APOD: 2024 January 3 Б A SAR Arc from New Zealand
3.01.2024

What is that unusual red halo surrounding this aurora? It is a Stable Auroral Red (SAR) arc. SAR arcs are rare and have only been acknowledged and studied since 1954. The featured wide-angle photograph...

HUDF: Dawn of the Galaxies
29.09.2004

When did galaxies form? Faint red smudges identified on the deepest optical sky image ever taken may well be members of the first class of galaxies. Detailed inspection of the Hubble Ultra Deep Field...

Distant Galaxies in Radio Vision
8.02.2001

Radio waves, like visible light, are electromagnetic radiation and radio telescopes can "see" -- their signals translated into radio images of the cosmos. While individually even the largest radio telescopes have very blurry vision compared to their optical counterparts, networks of radio telescopes can combine signals to produce sharper pictures.

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.

Simulated Galaxy Cluster View
6.03.2002

Stunningly detailed, this picture is a computer simulated view of a cluster of galaxies in the distant cosmos. A large, elliptical galaxy dominates this hypothetical cluster's central region surrounded by a swarm of member galaxies.

Seven Sisters versus California
5.04.2022

On the upper right, dressed in blue, is the Pleiades. Also known as the Seven Sisters and M45, the Pleiades is one of the brightest and most easily visible open clusters on the sky. The Pleiades contains over 3,000 stars, is about 400 light years away, and only 13 light years across.

APOD: 2025 March 5 Б Seven Sisters versus California
5.03.2025

On the right, dressed in blue, is the Pleiades. Also known as the Seven Sisters and M45, the Pleiades is one of the brightest and most easily visible open clusters on the sky. The Pleiades contains over 3,000 stars, is about 400 light years away, and only 13 light years across.

NGC 6334: The Cats Paw Nebula
13.09.2017

Nebulas are perhaps as famous for being identified with familiar shapes as perhaps cats are for getting into trouble. Still, no known cat could have created the vast Cat's Paw Nebula visible in Scorpius.

NGC 6334: The Cats Paw Nebula
18.06.2014

Nebulas are perhaps as famous for being identified with familiar shapes as perhaps cats are for getting into trouble. Still, no known cat could have created the vast Cat's Paw Nebula visible in Scorpius.

A Proton Aurora
17.12.2003

What are auroras made out of? Most auroras are caused by the solar wind exciting electrons that are funneled down the Earth's magnetic field. These electrons strike air molecules, liberating other electrons that glow when re-acquired.