Hubble Floats Free
25.05.2009

Why put observatories in space? Most telescopes are on the ground. On the ground, you can deploy a heavier telescope and fix it more easily. The trouble is that Earth-bound telescopes must look through the Earth's atmosphere.

The First Image of an Extra Solar Planet
10.05.2005

It's the faint red object, not the bright white one that might be a historic find. The white object is surely a brown dwarf star. Quite possibly, however, the red object is the first direct image of a planet beyond our Solar System.

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.

Retrograde Mars
11.05.2008

Why would Mars appear to move backwards? Most of the time, the apparent motion of Mars in Earth's sky is in one direction, slow but steady in front of the far distant stars. About every two years, however, the Earth passes Mars as they orbit around the Sun.

Active Regions, CMEs, and X Class Flares
8.06.2000

Space Weather forcasters are predicting major storm conditions over the next few days as the active Sun has produced at least three strong flares and a large coronal mass ejection (CME) since Tuesday, June 6th.

APOD: 2025 July 7 Б Interstellar Comet 3I ATLAS
7.07.2025

It came from outer space. An object from outside our Solar System is now passing through at high speed. Classified as a comet because of its gaseous coma, 3I/ATLAS is only the third identified macroscopic object as being so alien.

Aerogel For Stardust
18.02.1999

On February 7th, this honey comb of aluminum cells filled with aerogel was launched on the STARDUST mission to interplanetary space. STARDUST's goal is to capture dust from a comet's tail and return to planet Earth - the first sample return mission to a comet!

APOD: 2023 October 1 Б A Desert Eclipse
1.10.2023

A good place to see a ring-of-fire eclipse, it seemed, would be from a desert. In a desert, there should be relatively few obscuring clouds and trees. Therefore late December of 2019, a group...

Bright Spiral Galaxy M81 in Ultraviolet from Galex
15.05.2007

Where are the hot stars in M81, one of the closest major spiral galaxies? To help find out, astronomers took a deep image in ultraviolet light of the sprawling spiral with the Earth-orbiting Galex telescope.

Retrograde Mars
27.10.2014

Why would Mars appear to move backwards? Most of the time, the apparent motion of Mars in Earth's sky is in one direction, slow but steady in front of the far distant stars. About every two years, however, the Earth passes Mars as they orbit around the Sun.