When Z is for Mars
14.04.2023

A composite of images captured about a week apart from mid August 2022 through late March 2023, this series traces the retrograde motion of ruddy-colored Mars. Progressing from lower right to upper left Mars...

APOD: 2025 June 9 Б Between Scylla and Charybdis: A Double Cosmic Discovery
8.06.2025

Can you identify this celestial object? Likely not Б because this is a discovery image. Massive stars forge heavy elements in their cores and, after a few million years, end their lives in powerful supernova explosions. These remnants cool relatively quickly and fade, making them difficult to detect.

APOD: 2025 September 11 Б The Umbra of Earth
10.09.2025

The dark, inner shadow of planet Earth is called the umbra. Shaped like a cone extending into space, it has a circular cross section most easily seen during a lunar eclipse.

APOD: 2025 October 1 Б NGC 6960: The Witchs Broom Nebula
30.09.2025

Ten thousand years ago, before the dawn of recorded human history, a new light would suddenly have appeared in the night sky and faded after a few weeks. Today we know this light was from a supernova, or exploding star, and record the expanding debris cloud as the Veil Nebula, a supernova remnant.

CMBR Dipole: Speeding Through the Universe
8.10.2006

Our Earth is not at rest. The Earth moves around the Sun. The Sun orbits the center of the Milky Way Galaxy. The Milky Way Galaxy orbits in the Local Group of Galaxies. The Local Group falls toward the Virgo Cluster of Galaxies.

Orion: Head to Toe
23.10.2010

Cradled in cosmic dust and glowing hydrogen, stellar nurseries in Orion the Hunter lie at the edge of a giant molecular cloud some 1,500 light-years away. Spanning nearly 25 degrees, this breath-taking vista stretches across the well-known constellation from head to toe (left to right).

3C294: Distant X Ray Galaxy Cluster
21.02.2001

Large clusters of galaxies are the most massive objects in the universe. Astronomers now realize that a hallmark of these cosmic behemoths are gas clouds with temperatures of tens of millions of degrees that pervade the clusters and radiate strongly in x-rays.

Opportunity Rockets Toward Mars
22.09.2003

Next stop: Mars. Two months ago, the second of two missions to Mars was launched from Cape Canaveral, Florida, USA above a Boeing Delta II rocket. The Mars Exploration Rover dubbed Opportunity is expected to arrive at the red planet this coming January.

Messier 43
9.07.2015

Often imaged but rarely mentioned, Messier 43 is a large star forming region in its own right. It's just part of the star forming complex of gas and dust that includes the larger, more famous neighboring Messier 42, the Great Orion Nebula.

IC 418: The Spirograph Nebula
10.06.2017

What is creating the strange texture of IC 418? Dubbed the Spirograph Nebula for its resemblance to drawings from a cyclical drawing tool, planetary nebula IC 418 shows patterns that are not well understood. Perhaps they are related to chaotic winds from the variable central star, which changes brightness unpredictably in just a few hours.