ASTRONOMERS CRUNCH NUMBERS, UNIVERSE GETS BIGGER

Ohio State University ^ | 03 August 2006 | Staff (press release)

[PatrickHenry]

That intergalactic road trip to Triangulum is going to take a little longer than you had planned.

An Ohio State University astronomer and his colleagues have determined that the Triangulum Galaxy, otherwise known as M33, is actually about 15 percent farther away from our galaxy than previously measured.

This finding implies that the Hubble constant, a number that astronomers rely on to calculate a host of factors -- including the size and age of the universe -- could be significantly off the mark as well.

That means that the universe could be 15 percent bigger and 15 percent older than any previous calculations suggested.

The astronomers came to this conclusion after they invented a new method for calculating intergalactic distances, one that is more precise and much simpler than standard methods. Kris Stanek, associate professor of astronomy at Ohio State, and his coauthors describe the method in a paper to appear in the Astrophysical Journal (astro-ph/0606279).

In 1929, Edwin Hubble formulated the cosmological distance law that determines the Hubble constant. Scientists have disagreed about the exact value of the constant over the years, but the current value has been accepted since the 1950s. Astronomers have discovered other cosmological parameters since then, but the Hubble constant and its associated methods for calculating distance haven't changed.

"The Hubble constant used to be the one parameter that we knew pretty well, and now it's lagging behind. Now we know some things quite a bit better than we know the Hubble constant," Stanek said. "Ten years ago, we didn't even know that dark energy existed. Now we know how much dark energy there is -- better than we know the Hubble constant, which has been around for almost 80 years."

Still, Stanek said he and his colleagues didn't start this work in order to change the value of the Hubble constant. They just wanted to find a simpler way to calculate distances.

To calculate the distance to a faraway galaxy using the Hubble constant, astronomers have to work through several complex steps of related equations, and incorporate distances to closer objects, such as the Large Magellanic Cloud.

"In every step you accumulate errors," Stanek said. "We wanted an independent measure of distance -- a single step that will one day help with measuring dark energy and other things."

The new method took 10 years to develop. They studied M33 in optical and infrared wavelengths, checking and re-checking measurements that are normally taken for granted. They used telescopes of all sizes, from fairly small 1-meter telescopes to the largest in the world -- the 10-meter telescopes at the Keck Observatory in Hawaii .

"Technologically, we had to be on the cutting edge to make this work, but the basic idea is very simple," he said.

They studied two of the brightest stars in M33, which are part of a binary system, meaning that the stars orbit each other. As seen from Earth, one star eclipses the other every five days.

They measured the mass of the stars, which told them how bright those stars would appear if they were nearby. But the stars actually appear dimmer because they are far away. The difference between the intrinsic brightness and the apparent brightness told them how far away the stars were -- in a single calculation.

To their surprise, the distance was 15 percent farther than they expected: about 3 million light-years away, instead of 2.6 million light-years as determined by the Hubble constant.

If this new distance measurement is correct, then the true value of the Hubble constant may be 15 percent smaller -- and the universe may be 15 percent bigger and older -- than previously thought.

"Our margin of error is now 6 percent, which is actually pretty good," Stanek said. Next, they may do the same calculation for another star system in M33, to reduce their error further, or they may look at the nearby Andromeda galaxy. The kind of binary systems they are looking for are relatively rare, he said, and getting all the necessary measurements to repeat the calculation would probably take at least another two years.

[Co-author info and funding sources omitted from original article.]

[Old Professer]

I suppose that means the price of a roundtrip ticket's going up by 30% now.

[RightWhale]

Okay. I hadn't heard it before, or if I had heard it, it didn't register. But then probably a lot hasn't registered in my mental metric as yet.

[Diamond]

That means that the universe could be 15 percent bigger and 15 percent older than any previous calculations suggested.

Bummer.

Cordially,

[Coyoteman]

Science is an intellectual dead end. It's a lot of little guys in tweed suits cutting up frogs on foundation grants.

I just joined the thread and found your post.

I hope this was in jest, because if not you are making an absolute fool of yourself.

[MilesMonroe]

"I hope this was in jest, because if not you are making an absolute fool of yourself."

I don't know enough to be incompetent.

[Coyoteman]

"I hope this was in jest, because if not you are making an absolute fool of yourself."

I don't know enough to be incompetent.

From this reply, I assume you were jesting. Glad to hear it.

Welcome to FR.

[zeugma]

Bump for later read

[dinoparty]

re: "I don't know enough to be incompetent."

I think this was a further slam on scientists who "know alot" of junk but don't know anyhting of importance and are incompetent at anything worthwhile.

[Hoosier-Daddy]

The proof of Bell's Theorem, for starters.

[dinoparty]

Which is what?

[Hoosier-Daddy]

Basically, that our universe at the quantum level is non-local, i.e. in order for our universe to maintain cohesiveness on a quantum level, information must be transmitted at speeds greater than that of light or in the case of Bell's Theorem, instantaneously. The information would be transmitted across higher dimensions and would appear instantaneous to the observer. David Boehm wrote a great book on the concept called Wholeness and the Implicate Order. A much better explanation can be found here: www.fdavidpeat.com/bibliography/essays/healtech.htm

[longshadow]

An update on this article, from Ned Wright's website:

An Older but Larger Universe?

05 Aug 2006 - Ohio State astronomers have measured a new precise distance to the nearby galaxy M33 based on a spectroscopic eclipsing binary. Their value is 15% larger than the old Cepheid based distance. By itself this says nothing about the Hubble constant because M33 is so close to the Milky Way that its radial velocity is dominated by random motions, not the expansion of the Universe. But it could indicate that Cepheid distances are incorrect by 15%.

If so, the Hubble constant would be smaller: about 61 instead of 72 km/sec/Mpc. But the claim in the OSU press release that "the universe could be [...] 15 percent older" is incorrect. If the Hubble constant is lower, then CMB anisotropy data require that OmegaM, the ratio of the matter density to the critical density, be higher, so the vacuum energy is lower, and the change in the age of the universe is considerably smaller, as shown in graph at right

above [click on the graph to enlarge] which shows the age vs. Ho for CMB consistent models as the solid curve, and the 1/Ho behavior assumed by the OSU press release as the dashed curve. So the Universe would not be 15% older but perhaps 7% older.

The claim that the Universe would be 15% larger is partially incorrect. Even though relatively nearby galaxies would be 15% further away the actual size of the Universe would go from infinite (flat) to finite (closed) but very big, which is a smaller Universe. The distance to distant quasars at redshift z=6 would increase by only 4%, and the distance to the last scattering surface changes less than 0.5% because this is what is fixed by the CMB.

CNN quoting space.com and John Johnson of the LA Times accepted the press release's claims of a 15% older and larger Universe uncritically. The real news is that a new method for precision distance measurements has achieved its first result. It will be averaged in with other methods used to calibrate the Cepheid period-luminosity relation and lead to a few percent decrease in the Hubble constant.

One of the methods to be averaged will be the Sunyaev-Zeldovich effect which gives Ho = 77 +/- 10 km/sec/Mpc according to a recent paper. This agrees with the values of Ho from WMAP and HST quite well.

Elsewhere on his website, Ned notes other, more recent (?) research that tends to corroborate the current value of the the Hubble constant.

[PatrickHenry]

Thanks. Press releases are sometimes a bit unreliable, but I frequently post them because they are issued while the news is hot, they require no subscription (as the journals do), and there are never any copyright problems.