The Not So Quiet Sun
6.08.2010

After a long solar minimum, the Sun is no longer so quiet. On August 1, this extreme ultraviolet snapshot of the Sun from the Solar Dynanimcs Observatory captured a complex burst of activity playing across the Sun's northern hemisphere.

Leaning Tower, Active Sun
1.04.2022

The natural filter of a hazy atmosphere offered this recognizable architecture and sunset view on March 27. Dark against the solar disk, large sunspots in solar active regions 2975 and 2976 are wedged between the Duomo of Pisa and its famous Leaning Tower.

APOD: 2023 August 23 Б The Meteor and the Galaxy
23.08.2023

It came from outer space. It -- in this case a sand-sized bit of a comet nucleus -- was likely ejected many years ago from Sun-orbiting Comet Swift-Tuttle, but then continued to orbit the Sun alone.

Northern Lights, West Virginia
12.10.2024

A gravel country lane gently winds through this colorful rural night skyscape. Captured from Monroe County in southern West Virginia on the evening of October 10, the starry sky above is a familiar sight. Shimmering curtains of aurora borealis or northern lights definitely do not make regular appearances here, though.

Unusual Layers on Saturns Moon Phoebe
14.06.2004

What caused the unusual light and dark layers on Saturn's moon Phoebe? The layers were discovered just Friday during the Cassini spacecraft flyby of the small moon. Such layering is particularly evident on the crater just above the image center, where alternating light and dark material makes this crater appear particularly structured.

Saturns Moon Tethys from Cassini
29.11.2004

Tethys is one of the larger and closer moons of Saturn. The Cassini spacecraft now orbiting Saturn passed near the frozen moon at the end of October, capturing the most detailed images since the Voyager spacecrafts in the early 1980s.

Northern Spring on Mars
25.03.2006

Astronomical spring came to planet Earth's northern hemisphere this week (and autumn to the south) with the equinox on March 20th. But on Mars, northern spring began on January 22nd. Still in northern...

The Crater Chain
15.07.1995

NASA's robot spaceprobe Voyager 1, took this closeup image of the surface of Jupiter's crater scarred moon Callisto in 1979. A mysterious chain of craters is seen to extend diagonally across the image (upper left to lower right). What could cause the craters to line up in such a regular fashion?

Saturns Iapetus: Moon with a Strange Surface
1.02.2005

What has happened to Saturn's moon Iapetus? A strange ridge crosses the moon near the equator, visible near the bottom of the above image, making Iapetus appear similar to the pit of a peach. Half of Iapetus is so dark that it can nearly disappear when viewed from Earth.

The First Explorer
6.02.1999

The first US spacecraft was Explorer 1. The cylindrical 30 pound satellite was launched (above) as the fourth stage of a Jupiter-C rocket (a modified US Army Redstone ballistic missile) and achieved orbit on January 31, 1958.