M31: The Andromeda Galaxy
9.09.2019

How far can you see? The most distant object easily visible to the unaided eye is M31, the great Andromeda Galaxy, over two million light-years away. Without a telescope, even this immense spiral galaxy appears as an unremarkable, faint, nebulous cloud in the constellation Andromeda.

APOD: 2026 March 18 Б Cygnus and the Solitary Tree
18.03.2026

A lone tree stands in a quiet meadow in Guadalajara, Spain, silhouetted against the Cygnus region rising above like flames in the night sky. This deep night skyscape is a composite of exposures that reveals a range of brightness and color human eyes can't quite see on their own.

3C294: Distant X Ray Galaxy Cluster
22.02.2001

Large clusters of galaxies are the most massive objects in the universe. Astronomers now realize that a hallmark of these cosmic behemoths are gas clouds with temperatures of tens of millions of degrees that pervade the clusters and radiate strongly in x-rays.

The X-Ray Sky
2.01.1996

What if you could see X-rays? If you could, the night sky would be a strange and unfamiliar place. X-rays are about 1,000 times more energetic than visible light photons and are produced in violent and high temperature astrophysical environments.

Dark Matter, X rays, and NGC 720
26.10.2002

Elliptical galaxy NGC 720 is enveloped in a cosmic cloud of x-ray emitting gas. Seen in this false color image from the Chandra X-ray Observatory, the extreme temperature of the gas - about 7 million...

WIRO at Jupiter
13.03.2003

Gazing out over the mountaintops from the Wyoming InfraRed Observatory (WIRO), astronomers recently recorded this bizarre looking image of the solar system's ruling planet, gas giant Jupiter. The false-color picture is a composite...

SN 2005ap: The Brightest Supernova Yet Found
16.10.2007

What could cause a bang this big? This supernova explosion was so inherently bright that it could be seen nearby 5 billion light years away (a redshift of 0.28) even with a small telescope.

Spokes Reappear on Saturns Rings
2.06.2009

What causes the mysterious spokes in Saturn's rings? Visible in the above image as light ghostlike impressions, spokes were first discovered by the Voyager spacecraft that buzzed by Saturn in the early 1980s. Their existence was unexpected.

Farther Along
6.05.2011

What is humanity's most distant spacecraft? Launched in 1977, Voyager 1 now holds that distinction at 17.5 billion kilometers from the Sun. That corresponds to 16 light-hours or 117 Astronomical Units (AU). This...

Arp 240: A Bridge between Spiral Galaxies from Hubble
28.11.2016

Why is there a bridge between these two spiral galaxies? Made of gas and stars, the bridge provides strong evidence that these two immense star systems have passed close to each other and experienced violent tides induced by mutual gravity.