Ninety Gravitational Wave Spectrograms and Counting
7.12.2021

Every time two massive black holes collide, a loud chirping sound is broadcast out into the universe in gravitational waves. Humanity has only had the technology to hear these unusual chirps for the past seven years, but since then we have heard about 90 -- during the first three observing runs.

APOD: 2026 March 10 Б Sky Glows over Paranal Observatory
10.03.2026

Are lasers from giant telescopes being used to defend the Earth? No. Lasers shot from telescopes are now commonly used to help increase the accuracy of astronomical observations. In some directions, Earth atmosphere-induced fluctuations in starlight can indicate how the air mass over a telescope is changing, but in other directions, no bright star exists.

Galaxies Beyond the Heart: Maffei 1 and 2
9.03.2010

The two galaxies on the far left were unknown until 1968. Although they would have appeared as two of the brighter galaxies on the night sky, the opaque dust of the central band of our Milky Way Galaxy had obscured them from being seen in visible light.

Views from Cassini at Saturn
18.06.2017

What has the Cassini orbiter seen at Saturn? The featured music video shows some of the early highlights. In the first time-lapse sequence (00:07), a vertical line appears that is really Saturn's thin rings seen nearly edge-on. Soon some of Saturn's moon shoot past.

Four Lasers over Mauna Kea
23.06.2014

Are lasers from giant telescopes being used to attack the Galactic center? No. Lasers shot from telescopes are now commonly used to help increase the accuracy of astronomical observations. In some sky locations, Earth...

NGC 4696: Energy from a Black Hole
27.04.2006

In many cosmic environments, when material falls toward a black hole energy is produced as some of the matter is blasted back out in jets. In fact, such black hole "engines" appear to be the most efficient in the Universe, at least on a galactic scale.

Zodiacal Light before Dawn
11.09.2014

You might not guess it, but sunrise was still hours away when this nightscape was taken, a view along the eastern horizon from a remote location in Chile's Atacama desert. Stretching high into...

An Ultraviolet Image of M101
27.06.1995

This giant spiral galaxy, Messier 101 (M101), was photographed by the Ultraviolet Imaging Telescope onboard the Space Shuttle Endeavour during the Astro-2 mission (March 2 - 18, 1995). The image has been computer processed so that the colors represent the intensity of ultraviolet light.

In Motion: Uranus and Moons
30.11.2021

What's that moving across the sky? A planet just a bit too faint to see with the unaided eye: Uranus. The gas giant out past Saturn was tracked earlier this month near opposition -- when it was closest to Earth and at its brightest.

Three Planets in Dawn Skies
9.12.2006

Three children of the Sun rise in the east in this peaceful dawn skyview recorded December 7th near Bolu, Turkey. Inner planet Mercury, fresh from its second transit of the 21st century, stands highest in the bright sky at the top right. Gas giant Jupiter lies below the cloud bank near picture center.