“Rare crash at the Milky Ways core” – Astronomy

Image of Milky Way galactic center by Swift X-ray telescope Source: Astronomy.com

Astronomy magazine has this report on the giant gas cloud that is headed for a ‘rare crash’ with the center of our galaxy.  I was surprised to find the theory that this gas cloud may contain a small star covered in the report.  Dr. Paul LaViolette has also theorized the potential for such hidden object.

The University of Michigan at Ann Arbor has been watching the gas clouds’ progression with the Swift X-ray telescope, according to the article supplied by them.   The ‘collision’ between what astronomers have named G-2 and the galactic center is expected to happen this Spring.  Here’s more from the report:

With NASA’s orbiting Swift telescope, the University of Michigan team is taking daily images of a mysterious gas cloud about three times the mass of Earth that’s spiraling toward the supermassive black hole at the Milky Way’s core. From our vantage point, the core lies more than 25,000 light-years away in the southern summer sky near the constellations Sagittarius and Scorpius.

In 2011, German astronomers discovered a gas cloud called G2. They expected it to hit the black hole called Sagittarius A* (pronounced “Sagittarius A-star”) late last year. That didn’t happen, but the cloud continues to drift closer. Astronomers now predict that the impact will occur in the next few months.

Astronomers have never seen anything like this, much less with a front-row seat.

“Everyone wants to see the event happening because it’s so rare,” said Nathalie Degenaar from the Department of Astronomy at the College of Literature, Science and the Arts.

Supermassive black holes are believed to lurk at the centers of all elliptical and spiral galaxies. The Milky Way’s, by comparison, is dim — about a hundred million times fainter than scientists might expect. It’s likely the more common variety, Degenaar said.

“We think that the fainter ones are the majority, but it’s very difficult to study those,” Degenaar said. “We just can’t see them. Ours is the only one we can study to understand what their role is in the universe.”

I appreciate the fact that the articles’ author used the word ‘believed’ to describe the theory of supermassive blackholes, as lately observation has shown that the centers of galaxies can dish out as much as they take in.   The author continues:

The Swift observatory is the only telescope providing daily updates at X-ray wavelengths where the crash will show up most profoundly, the researchers say. Those capabilities, coupled with a research tool developed by Mark Reynolds from the University of Michigan, will help provide the first evidence of the collision. This tool quickly analyzes changes in the X-ray brightness of images across days — a sudden increase could signal impact. It also immediately posts the images online.

While astronomers expect to see a change in brightness, they don’t know how dramatic it will be because they aren’t sure exactly what the gaseous G2 object is. If it’s all gas, the region would glow in the X-ray band for years to come as the black hole slowly swallows the cloud. But another possibility is that G2 could be shrouding an old star. If that’s the case, the display would be less spectacular as Sagittarius A* slurped from the cloud while the star slipped by, dense enough to fight its grasp.

“I would be delighted if Sagittarius A* suddenly became 10,000 times brighter. However it is possible that it will not react much — like a horse that won’t drink when led to water,” said Jon Miller from the University of Michigan. “If Sagittarius A* consumes some of G2, we can learn about black holes accreting at low levels, sneaking midnight snacks. It is potentially a unique window into how most black holes in the present-day universe accrete.”

Read the full report, click here.


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