Anemic Galaxy NGC 4921 at the Edge
9.02.2009

How far away is spiral galaxy NGC 4921? Although presently estimated to be about 320 million light years distant, a more precise determination could be coupled with its known recession speed to help humanity better calibrate the expansion rate of the entire visible universe.

Signed, "A Black Hole"
16.05.1997

This artistic image is actually the signature of a supermassive black hole in the center of distant galaxy M84 - based on data recently recorded by Hubble's new Space Telescope Imaging Spectrograph (STIS). Very...

What are Comet Tails Made Of?
26.03.1996

The tail of comet Hyakutake, visible in this recent color image, is composed of dust and gas driven off the icy comet nucleus by the Sun's heat and blown away by the solar wind. Bathed in solar ultraviolet light, the gas molecules break down and are excited, producing a characteristic glow.

Crab Pulsar Wind Nebula
27.12.2008

The Crab Pulsar, a city-sized, magnetized neutron star spinning 30 times a second, lies at the center of this remarkable image from the orbiting Chandra Observatory. The deep x-ray image gives the first clear view of the convoluted boundaries of the Crab's pulsar wind nebula.

Anemic Spiral NGC 4921 from Hubble
25.11.2013

How far away is spiral galaxy NGC 4921? Although presently estimated to be about 310 million light years distant, a more precise determination could be coupled with its known recession speed to help humanity better calibrate the expansion rate of the entire visible universe.

The Spinning Pulsar of the Crab Nebula
21.08.2022

At the core of the Crab Nebula lies a city-sized, magnetized neutron star spinning 30 times a second. Known as the Crab Pulsar, it is the bright spot in the center of the gaseous swirl at the nebula's core.

APOD: 2024 March 18 Б Comet Pons Brooks Swirling Coma
18.03.2024

A bright comet will be visible during next month's total solar eclipse. This very unusual coincidence occurs because Comet 12P/Pons-Brooks's return to the inner Solar System places it by chance only 25 degrees away from the Sun during Earth's April 8 total solar eclipse.

Clusters, Hartley, and the Heart
14.10.2010

An alluring Comet Hartley 2 cruised through planet Earth's night sky on October 8, passing within about a Full Moon's width of the famous double star cluster in Perseus. The much anticipated...

APOD: 2025 August 24 Б The Spinning Pulsar of the Crab Nebula
24.08.2025

At the core of the Crab Nebula lies a city-sized, magnetized neutron star spinning 30 times a second. Known as the Crab Pulsar, it is the bright spot in the center of the gaseous swirl at the nebula's core.

APOD: 2025 July 17 Б 3I/ATLAS
17.07.2025

Discovered on July 1 with the NASA-funded ATLAS (Asteroid Terrestrial-impact Last Alert, System) survey telescope in Rio Hurtado, Chile, 3I/ATLAS is so designated as the third known interstellar object to pass through our Solar System It follows 1I/йOumuamua in 2017 and the comet 2I/Borisov in 2019.