Galaxies Away
21.08.1999

This striking pair of galaxies is far, far away ... about 350 million light-years from Earth. Cataloged as AM0500-620, the pair is located in the southern constellation Dorado. The background elliptical and foreground spiral galaxy are representative of two of the three major classes of galaxies which inhabit our Universe.

A Year of Resolving Cosmology
30.12.2003

This year, humanity learned that the universe is 13.7 billion years old. Before this year, the universe's age was thought to be about 13 billion years, but really only constrained to be between about 12 billion and 15 billion years old.

James Webb Space Telescope over Earth
25.12.2021

There's a big new telescope in space. This one, the James Webb Space Telescope (JWST), not only has a mirror over five times larger than Hubble's in area, but can see better in infrared light.

Sharpless 308: Star Bubble
24.12.2013

Blown by fast winds from a hot, massive star, this cosmic bubble is huge. Cataloged as Sharpless 2-308 it lies some 5,200 light-years away toward the constellation of the Big Dog (Canis Major) and covers slightly more of the sky than a Full Moon.

Helios Helium
20.05.1996

Above is an image of the relatively quiet Sun made on May 18 in light emitted by ionized Helium atoms in the Solar chromosphere. Helium was first discovered in the Sun in 1868, its name fittingly derived from from the Greek word Helios, meaning Sun. Credit for the discovery goes to astronomer Joseph Lockyer.

Rock Fingers on Mars
19.06.2022

There, just right of center, what is that? The surface of Mars keeps revealing new surprises with the recent discovery of finger-like rock spires. The small nearly-vertical rock outcrops were imaged last month by the robotic Curiosity rover on Mars.

APOD: 2024 December 10 Б The Great Meteor Storm of 1833
9.12.2024

It was a night of 100,000 meteors. The Great Meteor Storm of 1833 was perhaps the most impressive meteor event in recent history. Best visible over eastern North America during the pre-dawn hours...

Arp 78: Peculiar Galaxy in Aries
23.03.2022

Peculiar spiral galaxy Arp 78 is found within the boundaries of the head strong constellation Aries. Some 100 million light-years beyond the stars and nebulae of our Milky Way galaxy, the island universe is over 100,000 light-years across.

The Densest Galaxy
4.10.2013

The bright core and outer reaches of giant elliptical galaxy M60 (NGC 4649) loom large at the upper left of this sharp close-up from the Hubble Space Telescope. Some 54 million light-years away and 120,000 light-years across, M60 is one of the largest galaxies in the nearby Virgo Cluster.

APOD: 2025 April 6 Б Moonquakes Surprisingly Common
5.04.2025

Why are there so many moonquakes? Analyses of seismometers left on the moon during the Apollo moon landings reveal a surprising number of moonquakes occurring within 100 kilometers of the surface. In fact, 62 moonquakes were detected in data recorded between 1972 and 1977.