ULXs in M74
30.03.2005

In visual appearance, M74 is a nearly perfect face-on spiral galaxy, about 30 million light-years away toward the constellation Pisces. The red blotches seen in this composite view are ultraluminous x-ray sources (ULXs) mapped by the Chandra X-ray Observatory.

Reflected Aurora Over Alaska
12.02.2013

Some auroras can only be seen with a camera. They are called subvisual and are too faint to be seen with the unaided eye. In the above image, the green aurora were easily visible to the eye, but the red aurora only became apparent after a 20-second camera exposure.

A Blue Bridge of Stars between Cluster Galaxies
15.07.2014

Why is there a blue bridge of stars across the center of this galaxy cluster? First and foremost the cluster, designated SDSS J1531+3414, contains many large yellow elliptical galaxies. The cluster's center...

Sunspot Group AR 2339 Crosses the Sun
29.06.2015

How do sunspots evolve? Large dark sunspots -- and the active regions that contain them -- may last for weeks, but all during that time they are constantly changing. Such variations were particularly apparent...

Kepler Orrery IV
5.12.2015

The exoplanet hunting Kepler mission's total for candidate and confirmed multiple planet systems stands at 1,705 worlds in orbit around 685 distant stars. Put all of those exoplanet orbits on the same scale and follow their relative orbital motions to get Kepler Orrery IV.

HI4PI: The Hydrogen Sky
24.10.2016

Where are the Milky Way's gas clouds and where are they going? To help answer this question, a new highest-resolution map of the sky in the universe's most abundant gas -- hydrogen -- has been completed and recently released, along with its underlying data.

Milky Way with Airglow Australis
3.02.2017

Captured last April after sunset on a Chilean winter's night an exceptionally intense airglow flooded this scene. The panoramic skyscape is also filled with stars, clusters, and nebulae along the southern Milky Way including the Large and Small Magellanic clouds.

Fortuitous Flash Candidate for the Farthest Star Yet Seen
11.04.2018

Was this flash the farthest star yet seen? An unexpected flash of light noticed fortuitously on Hubble Space Telescope images may prove to be not only an unusual gravitational lensing event but also an image of a normal star 100 times farther away than any star previously imaged individually.

X-Ray Wind From NGC 3783
1.06.2000

A black hole is supposed to inexorably attract matter. But the intense radiation generated as material swirls and plunges into its high gravity field also heats up surrounding gas and drives it away.

Abell 2218: A Galaxy Cluster Lens
10.07.1995

Sometimes one of the largest concentrations of mass known can act like a lens. Almost all of the bright objects in this image are galaxies in the cluster known as Abell 2218. The cluster...