The Milky Way Over the Arizona Toadstools
22.02.2015

Which is older -- the rocks you see on the ground or the light you see from the sky? Usually its the rocks that are older, with their origin sentiments deposited well before light left any of the stars or nebulas you see in the sky.

SpaceX Rocket Launch Plume over California
24.12.2017

What's happened to the sky? On Friday, the photogenic launch plume from a SpaceX rocket launch created quite a spectacle over parts of southern California and Arizona. Looking at times like a giant...

The Extraordinary Spiral in LL Pegasi
8.07.2018

What created the strange spiral structure on the upper left? No one is sure, although it is likely related to a star in a binary star system entering the planetary nebula phase, when its outer atmosphere is ejected.

Lightning over Colorado
27.09.2020

Have you ever watched a lightning storm in awe? Join the crowd. Oddly, details about how lightning is produced remains a topic of research. What is known is that updrafts carry light ice crystals into collisions with larger and softer ice balls, causing the smaller crystals to become positively charged.

APOD: 2025 March 30 Б A Partial Solar Eclipse over Iceland
30.03.2025

What if the Sun and Moon rose together? That happened yesterday over some northern parts of planet Earth as a partial solar eclipse occurred shortly after sunrise. Regions that experienced the Moon blocking part of the Sun included northeastern parts of North America and northwestern parts of Europe, Asia, and Africa.

High Redshift Quasars
11.12.1998

Each red speck indicated above is a powerful quasar estimated to be over 100 times brighter than a galaxy. Yet in these Sloan Digital Sky Survey discovery images the quasars appear faint because they are extremely distant.

The Gamma Ray Sky
12.01.2002

What if you could see gamma rays? If you could, the sky would seem to be filled with a shimmering high-energy glow from the most exotic and mysterious objects in the Universe.

BHR 71: Stars, Clouds, and Jets
27.01.2003

What is happening to molecular cloud BHR 71? Quite possible, a binary star system is forming inside. Most stars in our Galaxy are part of binary star systems, but few have ever been seen in formation.

GRB Fireball Persists
17.09.1997

It's still there. The optical counterpart to the instantly famous gamma-ray burst (GRB) that occurred last February 28th has faded - but not completely. The astronomical community had waited patiently for months...

The Hubble Deep Field
7.06.1998

Galaxies like colorful pieces of candy fill the Hubble Deep Field - humanity's most distant yet optical view of the Universe. The dimmest, some as faint as 30th magnitude (about four billion times fainter...