Dark Dust and Colorful Clouds near Antares
27.08.2019

Why is the sky near Antares and Rho Ophiuchi so dusty yet colorful? The colors result from a mixture of objects and processes. Fine dust illuminated from the front by starlight produces blue reflection nebulae. Gaseous clouds whose atoms are excited by ultraviolet starlight produce reddish emission nebulae.

Electric Night
4.12.2019

It may appear, at first, like the Galaxy is producing the lightning, but really it's the Earth. The featured nighttime landscape was taken from a southern tip of the Italian Island of Sardinia in early June.

NGC 1365: Majestic Island Universe
22.12.2022

Barred spiral galaxy NGC 1365 is truly a majestic island universe some 200,000 light-years across. Located a mere 60 million light-years away toward the faint but heated constellation Fornax, NGC 1365 is a dominant member of the well-studied Fornax Cluster of galaxies.

APOD: 2023 August 23 Б The Meteor and the Galaxy
23.08.2023

It came from outer space. It -- in this case a sand-sized bit of a comet nucleus -- was likely ejected many years ago from Sun-orbiting Comet Swift-Tuttle, but then continued to orbit the Sun alone.

APOD: 2024 December 22 Б The Local Fluff
22.12.2024

The stars are not alone. In the disk of our Milky Way Galaxy, about 10 percent of visible matter is in the form of gas called the interstellar medium (ISM). The ISM is not uniform and shows patchiness even near our Sun.

A Quasar Portrait Gallery
9.03.2002

Quasars (QUASi-stellAR objects) lie near the edge of the observable Universe. Discovered in 1963, astronomers were astounded that such objects could be visible across billions of light-years, as this implies they must emit prodigious amounts of energy. Where does the energy come from?

Mt Etna Lava Plumes
31.03.2003

Mt. Etna has been erupting for hundreds of thousands of years. Located in Sicily, Italy, the volcano produces lava fountains over one kilometer high. Mt. Etna is not only one of the most active...

Orion s Belt Continued
11.02.2009

Yesterday's skyscape featured Alnitak, Alnilam, and Mintaka, the stars of Orion's Belt. Today's also presents the easternmost belt star, Alnitak, at the bottom right of the field, surrounded by the well-known Horsehead and Flame nebulae.

Herschel Views the Milky Way
2.09.2011

With a 3.5 meter diameter mirror, larger than the Hubble Space Telescope, ESA's Herschel Space Observatory explores the Universe at infrared wavelengths. Herschel is named for German-born British astronomer Frederick William Herschel who discovered infrared light over 200 years ago.

M1: The Crab Nebula from Hubble
16.08.2015

This is the mess that is left when a star explodes. The Crab Nebula, the result of a supernova seen in mysterious filaments. The filaments are not only tremendously complex, but appear to have less mass than expelled in the original supernova and a higher speed than expected from a free explosion.