M32: Blue Stars in an Elliptical Galaxy
3.11.1999

Elliptical galaxies are known for their old, red stars. But is this old elliptical up to new tricks? In recent years, the centers of elliptical galaxies have been found to emit unexpectedly high amounts of blue and ultraviolet light.

Volcanic Terrain on Mercury
27.05.2009

Why are many large craters on Mercury relatively smooth inside? Recent images from the robotic MESSENGER spacecraft that flew by Mercury last October show previously uncharted regions of Mercury that have large craters with an internal smoothness similar to the maria on Earth's own Moon.

NGC 6240: Merging Galaxies
18.06.2009

NGC 6240 offers a rare glimpse of a cosmic catastrophe in its final throes. The titanic galaxy-galaxy collision is located a mere 400 million light-years away in the constellation Ophiuchus. One of the brightest...

Planetary Nebula Mz3: The Ant Nebula
25.04.2010

Why isn't this ant a big sphere? Planetary nebula Mz3 is being cast off by a star similar to our Sun that is, surely, round. Why then would the gas that is streaming away create an ant-shaped nebula that is distinctly not round?

Comet Hartley 2 Flyby
5.11.2010

Follow these 5 frames clockwise starting from the top left to track the view from the EPOXI mission spacecraft as it approached, passed under, and then looked back at the nucleus of comet Hartley 2 on November 4. Its closest approach distance was about 700 kilometers.

Huge Gamma Ray Bubbles Found Around Milky Way
10.11.2010

Did you know that our Milky Way Galaxy has huge bubbles emitting gamma rays from the direction of the galactic center? Neither did anybody. As the data from the Earth-orbiting Fermi satellite began acuminating over the past two years, however, a large and unusual feature toward our Galaxy's center became increasingly evident.

Saturns Hexagon Comes to Light
22.01.2012

Believe it or not, this is the North Pole of Saturn. It is unclear how an unusual hexagonal cloud system that surrounds Saturn's north pole was created, keeps its shape, or how long it will last.

A Hole in Mars
18.07.2012

What created this unusual hole in Mars? The hole was discovered by chance on images of the dusty slopes of Mars' Pavonis Mons volcano taken by the HiRISE instrument aboard the robotic Mars Reconnaissance Orbiter currently circling Mars. The hole appears to be an opening to an underground cavern, partly illuminated on the image right.

Plutos Newly Discovered Moons Receive Names
8.07.2013

Pluto's newly discovered moons now have names. Known previously as P4 and P5, the International Astronomical Union has now given the fourth and fifth discovered moons of Pluto the names Kerberos and Styx.

Wolf Rayet Star 124: Stellar Wind Machine
1.07.2014

Some stars explode in slow motion. Rare, massive Wolf-Rayet stars are so tumultuous and hot that they slowly disintegrating right before our telescopes. Glowing gas globs each typically over 30 times more massive than the Earth are being expelled by violent stellar winds.