Mercury Crosses a Quiet Sun
1.12.2019

What's that black dot crossing the Sun? The planet Mercury. Mercury usually passes over or under the Sun, as seen from Earth, but last month the Solar System's innermost planet appeared to go just about straight across the middle.

Winter and Summer on a Little Planet
29.11.2024

Winter and summer appear to come on a single night to this stunning little planet. It's planet Earth of course. The digitally mapped, nadir centered panorama covers 360x180 degrees and is composed of frames recorded during January and July from the Col du Galibier in the French Alps.

Happy 40th Birthday NASA
1.10.1998

Happy Birthday, NASA! The National Aeronautics and Space Administration officially began operations on October 1, 1958, absorbing its forerunner organization the National Advisory Committee for Aeronautics, NACA. Its landmark achievements in human spaceflight include...

Other Worlds and HD 38529
10.08.2000

After the latest round of discovery announcements, the list of known worlds of distant suns has grown to 50. While extrasolar planet discoveries are sure to continue, none - so far - points clearly to another planetary system like our own. Take, for example, the newly discovered parent star HD38529.

Man Enters Space
12.04.1996

Thirty five years ago today, Soviet cosmonaut Yuri Alexseyevich Gagarin became the first human in space. On April 12, 1961, his remotely controlled Vostok 1 spacecraft lofted him to an altitude of 200 miles and carried him once around planet Earth.

Julius Caesar and Leap Days
28.02.2016

Today, February 29th, is a leap day - a relatively rare occurrence. In 46 BC, Julius Caesar, featured here in a self-decreed minted coin, created a calendar system that added one leap day every four years.

APOD: 2023 July 4 Б Aurora over Icelandic Waterfall
3.07.2023

It seemed like the sky exploded. The original idea was to photograph an aurora over a waterfall. After waiting for hours under opaque clouds, though, hope was running out. Others left. Then, unexpectedly, the clouds moved away.

Green Aurora Over Lake Superior
6.09.2006

What if your horizon was green? If you've got a camera, take a picture! That was the experience of Jeff Hapeman last week when visiting the Pictured Rocks National Lakeshore in Michigan. On a quiet night toward the northern horizon over Lake Superior was a long lasting diffuse green aurora.

Star Trails in the North
23.12.2010

Pointing skyward, the wall of this ruined Viking church still stands after a thousand winters, near the town of Vallentuna, Sweden. The time exposure records the scene on December 14th as stars leave graceful arcing trails during a long night, reflecting planet Earth's daily rotation on its axis.

Lunar Orbiter Earthset
26.08.2016

August 10th was the 50th anniversary of the launch of Lunar Orbiter 1. It was the first of five Lunar Orbiters intended to photograph the Moon's surface to aid in the selection of future landing sites.