Mercury: A Cratered Inferno
12.09.2004

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.

The International Space Station from Above
2.03.2010

The International Space Station (ISS) is the largest human-made object ever to orbit the Earth. The ISS is so large that it can be seen drifting overhead with the unaided eye, and is frequently imaged from the ground in picturesque fashion.

Atlantis Last Approach
13.07.2011

For the last time, the US Space Shuttle has approached the International Space Station (ISS). Following a dramatic launch from Cape Canaveral last week that was witnessed by an estimated one million people, Space Shuttle Atlantis on STS-135 lifted a small crew to a welcome rendezvous three days ago with the orbiting station.

Jupiter Near Opposition
22.10.2011

On October 29 (UT), Jupiter, the solar system's largest planet, will be at opposition, opposite the Sun in planet Earth's sky, shining brightly and rising as the Sun sets. That configuration results...

Rigel and the Witch Head Nebula
1.11.2012

Double, double toil and trouble; Fire burn, and cauldron bubble -- maybe Macbeth should have consulted the Witch Head Nebula. The suggestively shaped reflection nebula is associated with the bright star Rigel in the constellation Orion.

Aurora over Maine
17.09.2014

It has been a good week for auroras. Earlier this month active sunspot region 2158 rotated into view and unleashed a series of flares and plasma ejections into the Solar System during its journey across the Sun's disk.

APOD: 2024 January 8 Б The Phases of Venus
7.01.2024

Venus goes through phases. Just like our Moon, Venus can appear as a full circular disk, a thin crescent, or anything in between. Venus, frequently the brightest object in the post-sunset or pre-sunrise sky, appears so small, however, that it usually requires binoculars or a small telescope to clearly see its current phase.

APOD: 2024 June 17 Б Ou4: The Giant Squid Nebula
16.06.2024

Squids on Earth aren't this big. This mysterious squid-like cosmic cloud spans nearly three full moons on planet Earth's sky. Discovered in 2011 by French astro-imager Nicolas Outters, the Squid Nebula's bipolar shape is distinguished here by the telltale blue emission from doubly ionized oxygen atoms.

A Large Tsunami Shock Wave on the Sun
12.12.2006

Tsunami's this large don't happen on Earth. One week ago, a large solar flare from an Earth-sized sunspot produced a tsunami-type shock wave that was spectacular even for the Sun. Pictured above...

Lulin and Saturn near Opposition
26.02.2009

Tracking through the constellation Leo on February 23rd, bright planet Saturn and Comet Lulin were both near opposition -- opposite the Sun in planet Earth's sky. They also passed within only 2 degrees of each other creating a dramatic celestial photo-op.