other. Now Venus, being commonly discernible as one of the brightest objects in the sky, is frequently mistaken for an airplane.

Movie: Approaching Light Speed
18.10.2011

What would it look like to travel near the speed of light? Strange visual effects would appear as documented in the above relativistically-accurate animation. First of all, relativistic aberration would cause objects to appear to bunch up in front you.