APOD: 2025 June 3 Б Rainbow Airglow over the Azores
3.06.2025

Why would the sky glow like a giant repeating rainbow? Airglow. Now, air glows all of the time, but it is usually hard to see. A disturbance however -- like an approaching storm -- may cause noticeable rippling in the Earth's atmosphere.

Spiral Galaxy NGC 4038 in Collision
12.08.2012

This galaxy is having a bad millennium. In fact, the past 100 million years haven't been so good, and probably the next billion or so will be quite tumultuous. Visible on the upper...

The Colliding Galaxies of NGC 520
12.09.2005

Is this one galaxy or two? The jumble of stars, gas, and dust that is NGC 520 is now thought to incorporate the remains of two separate galaxies. A combination of observations and simulations indicate the NGC 520 is actually the collision of two disk galaxies.

Across the Universe
28.03.2008

How far can you see? Even the faintest stars visible to the eye are merely hundreds or thousands of light-years distant, all well within our own Milky Way Galaxy. Of course, if you know where to look you can also spot the Andromeda Galaxy as a pale, fuzzy cloud, around 2.5 million light-years away.

Voorwerpjes in Space
4.04.2015

Mysterious Hanny's Voorwerp, Dutch for "Hanny's Object", is really enormous, about the size of the Milky Way Galaxy and glowing strongly in the greenish light produced by ionized oxygen atoms.

Two Hemisphere Night Sky
27.02.2020

The Sun is hidden by a horizon that runs across the middle in this two hemisphere view of Earth's night sky. The digitally stitched mosaics were recorded from corresponding latitudes, one 29 degrees north and one 29 degrees south of the planet's equator.

A Dark Sky Over Sequoia National Park
27.08.2009

Scroll right to take in the view from the highest summit in the contiguous USA. The above 360-degree digitally stitched panorama, taken in mid-July, shows the view from 4,400-meter high Mt. Whitney in Sequoia National Park, California. In the foreground, angular boulders populate Mt.

Simulation: A Disk Galaxy Forms
17.07.2012

How do galaxies like our Milky Way form? Since our universe moves too slowly to watch, faster-moving computer simulations are created to help find out. Green depicts (mostly) hydrogen gas in the above movie, while time is shown in billions of years since the Big Bang on the lower right.