Universe Might be Bigger and Older than Expected

[Dragon Star]

A project aiming to create an easier way to measure cosmic distances has instead turned up surprising evidence that our large and ancient universe might be even bigger and older than previously thought.

If accurate, the finding would be difficult to mesh with current thinking about how the universe evolved, one scientist said.

A research team led by Alceste Bonanos at the Carnegie Institution of Washington has found that the Triangulum Galaxy, also known as M33, is about 15 percent farther away from our own Milky Way than previously calculated.

The finding, which will be detailed in an upcoming issue of Astrophysical Journal, suggests that the Hubble constant, a number that measures the expansion rate and age of the universe, is actually 15 percent smaller than other studies have found.

Currently, most astronomers agree that the value of the Hubble constant is about 71 kilometers per second per megaparsec (a megaparsec is 3.2 million light-years). If this value were smaller by 15 percent, then the universe would be older and bigger by this amount as well.

Scientists now estimate the universe to be about 13.7 billion years old (a figure that has seemed firm since 2003, based on measurements of radiation leftover from the Big Bang) and about 156 billion light-years wide.

The new finding implies that the universe is instead about 15.8 billion years old and about 180 billion light-years wide.

http://www.space.com/scienceastronom...le_revise.html

Quite interesting.

[Blue Fire]

Interesting, Yes! It's a good example of how the scientific process naturally questions and corrects itself through observation, study, and experimentation. In any case though, what's a few billions years here and there, even if it does mean we've got 24 billion more light years to play around in?

[Dragon Star]

Well, the problems arise for judging the origin of the universe based on age and expansion rate. If it becomes too old, or too young, then it can throw current theories out the window.

[Blue Fire]

Okay, don't these astronomers need to make up their minds? How, exactly does this fit in in with:
http://www.universetoday.com/2006/08...bble-constant/

Chandra Confirms the Hubble Constant
August 8th, 2006

Nearly every single astronomical measurement depends on the Hubble constant, a number that calculates the expansion of the Universe. NASA’s Chandra X-Ray Observatory recently measured this value independently, and came up with a similar number - 77 km per second per megaparsec (3.26 million light-years to the megaparsec). Give or take 15%. This confirms that the Universe is still between 12 and 14 billion years old.

[stuart]

Most measurements these days say that the Hubble constant is around 70-75, but of course there are always those who disagree. I'm sure Alan Sandage, for example, is thrilled that this new stuff says it's lower, as he's been in the "Hubble constant = 50" camp for decades.

But I would think that ONE new line of evidence for a lower hubble constant is not going to change what most people say it is. Especially because so many other lines of evidence point towards the 70-75 number now-a-days, such as globular cluster ages.

[Dragon Star]

No, but the point is that it is subject to change and could be incorrect. Our current methods that say it is "yay old" might have flaws.

[stuart]

Originally Posted by Dragon Star

No, but the point is that it is subject to change and could be incorrect. Our current methods that say it is "yay old" might have flaws.

The point I was trying to make is that pretty much ALL of our current methods point to a certain age, and many of them are completely independent of the others. So I don't think that ONE new study is going to change the field overnight, but it could cause people to go back and re-examine the assumptions and analysis of the other methods to check for possible ways to make them agree with the new one, or the new one can be re-tested to see if it gets the same results as before (a more likely scenario, I think, than re-evaluating everything else).

[Dragon Star]

Right, that's my point exactly.

[stuart]

And where one project may show it's different, there's always another independent method that agrees with previous results: http://chandra.harvard.edu/press/06_...ss_080806.html

By combining X-ray data from Chandra with radio observations of galaxy clusters, the team determined the distances to 38 galaxy clusters ranging from 1.4 billion to 9.3 billion light years from Earth. These results do not rely on the traditional distance ladder. Bonamente and his colleagues find the Hubble constant to be 77 kilometers per second per megaparsec (a megaparsec is equal to 3.26 million light years), with an uncertainty of about 15%.

[Blue Fire]

Sigh . . . where will it all end? I follow these types of things with great interest, but it can get frustrating for us non-experts to decipher just where astronomers are going sometimes, . . . not to mention where they are coming from.