Universe Unfolding More Rapidly

Drachir

Science fiction fantasy
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Western Canada. Born in England. English mother
An interesting article. Apparently the Milky Way galaxy in not only larger than previoulsy thought, but actually has four arms; not two. This creates some interesting consequences in the future.

The universe is unfolding more quickly than we thought

Our tiny blue planet is going 160,000 km/h faster than previously clocked


Tom Spears, Ottawa Citizen; Canwest News Service

Published: 2:03 am
Our planet -- along with the whole solar system -- is rushing through space 160,000 kilometres per hour faster than we thought, says a new analysis of Earth's place in the universe.
Oh, and the risk of crashing into something really big -- like another galaxy -- is apparently much higher than what was previously thought, too.
The findings are part of a new look at our galaxy, the Milky Way, which is actually harder to see than far-off galaxies because we're inside it. In some regions, the glare is blinding to telescopes.
Earth's revised speed: 965,000 kilometres per hour in an orbit around the Milky Way's centre.
And since we and our neighbouring stars are moving faster than previously thought, yet we're not being flung off into space, astronomers have re-calculated the mass that holds all that speeding stuff together. Result: the Milky Way must be some 50 per cent heavier than they had previously figured.
Being heavier means that our galaxy has more gravity, and is therefore pulling harder on neighbouring galaxies such as Andromeda. That raises the chance that some day, they will crash together, though not for a few billion years.
The findings come from German and American astronomers using the U.S. National Science Foundation's Very Long Baseline Array radio telescope to rewrite the map of the Milky Way. The array is a network of 10 radio-telescope antennas stretching from Hawaii to New England and the Caribbean.
They reported their results Monday at the American Astronomical Society's meeting in California.
Even the shape of the Milky Way is a surprise, says Mark Reid of the Harvard-Smithsonian Center for Astrophysics. The old theory was that our galaxy is a spinning disk, with two arms spiralling out from the centre on opposite sides.
"These (new) measurements indicate that our galaxy probably has four, not two, spiral arms of gas and dust that are forming stars," he said.
This illustrates a problem of astronomy: that some of the biggest mysteries lie close to home.
"Because we're inside it, it's difficult for us to determine the Milky Way's structure," he said. "For other galaxies, we can simply look at them and see their structure, but we can't do this to get an overall image of the Milky Way. We have to deduce its structure by measuring and mapping."
Earth is in one of the spiral arms, so far from the galaxy's centre that it takes 28,000 light years to travel that distance. The whole galaxy has at least 200 billion stars, and possibly 400 billion.



© The Edmonton Journal 2009
 
Thanks for this, Drachir. Very interesting.

One point, if we have four spiral arms not two wouldn't that make the Milky Way unique? I don't think I've ever seen a picture of a galaxy with four arms.
 
The number of arms in a spiral galaxy is not set in stone, it just changes its classification. Currently the galaxy is thought to have a bar structure through its center, so two arms would be the norm, and four would be unusual. Remove the bar and anything is possible.

I believe the galaxy may turn out to have 6 maybe more arms. Rather than being formed in the galaxy, some of these will turn out to be artifacts of previously absorbed smaller galaxies
 
Um, surely that puts paid to a lot of 'missing mass' ??

IMHO, Dark Matter, MACHOs and a whole heap of dubious stuff just joined the dole-queue...

I wonder if MoND, 'Modified Newtonian Dynamics', will survive when the mass-budget is hastily recalculated...
 
Very interesting article. Thanks for posting!

Seems we were off quite a bit with our original estimates as to the size of the Milky Way. Saying it's 50% heavier than we thought, thats quite a bit!

Would any of this effect the size of the black hole at the center of the galaxy? Would it be bigger than originally thought as well?
 
Very interesting article. Thanks for posting!

Seems we were off quite a bit with our original estimates as to the size of the Milky Way. Saying it's 50% heavier than we thought, thats quite a bit!

Would any of this effect the size of the black hole at the center of the galaxy? Would it be bigger than originally thought as well?

Not really, because that is a seperate set of calculations. By examining the stars and gas cloud orbiting the hole, they can get a pretty good gauge on things.

Basically the size of the black hole does not establish the size of the galaxy
 

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