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.

1999 Leonid Fireball
2.12.1999

Most Leonid meteoroids, the bits of comet debris which produce the annual Leonid meteor shower, range from a mere millimeter to a centimeter in diameter. Yet these cosmic grains of sand and gravel can put on quite a spectacular show. How can something so small generate so much light?

Spirit Rover at Engineering Flats on Mars
7.03.2010

Is it art? If so, the paintbrush was the Spirit robotic rover, the canvas was the soil on Mars, and the artists were the scientists and engineers of the Mars Exploration Rover Mission. This...

Crescent Moon and Planets Over Portugal
18.08.2010

Sometimes, it's fun to share the sky. Although it might appear that the two sky enthusiasts on the ridge are sharing only a crescent moon between them, three bright planets also stand before them.

Moon, Planets, and Rocket Trails
14.07.1999

Are you an early riser? Over the last month or so, the bright planets Jupiter and Saturn have come to adorn eastern skies before sunrise. In fact, astrophotographer Joe Orman anticipated that an early...

Layers in Aureum Chaos
4.04.2008

At first glance these undulating shapes in shades of blue might look like waves on an ocean. Seen here in a false-color image from the Mars Reconnaissance Orbiter's HiRISE camera, they are actually layered rock outcrops found in Aureum Chaos.

The Early Universe
16.02.1996

What did our universe look like when it was young? To answer this, cosmologists run sophisticated computer programs tracking the locations of millions of particles. The above animated frame is the result of such a calculation and shows how our universe might have looked when it was just a fracton of its current age.

The Road to Victoria Crater on Mars
5.06.2006

Here is a road never traveled. To get to Victoria Crater on Mars, the rolling robotic rover Opportunity must traverse the landscape shown above. Victoria Crater lies about one kilometer ahead. The intervening terrain shows a series of light rock outcrops that appears like some sort of cobblestone road.

Meteor before Galaxy
12.08.2018

What's that green streak in front of the Andromeda galaxy? A meteor. While photographing the Andromeda galaxy in 2016, near the peak of the Perseid Meteor Shower, a sand-sized rock from deep space crossed right in front of our Milky Way Galaxy's far-distant companion.

Leonids from Leo
17.11.2002

Is Leo leaking? Leo, the famous sky constellation visible on the left of the above all-sky photograph, appears to be the source of all the meteors seen in last year's Leonids Meteor Shower.