M1: The Incredible Expanding Crab
5.09.2013

The Crab Nebula is cataloged as M1, the first on Charles Messier's famous list of things which are not comets. In fact, the Crab is now known to be a supernova remnant, an expanding cloud of debris from the explosion of a massive star.

From the Northern to the Southern Cross
26.01.2019

There is a road that connects the Northern to the Southern Cross but you have to be at the right place and time to see it. The road, as pictured here, is actually...

Mars over Duddo Stone Circle
22.03.2021

Why are these large stones here? One the more famous stone circles is the Duddo Five Stones of Northumberland, England. Set in the open near the top of a modest incline, a short hike across empty fields will bring you to unusual human -sized stones that are unlike anything surrounding them.

APOD: 2025 April 8 Б Moon Visits Sister Stars
7.04.2025

Sometimes, the Moon visits the Pleiades. Technically, this means that the orbit of our Moon takes it directly in front of the famous Pleiades star cluster, which is far in the distance. The technical...

Deimos Before Sunrise
23.05.2025

Deimos takes 30 hours and 18 minutes to complete one orbit around the Red Planet. That's a little more than one Martian day or sol which is about 24 hours and 40 minutes long, so Deimos drifts westward across the Martian sky.

APOD: 2025 November 12 Б A Super Lunar Corona
11.11.2025

What are those colorful rings around the Moon? A corona. Rings like this will sometimes appear when the Moon is seen through thin clouds. The effect is created by the diffraction of light around individual, similarly-sized water droplets in an intervening but mostly transparent cloud.

Gamma rays and Comet Dust
19.08.2016

Gamma-rays and dust from periodic Comet Swift-Tuttle plowed through planet Earth's atmosphere on the night of August 11/12. Impacting at about 60 kilometers per second the grains of comet dust produced this year's remarkably active Perseid meteor shower.

APOD: 2025 June 23 Б W5: Pillars of Star Formation
22.06.2025

How do stars form? Images of the star forming region W5 like those in the infrared by NASA's Wide Field Infrared Survey Explorer (WISE, later NEOWISE) satellite provide clear clues with indications that massive stars near the center of empty cavities are older than stars near the edges.

Jupiter's Dry Spots
12.06.1997

Known for its spectacular images of Jupiter's moons, Io, Ganymede, Callisto, and Europa, the robot spacecraft Galileo has also aggressively explored the Jovian atmosphere. In December of 1995, Galileo's atmospheric probe descended into Jupiter's clouds and reported a surprising absence of water.

Crater Wall on Solis Planum
30.09.2004

This dramatic perspective view looks south-east along the wall of a large eroded impact crater on Solis Planum, bordering the mountainous Thaumasia region of Mars. Stretching for about 50 kilometers into the scene, the crater wall is around 800 meters high.