APOD Turns Eleven
16.06.2006

The first APOD appeared eleven years ago today, on 1995 June 16. Although garnering only 14 page views on that day, we are proud to estimate that APOD has now served over 400 million space-related images over the last eleven years.

Big Dipper over Pyramid Mountain
21.11.2017

When did you first learn to identify this group of stars? Although they are familiar to many people around the world, different cultures have associated this asterism with different icons and folklore. Known...

NGC 1569: Heavy Elements from a Small Galaxy
25.07.2002

For astronomers, elements other than hydrogen and helium are sometimes considered to be simply "heavy elements". It's understandable really, because even lumped all together heavy elements make up an exceedingly small fraction of the Universe. Still, heavy elements can profoundly influence galaxy and star formation ... not to mention the formation of planets and people.

A Milky Way Shadow at Loch Ard Gorge
23.08.2010

Have you ever seen the Milky Way's glow create shadows? To do so, conditions need to be just right. First and foremost, the sky must be relatively clear of clouds so that the long band of the Milky Way's central disk can be seen.

Elements in the Aftermath
26.10.2001

Massive stars spend their brief lives furiously burning nuclear fuel. Through fusion at extreme temperatures and densities surrounding the stellar core, nuclei of light elements like Hydrogen and Helium are combined to heavier elements like Carbon, Oxygen, etc. in a progression which ends with Iron.

Full Moon Silhouettes
3.12.2017

Have you ever watched the Moon rise? The slow rise of a nearly full moon over a clear horizon can be an impressive sight. One impressive moonrise was imaged in early 2013 over Mount Victoria Lookout in Wellington, New Zealand.

APOD: 2024 July 30 Б Arp 142: Interacting Galaxies from Webb
30.07.2024

To some, it looks like a penguin. But to people who study the universe, it is an interesting example of two big galaxies interacting. Just a few hundred million years ago, the upper NGC 2936 was likely a normal spiral galaxy: spinning, creating stars, and minding its own business.

APOD: 2023 December 10 Б Big Dipper over Pyramid Mountain
10.12.2023

When did you first learn to identify this group of stars? Although they are familiar to many people around the world, different cultures have associated this asterism with different icons and folklore. Known...

Pickerings Triangle from Kitt Peak
1.07.2008

Wisps like this are all that remain visible of a Milky Way star. About 7,500 years ago that star exploded in a supernova leaving the Veil Nebula, also known as the Cygnus Loop.

Zodiacal Light Over Namibia
13.09.2010

An unusual triangle of light is visible this time of year just before dawn, in the northern hemisphere. Once considered a false dawn, this triangle of light is actually zodiacal light, light reflected from interplanetary dust particles.