When Black Holes Collide
20.10.2015

What happens when two black holes collide? This extreme scenario likely occurs in the centers of some merging galaxies and multiple star systems. The featured video shows a computer animation of the final stages of such a merger, while highlighting the gravitational lensing effects that would appear on a background starfield.

Lyrids in Southern Skies
27.04.2017

Earth's annual Lyrid meteor shower peaked before dawn on April 22nd, as our fair planet plowed through dust from the tail of long-period comet Thatcher. Seen from the high, dark, and dry Atacama desert a waning crescent Moon and brilliant Venus join Lyrid meteor streaks in this composited view.

Galaxies Away
25.05.2018

This stunning group of galaxies is far, far away, about 450 million light-years from planet Earth and cataloged as galaxy cluster Abell S0740. Dominated by the cluster's large central elliptical galaxy (ESO 325-G004)...

APOD: 2025 April 21 Б Galaxy Lenses Galaxy from Webb
21.04.2025

Is this one galaxy or two? Although it looks like one, the answer is two. One path to this happening is when a small galaxy collides with a larger galaxy and ends up in the center. But in the featured image, something more rare is going on.

The Large Cloud of Magellan (LMC)
23.10.1996

Magellan and his crew had plenty of time to study the southern sky during their famous voyage around the world. As a result, two fuzzy cloud like objects in the southern sky are now known as the Clouds of Magellan. These star clouds are small irregular galaxies, satellites of our larger Milky Way spiral galaxy.

Four Quasar Images Surround a Galaxy Lens
27.02.2017

An odd thing about the group of lights near the center is that four of them are the same distant quasar. This is because the foreground galaxy -- in the center of the quasar images and the featured image -- is acting like a choppy gravitational lens.

Galaxies Away
8.02.2007

This stunning group of galaxies is far, far away - about 450 million light-years from planet Earth - cataloged as galaxy cluster Abell S0740. Dominated by the cluster's large central elliptical galaxy (ESO 325-G004), this...

PG 1115+080: A Gravitational Cloverleaf
31.03.1999

All four blue images in the above photograph are the same object. The gravitational lens effect of the red, foreground, elliptical galaxy visible near image center creates a cloverleaf image of the single distant quasar. Light from the quasar is pulled around the massive galaxy in different paths, corresponding to different images.

Weak Lensing Distorts the Universe
30.03.2008

Is the distant universe really what it appears to be? Astronomers hope not. Intervening dark matter, which is normally invisible, might show its presence by distorting images originating in the distant universe, much the way an old window distorts images originating on the other side.

Spinning Black Holes and MCG 6 30 15
29.10.2001

What makes the core of galaxy MCG-6-30-15 so bright? Some astronomers believe the answer is a massive spinning black hole. If so, this would be the first observational indication that it is possible to make a black hole act like a battery -- and tap into its rotational energy.