io9: chandra

The Center Of The Milky Way Galaxy Shows The Birth And Death Of Suns

Charlie Jane Anders — Wed, 23 Sep 2009 07:30:00 PDT

The center of our galaxy shines in greater detail than ever before, in this new composite image from NASA's Chandra X-Ray Observatory. (Click to enlarge.) The whole gamut of stellar evolution is here, from bright young stars to black holes.

The diffuse X-ray light suffusing the image comes from gas that has been heated by stellar explosions, massive young stars — and outflows powered by the supermassive blackhole at the heart of the galaxy, Sagittarius A. Scientists believe Sagittarius A gave off giant X-ray flares 50 years and 300 years earlier. (So when we finally visit the center of the galaxy searching for the mythical planet Sha-Ka-Ree in order to meet God and ask him why he wants a spaceship, we should time our visit to avoid one of those irregular X-ray bursts.) [Chandra]

One Galaxy Smashes Into Four Others At 2 Million Miles Per Hour

Charlie Jane Anders — Tue, 14 Jul 2009 10:09:33 PDT

Stephan's Quintet sounds like the name of a nice jazz group, but this galactic cluster, discovered 250 years ago, is actually one galaxy passing through four others at nearly 2 million miles per hour. Hence the long tails. [Chandra Observatory]

Galactic Cluster Collision Divides Ordinary Matter from Dark Matter

Ed Grabianowski — Fri, 29 Aug 2008 08:00:00 PDT

Almost six billion years ago, two of the largest gravitational structures in the universe slammed into each other with velocities in the millions of miles per hour. Galactic clusters are collections of galaxies (sometimes thousands of them) that seem to hang together in violation of the known laws of physics. Not only did this ancient collision result in a stunningly beautiful image, but it's given astrophysicists an important clue about the nature of dark matter.

The image above is a composite, combining data from the Hubble Space Telescope with x-ray imagery from the Chandra X-Ray Observatory. Hubble captured the blue areas by detecting the gravitational lensing of light shining around the cluster. Dark matter in the cluster is causing the lensing. The pink area is a mass of hot gas, made of ordinary matter, which radiates the x-rays detected by Chandra.

What's amazing about the image is how clearly it shows that the dark matter separated from the ordinary matter when the clusters collided. The gases interacted with each other gravitationally, causing them to slow down and "pile up" in the middle of the clusters. The dark matter evidently did not interact with itself, sliding to the outer edges of the clusters. Astronomers think the mass of all this dark matter is what holds clusters together - without it, the galaxies are moving too fast to stay together. The cluster collision provides a lot of direct evidence that dark matter exists. Image by: NASA/ESA.

You can see the full image in high-resolution here.

Collision of galaxy clusters captured by astronomers. [EurkeAlert!]

The Largest Nuclear Explosion In History

charliejane — Tue, 01 Jan 2008 09:50:23 PST

A star 150 times larger than our own sun detonated in the biggest supernova ever recorded, as shown in this NASA illustration from May. This appears to be a new type of supernova, one which obliterates a massive star instead of creating a black hole. Photo by M. Weiss/NASA/CXC via Getty Images