A Double Ringed Basin on Mercury
7.10.2009

What created the internal second ring of this double ringed basin on Mercury? No one is sure. The unusual feature spans 160 kilometers and was imaged during the robotic MESSENGER spacecraft's swing past our Solar System's innermost planet last week.

Saturn in Blue and Gold
29.08.2017

Why is Saturn partly blue? The featured picture of Saturn approximates what a human would see if hovering close to the giant ringed world. The image was taken in 2006 March by the robot Cassini spacecraft now orbiting Saturn. Here Saturn's majestic rings appear directly only as a thin vertical line.

Perseverance: Seven Minutes to Mars
16.02.2021

How hard is it to land safely on Mars? So hard that many more attempts have failed than succeeded. The next attempt will be on Thursday. The main problem is that the Martian atmosphere is too thick to ignore -- or it will melt your spacecraft.

APOD: 2025 May 4 Б Spin up of a Supermassive Black Hole
4.05.2025

How fast can a black hole spin? If any object made of regular matter spins too fast -- it breaks apart. But a black hole might not be able to break apart -- and its maximum spin rate is really unknown.

X Ray Stars and Winds in the Rosette Nebula
19.10.2001

This mosaic of x-ray images cuts a swath across the photogenic Rosette Nebula, a stellar nursery 5,000 light-years from Earth in the constellation Monoceros, the Unicorn. Constructed from data recorded by the orbiting...

Sungrazer
26.02.1997

Arcing toward a fiery fate, this Sungrazer comet was recorded by the SOHO spacecraft's Large Angle Spectrometric COronagraph (LASCO) on Dec. 23rd, 1996. LASCO uses an occulting disk, partially visible at the lower...

X Rays From Tycho s Supernova Remnant
22.05.2004

In 1572, Danish astronomer Tycho Brahe recorded the sudden appearance of a bright new star in the constellation Cassiopeia. The new star faded from view over a period of months and is believed to have been a supernova, one of the last stellar explosions seen in our Milky Way galaxy.

Molecular Torus Surrounds Black Hole
8.09.2004

Why do some black hole surroundings appear brighter than others? In the centers of active galaxies, supermassive black holes at least thousands of times the mass of our Sun dominate. Many, called Seyfert Type I, are very bright in visible light. Others, called Seyfert Type II, are rather dim.

Gamma Ray Earth
31.03.2005

The pixelated planet above is actually our own planet Earth seen in gamma rays - the most energetic form of light. In fact, the gamma rays used to construct this view pack over 35 million electron volts (MeV) compared to a mere two electron volts (eV) for a typical visible light photon.

Short Gamma Ray Bursts Localized
17.10.2005

What causes gamma-ray bursts? The most energetic type of explosions known in the cosmos has been an enigma since discovered over 30 years ago. It now appears that there may not be one unique type of progenitor.