Thursday, January 13, 2011

That Green 'Blob' in space: What is it?

The green blob found in space by a 24-year old teacher. (Photo taken using Hubble Telescope). The latest interpretation is that it's really a collision of two galaxies similar to the Milky Way.

A mammoth millions of light years wide "green blob" appears to have captured the attention of the astronomical world, prompting the key question: What IS it? Evidently, it's clearly not dark matter (since it's visible - see photo) and certainly not a manifestation of dark energy. Meanwhile, The Hubble Space Telescope got its first peek at a mysterious giant green blob and found that it's strangely alive.

Well, not literally like "the Blob" of movie fame, but rather the bizarre glowing blob is giving birth to new stars, some only a couple million years old, in remote areas of the universe where stars don't normally form. The blob of gas was first discovered by a Dutch school teacher in 2007 and is named Hanny's Voorwerp (HAN'-nee's-FOR'-vehrp). Voorwerp is Dutch for object.

NASA released the new Hubble photo Monday at the American Astronomical Society meeting in Seattle. Parts of the green blob are collapsing and the resulting pressure from that is creating the stars. As we know (see earlier blogs on stellar evolution) when a massive plasma -gas cloud is subject to gravitational attractive forces - say introduced by a powerful external agent- the cloud collapses in a spherical shape, forming a proto-star. These are what we call "embryonic" stars.

The stellar nurseries observed in the green blob, however, are outside of a normal galaxy, which is usually where stars live. That makes these "very lonely newborn stars" that are "in the middle of nowhere," according to Bill Keel, the University of Alabama astronomer who examined the blob.

The blob is the size of our own Milky Way galaxy and it is 650 million light years away. Each light year is about 6 trillion miles. The blob is mostly hydrogen gas swirling from a close encounter of two galaxies and it glows because it is illuminated by a quasar in one of the galaxies. A quasar is a bright object full of energy powered by a black hole.

Hanny van Arkel, who was 24 at the time, discovered the blob as part of a worldwide Galaxy Zoo project where everyday people can look at archived star photographs to catalog new objects.
Van Arkel said when she first saw the odd object in 2007 it appeared blue and smaller. The Hubble photo provides a clear picture and better explanation for what is happening around the blob.

"It actually looked like a blue smudge," van Arkel told The Associated Press. "Now it looks like dancing frog in the sky because it's green." She says she can even see what passes for arms and eyes.

All animist analogies aside, the latest take from galactic specialists is that the "blob" is actually a collision of two galaxies similar to the Milky Way. The radiation given off from the collision is predominantly confined to certain excited atoms of oxygen which accounts for the greenish hue.

Any aliens caught in that collision? We can't say, but we do hope they're far enough away from the major crunching and field interactions to survive.

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