The Deep Sky Toward Andromeda
8.09.2021

What surrounds the Andromeda galaxy? Out in space, Andromeda (M31) is closely surrounded by several small satellite galaxies, and further out it is part of the Local Group of Galaxies -- of which our Milky Way galaxy is also a member.

Sun Halo at Winter Solstice
14.01.2002

Sometimes it looks like the Sun is being viewed through a large lens. In the above case, however, there are actually millions of lenses: ice crystals. As water freezes in the upper atmosphere, small, flat, six-sided, ice crystals might be formed.

Cassini to Venus
3.07.2004

Saturn Orbiter Cassini with Titan Probe Huygens attached rocketed into early morning skies on October 15, 1997. The mighty Titan 4B Centaur rocket is seen here across the water, arcing away from Launch Complex 40 at Cape Canaveral Air Station.

Dry Ice Sled Streaks on Mars
17.06.2013

What creates these long and nearly straight grooves on Mars? Dubbed linear gullies, they appear on the sides of some sandy slopes during Martian spring, have nearly constant width, extend for as long as two kilometers, and have raised banks along their sides.

Crossing Dingo Gap on Mars
18.02.2014

An important threshold on Mars has now been crossed. Landing in mid-2012, the Curiosity rover is searching for clues of whether life could ever have existed on the red planet. Recent findings of Curiosity include evidence for an ancient (but now dried) freshwater lake, and the non-detection of the biomarker methane in the Martian atmosphere.

APOD: 2024 November 19 Б Undulatus Clouds over Las Campanas Observatory
19.11.2024

What's happening with these clouds? While it may seem that these long and thin clouds are pointing toward the top of a hill, and that maybe a world-famous observatory is located there, only part of that is true.

Gliese 581 and the Habitable Zone
26.04.2007

The faint, unremarkable star centered in this skyview is Gliese 581, a mere 20 light-years away toward the constellation Libra. But astronomers are now reporting the discovery of a remarkable system of three planets orbiting Gliese 581, including the most earth-like planet found beyond our solar system.

Kepler s Streak
9.03.2009

Streaking skyward, a Delta II rocket carries NASA's Kepler spacecraft aloft into the clear night of March 6. The dramatic scene was recorded in a time exposure from the crowded pier in Jetty Park at the northern end of Cocoa Beach, Florida, about 3 miles from the Cape Canaveral launch site.

Sun Halo over Sweden
1.01.2018

What's happened to the Sun? Sometimes it looks like the Sun is being viewed through a giant lens. In the featured video, however, there are actually millions of tiny lenses: ice crystals. Water may freeze in the atmosphere into small, flat, six-sided, ice crystals.

APOD: 2025 March 18 Б LDN 1235: The Shark Nebula
18.03.2025

There is no sea on Earth large enough to contain the Shark nebula. This predator apparition poses us no danger as it is composed only of interstellar gas and dust. Dark dust like that featured here is somewhat like cigarette smoke and created in the cool atmospheres of giant stars.