The Lunar X
28.02.2018

The striking X in this lunarscape is easily visible in binoculars or a small telescope, but not too many have seen it. The catch is, this lunar X is fleeting and only apparent in the hours before the Moon's first quarter phase.

Animation: Spiral Disk around a Black Hole
19.08.2019

What would it look like to orbit a black hole? Many black holes are surrounded by swirling pools of gas known as accretion disks. These disks can be extremely hot, and much of the orbiting gas will eventually fall through the black hole's event horizon -- where it will never been seen again.

Apollo 12: Self Portrait
23.11.2019

Is this image art? 50 years ago, Apollo 12 astronaut-photographer Charles "Pete" Conrad recorded this masterpiece while documenting colleague Alan Bean's lunar soil collection activities on Oceanus Procellarum. The featured image is dramatic and stark.

Video of a Green Flash
9.11.2021

Many think it is just a myth. Others think it is true but its cause isn't known. Adventurers pride themselves on having seen it. It's a green flash from the Sun. The truth is the green flash does exist and its cause is well understood.

Melas, Candor, and Ophir: Valleys of Mariner
16.02.2005

First imaged by the Mariner 9 spacecraft, Valles Marineris, the grand canyon of Mars, is a system of enormous depressions or chasmas that stretch some 4,000 kilometers along the Martian equator. Looking north over the canyon's central regions, dark Melas Chasma lies in the foreground of this spectacular perspective view.

Meteor in the Milky Way
22.04.2015

Earth's April showers include the Lyrid Meteor Shower, observed for more than 2,000 years when the planet makes its annual passage through the dust stream of long-period Comet Thatcher. A grain...

Little Planet to Exoplanets
13.09.2019

Of course this little planet is really planet Earth in a digitally stitched 360 x 180 degree mosaic captured high in the Chilean Atacama desert. The seemingly large domes house the 1-meter diameter telescopes of the SPECULOOS Southern Observatory.

Comet Leonard Before Star Cluster M3
11.12.2021

Comet Leonard is now visible to the unaided eye -- but just barely. Passing nearest to the Earth today, the comet is best seen this week soon after sunset, toward the west, low on the horizon.

Anticrepuscular Rays Over Colorado
29.10.2001

What's happening over the horizon? Although the scene may appear somehow supernatural, nothing more unusual is occurring than a setting Sun and some well placed clouds. Pictured above are anticrepuscular rays. To understand them, start by picturing common crepuscular rays that are seen any time that sunlight pours though scattered clouds.

Comet McNaught Heads for the Sun
4.01.2007

Early morning risers with a clear and unobstructed eastern horizon can enjoy the sight of Comet McNaught (C/2006 P1) in dawn skies over the next few days. Discovered in August by R. H. McNaught...