Looking for warm dark matter

In the last century, astronomers studying the motions of galaxies and the character of the cosmic microwave background radiation came to realize that most of the matter in the universe was not visible. About 84% of the matter ...

Why is the night sky black?

It sounds obvious. That's what night is. The sun has set and when you look up at the sky, it's black. Except where there's a star, of course. The stars are bright and shiny.

NGC 6240: Colossal hot cloud envelopes colliding galaxies

(Phys.org) —Scientists have used Chandra to make a detailed study of an enormous cloud of hot gas enveloping two large, colliding galaxies. This unusually large reservoir of gas contains as much mass as 10 billion Suns, ...

The survivors of a 13 billion year old massacre

(PhysOrg.com) -- Our Milky Way galaxy is surrounded by some 200 compact groups of stars, containing up to a million stars each. At 13 billion years of age, these globular clusters are almost as old as the universe itself ...

A cosmic exclamation point

(PhysOrg.com) -- VV 340, also known as Arp 302, provides a textbook example of colliding galaxies seen in the early stages of their interaction. The edge-on galaxy near the top of the image is VV 340 North and the face-on ...

Atoms-for-Peace: A galactic collision in action (w/ Video)

(PhysOrg.com) -- European Southern Observatory astronomers have produced a spectacular new image of the famous Atoms-for-Peace galaxy (NGC 7252). This galactic pile-up, formed by the collision of two galaxies, provides an ...

Image: A Galactic Spectacle

A beautiful new image of two colliding galaxies has been released by NASA's Great Observatories. The Antennae galaxies, located about 62 million light-years from Earth, are shown in this composite image from the Chandra X-ray ...

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