Light Echoes from V838 Mon
27.03.2003

Nominated for most mysterious star in the Milky Way, V838 Monocerotis briefly became one of the brightest stars in our galaxy. Its outburst discovered in January 2002, observations have indicated that V838 Mon somehow...

Phobos: Doomed Moon of Mars
6.04.2003

This moon is doomed. Mars, the red planet named for the Roman god of war, has two tiny moons, Phobos and Deimos, whose names are derived from the Greek for Fear and Panic. These...

A Gemini Sky
9.09.2003

Where will Gemini take us tonight? It is dusk and Gemini North, one of the largest telescopes on planet Earth, prepares to peer into the distant universe. Gemini's flexible 8.1-mirror has taken...

4500 Kilometers Above Dione
26.10.2005

What does the surface of Saturn's moon Dione look like? To find out, the robot Cassini spacecraft currently orbiting Saturn flew right past the fourth largest moon of the giant planet earlier this month. Pictured above is an image taken about 4,500 kilometers above Dione's icy surface, spanning about 23 kilometers.

SN 1006 Supernova Remnant
12.07.2014

A new star, likely the brightest supernova in recorded human history, lit up planet Earth's sky in the year 1006 AD. The expanding debris cloud from the stellar explosion, found in the southerly constellation of Lupus, still puts on a cosmic light show across the electromagnetic spectrum.

The Butterfly Nebula from Hubble
1.10.2014

The bright clusters and nebulae of planet Earth's night sky are often named for flowers or insects. Though its wingspan covers over 3 light-years, NGC 6302 is no exception. With an estimated surface...

Earthset from Orion
20.11.2024

Eight billion people are about to disappear in this snapshot from space taken on 2022 November 21. On the sixth day of the Artemis I mission, their home world is setting behind the Moon's bright edge as viewed by an external camera on the outbound Orion spacecraft.

Moon Pi and Mountain Shadow
14.03.2025

What phase of the Moon is 3.14 radians from the Sun? The Full Moon, of course. Even though the Moon might look full for several days, the Moon is truly at its full phase when it is Pi radians (aka 180 degrees) from the Sun in ecliptic longitude.

Jupiter Eyes Ganymede
12.12.2000

Who keeps an eye on the largest moon in the Solar System? This moon, visible on the lower right, is Ganymede, and the planet it orbits, Jupiter, seems to be keeping a watchful eye, as its Great Red Spot appears serendipitously nearby.

Venusian Half Shell
11.12.2001

Venus, second planet from the Sun, appears above imaged for the first time ever in x-rays (left) by the orbiting Chandra Observatory. Chandra's smoothed, false-color, x-ray view is compared to an optical image (right) from a small earthbound telescope.