A Leonid Meteor Over Sweden
21.11.2006

This past weekend, small remnant bits of a distant comet lit up the skies over much of planet Earth. Incoming reports, however, have this year's Leonid meteor shower as less active than Leonid meteor showers a few years ago.

Mercury: A Cratered Inferno
19.08.2001

Mercury's surface looks similar to our Moon's. Each is heavily cratered and made of rock. Mercury's diameter is about 4800 km, while the Moon's is slightly less at about 3500 km (compared with about 12,700 km for the Earth). But Mercury is unique in many ways.

Painting with Solar Neutrons
25.10.1995

Solar flares are propelled high above the Sun's surface by powerful, twisted magnetic fields. The flares spew high energy atomic and subatomic particles into space. During an intense solar flare on June 15, 1991, a spray of solar neutrons was detected by the COMPTEL instrument onboard NASA's Compton Gamma Ray Observatory.

A Total Eclipse of the Sun
11.03.1998

On February 26th, it was dark during the day. This total solar eclipse was the last visible from the Americas for this millennium. A total solar eclipse is exciting partly because it is so short.

Analemma Over Ancient Nemea
21.06.2004

An anelemma is that figure-8 curve that you get when you mark the position of the Sun at the same time each day throughout planet Earth's year. Above, 44 separate exposures (plus...

The Analemma and the Temple of Olympian Zeus
23.12.2006

An analemma is that figure-8 curve you get when you mark the position of the Sun at the same time each day throughout planet Earth's year. Above, 47 separate exposures (plus one foreground...

Martian Analemma
30.12.2006

On planet Earth, an analemma is the figure-8 loop you get when you mark the position of the Sun at the same time each day throughout the year. But similarly marking the position...

Endeavour to Orbit
16.03.2008

Birds don't fly as high. Airplanes don't go as fast. The Statue of Liberty weighs less. No species other than human can even comprehend what is going on, nor could any human just a millennium ago. The launch of a rocket bound for space is an event that inspires awe and challenges description.

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.

APOD: 2026 June 27 Б Mars Marathon by Perseverance
27.06.2026

In this recent HiRISE view from the Mars Reconnaissance Orbiter, the little green dot indicated on the surface of the big Red Planet is the Perseverance Mars rover. Recorded on June 13, the car-sized...