In Green Company: Aurora over Norway
9.12.2017

Raise your arms if you see an aurora. With those instructions, two nights went by with, well, clouds -- mostly. On the third night of returning to same peaks, though, the sky not only cleared up but lit up with a spectacular auroral display.

Mercury in Silhouette
12.11.2019

The small, dark, round spot in this solar close up is planet Mercury. In the high resolution telescopic image, a colorized stack of 61 sharp video frames, a turbulent array of photospheric convection cells tile the bright solar surface. Mercury's more regular silhouette still stands out though.

Ice Volcanoes on Mars
29.06.2001

What causes these unusual cone-shaped features on Mars? Spanning an average of only 100 meters at the base, these small cones appear near massive Martian volcanoes such as Olympus Mons. Near the cones are also dry channels and eroded banks.

Tail Wags of Comet Ikeya Zhang
15.05.2002

As Comet Ikeya-Zhang approached the Sun two months ago, it developed a complex blue ion tail. The tail was composed of ions that boiled off the nucleus and were pushed away from the Sun by the out-flowing fast-moving particles of the solar wind.

Venus and the Chromosphere
11.06.2004

Enjoying the 2004 Transit of Venus from Stuttgart, Germany, astronomer Stefan Seip recorded this fascinating, detailed image of the Sun. Revealing a network of cells and dark filaments against a bright solar disk with spicules and prominences along the Sun's limb, his telescopic picture was taken through an H-alpha filter.

Transit of Venus Stereogram
17.07.2004

Venus glides in front of an enormous solar disk in these two frames from the TRACE satellite imaging of the inner planet's 2004 transit. Arranged in a "right/left" stereogram, the frames are intended...

ISS and Discovery Transit the Sun
29.07.2005

That large sunspot near the right edge of the Sun is actually not a sunspot at all. It's the International Space Station (ISS) docked with the Space Shuttle Discovery on mission STS-114.

Sunrise by Season
20.12.2005

Does the Sun always rise in the same direction? No. As the seasons change, the direction toward the rising Sun will change, too. The Sun will always rise and set furthest to the south during the day of Winter Solstice, and furthest to the north during Summer Solstice.

Neptune through Adaptive Optics
17.02.2000

From the Earth's surface, Neptune usually appears as a fuzzy blotch. The blurring effects of the Earth's atmosphere deny clearer images. By distorting mirrors in the telescope itself in time with the changing atmosphere, however, these effects can be greatly reduced.

Verona Rupes: Tallest Known Cliff in the Solar System
23.07.2007

Could you survive a jump off the tallest cliff in the Solar System? Quite possibly. Verona Rupes on Uranus' moon Miranda is estimated to be 20 kilometers deep -- ten times the depth of the Earth's Grand Canyon.