December Moon Meets Evening Star
9.12.2005

If you've been outdoors near sunset, then you've probably noticed Venus low in the west as the brilliant evening star. Sometimes mistaken for a tower light near the horizon, Venus is the third brightest celestial beacon, after the Sun and Moon, in planet Earth's sky.

A Meteor Moment
17.12.2010

Intensely bright, this fireball meteor flashed through Tuesday's cold, clear, early morning skies over the Karakas Mountains in central Iran, near the peak of the annual Geminid Meteor Shower. To capture the meteor moment and wintery night skyscape, the photographer's camera was fixed to a tripod, its shutter open for about 1.5 minutes.

The Terraced Night
6.02.2014

Long after sunset on January 25 an unusually intense red airglow floods this south-looking skyscape. The scene was recorded with a long exposure using a digital camera over Yunnan Province in southwest China. At best faintly visible to the eye, the lingering airglow is due to chemiluminescence, the production of light through chemical excitation.

M1: The Crab Nebula from Hubble
9.09.2018

This is the mess that is left when a star explodes. The Crab Nebula, the result of a supernova seen in 1054 AD, is filled with mysterious filaments. The filaments are not only tremendously...

Henize 70: A Superbubble in the LMC
4.02.2019

Massive stars profoundly affect their galactic environments. Churning and mixing interstellar clouds of gas and dust, stars -- most notably those upwards of tens of times the mass of our Sun -- leave their mark on the compositions and locations of future generations of stars.

APOD: 2023 December 4 Б Plane Crossing Crescent Moon
4.12.2023

No, the Moon is not a bow, and no, it did not shoot out a plane like an arrow. What is pictured is a chance superposition. The plane's contrail would normally appear white...

Aristarchus' Unbelievable Discoveries
14.09.1996

Here lived one of the greatest thinkers in human history. Aristarchus lived on the Greek island of Samos, a small island in the center of the above picture that can be identified with a good map.

GRO J1655 40: Evidence for a Spinning Black Hole
8.05.2001

In the center of a swirling whirlpool of hot gas is likely a beast that has never been seen directly: a black hole. Studies of the bright light emitted by the swirling gas frequently indicate not only that a black hole is present, but also likely attributes.

Searchlight Beams from the Egg Nebula
29.01.1996

The dramatic and mysterious looking object revealed in this Hubble Space Telescope image is known as the Egg Nebula. It is an aging star about 3,000 lightyears distant, entering its Planetary Nebula phase of evolution.

Vega
15.07.1997

Vega is a bright blue star 25 light years away. Vega is the brightest star in the Summer Triangle, a group of stars easily visible summer evenings in the northern hemisphere. The name Vega...