APOD: 2026 March 10 Б Sky Glows over Paranal Observatory
10.03.2026

Are lasers from giant telescopes being used to defend the Earth? No. Lasers shot from telescopes are now commonly used to help increase the accuracy of astronomical observations. In some directions, Earth atmosphere-induced fluctuations in starlight can indicate how the air mass over a telescope is changing, but in other directions, no bright star exists.

HUDF Infrared: Dawn of the Galaxies
9.12.2009

When did galaxies form? To help find out, the deepest near-infrared image of the sky ever has been taken of the same field as the optical-light Hubble Ultra Deep Field (HUDF) in 2004. The new image was taken this summer by the newly installed Wide Field Camera 3 on the refurbished Hubble Space Telescope.

Earendel: A Star in the Early Universe
6.04.2022

Is Earendel the farthest star yet discovered? This scientific possibility started when the Hubble Space Telescope observed a huge cluster of galaxies. The gravitational lens effectбof this cluster was seen to magnify and distort a galaxy far in the background.

A Redshift Lookup Table for our Universe
8.04.2013

How far away is "redshift six"? Although humans are inherently familiar with distance and time, what is actually measured for astronomical objects is redshift, a color displacement that depends on exactly how energy density has evolved in our universe.

Hot Gas and Dark Matter
2.09.1995

Is the gravity of the above galaxies high enough to contain the glowing hot gas? Superposed on an optical picture of a group of galaxies is an image taken in X-ray light. The X-ray...

The Galactic Ring of NGC 6782
21.11.2001

Do spiral galaxies look the same in every color? NGC 6782 demonstrates colorfully that they do not. In visible light, NGC 6782 appears to be a normal spiral galaxy with a bright bar across its center.

M74: A Grand Design Spiral Galaxy
9.07.1996

M74 is about the same size as our own Milky Way Galaxy. Like our Milky Way, M74 is classified a spiral galaxy. M74's sweeping lanes of stars and dust combined with its small nucleus make it a classic Grand Design Spiral. On the Hubble Sequence of Galaxies, M74 is listed as "Sc".

Behind Betelgeuse
11.05.2020

What's behind Betelgeuse? One of the brighter and more unusual stars in the sky, the red supergiant star Betelgeuse can be found in the direction of famous constellation Orion. Betelgeuse, however, is actually...

Arp 273: Battling Galaxies from Hubble
20.11.2019

What's happening to these spiral galaxies? Although details remain uncertain, there sure seems to be a titanic battle going on. The upper galaxy is labelled UGC 1810 by itself, but together with its collisional partners is known as Arp 273.

The Colors and Mysteries of Centaurus A
12.08.2002

Why is spiral galaxy Centaurus A in so much turmoil? The above composite image shows different clues to the unusual galaxy's past in different bands of light. In low energy radio waves, shown in red, lobes across the thick swath of dust glow brightly.