Posted on 04/24/2002 6:30:34 PM PDT by longshadow
By Paul Recer
AP Science Writer
Wednesday, April 24, 2002; 4:21 PM
WASHINGTON –– The universe is about 13 billion years old, slightly younger than previously believed, according to a study that measured the cooling of the embers in ancient dying stars.
Experts said the finding gives "very comparable results" to an earlier study that used a different method to conclude that the universe burst into existence with the theoretical "Big Bang" between 13 and 14 billion years ago.
Harvey B. Richer, an astronomer at the University of British Columbia, said the Hubble Space Telescope gathered images of the faintest dying stars it could find in M4, a star cluster some 7,000 light years away.
Richer said the fading stars, called white dwarfs, are actually burnt out coals of stars that were once up to eight times the size of the sun. After they exhausted their fuel, the stars collapsed into Earth-sized spheres of cooling embers that eventually will turn cold and wink out of sight.
Earlier studies had established the rate of cooling for these stars, said Richer. By looking at the very faintest and oldest white dwarfs possible, astronomers can use this cooling rate to estimate the age of the universe.
Speaking at a news conference Wednesday, Richer said the dimmest of the white dwarfs are about 12.7 billion years old, plus or minus about half a billion years.
Richer said it is estimated that star formation did not begin until about a billion years after the Big Bang. He said this means his best estimate for age of the universe is "about 13 billion years."
Three years ago, astronomers using another method estimated the age at 13 to 14 billion years. That was based on precise measurements of the rate at which galaxies are moving apart, an expansion that started with the Big Bang. They then back-calculated – like running a movie backward – to arrive at the age estimate.
"Our results are in very good agreement" with Richer's estimate, said Wendy L. Freedman, an astronomer at the Carnegie Observatories in Pasadena, Calif., and a leader of the group performing the universe age calculations three years ago.
Bruce Margon, an astronomer at the Space Telescope Science Institute, said both conclusions are based on "a lot of assumptions" but the fact that two independent methods arrived within 10 percent of the same answer is important.
"To find an independent way to measure the age and then get essentially the same answer is a fantastic advance," said Margon. It may not be the final answer for the universe's age, he said, but is "very, very, very close."
To get the new age estimate, the Hubble Space Telescope collected light from M4 for eight days over a 67-day period. Only then did the very faintest of the white dwarfs become visible.
"These are the coolest white dwarf stars that we know about in the universe," said Richer. "These stars get cooler and cooler and less luminous as they age."
He added: "We think we have seen the faintest ones. If we haven't, then we'll have to rethink" the conclusions.
The faintest of the white dwarfs are less than one-billionth the apparent brightness of the dimmest stars visible to the naked eye.
M4 is a globular cluster, thought to be the first group of stars that formed in the Milky Way galaxy, the home galaxy for the sun, early in the history of the universe. There are about 150 globular clusters in the Milky Way; M4 was selected because it is closest to Earth.
The new age estimate for the universe is the latest in a long series of attempts to measure the passage of time since the Big Bang. Edwin Hubble, the famed astronomer who first proved that the universe is uniformly expanding, estimated in 1928 that the universe was two billion years old.
Later studies, using the very expansion that Hubble discovered, arrived at an estimate of about nine billion years for the universe age. This created a paradox for astronomers because some stars were known to be more ancient and it is impossible for stellar bodies to be older than the universe where they formed.
Freedman and others then determined, using proven values for the brightness and distance of certain stars, that the universe throughout its history has not expanded at a constant rate. Instead, the separation of galaxies is actually accelerating, pushed by a poorly understood force known as "dark energy." By adding in calculations for this mysterious force, the Freedman group arrived at the estimate of 13 to 14 billion years.
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On the Net:
Hubble Images: http://oposite.stsci.edu/pubinfo/pr/2002/10
NASA: http://www.nasa.gov
Then I'd say that the anti-intellectual left has achieved its purpose.
Which is exactly what the Astronomers have done here:
First, several groups of astronomers developed methodologies based on the Hubble expansion to estimate the age of the Universe. There value was about 14 billion years, plus or minus a billion or so.
This is then used as the basis of a prediction: the prediction is that a completely different methodology (one that does NOT rely on measuring the expansion of the Universe, or things related thereto) for measuring the age of the Universe should give the same result.
The experiment conducted by the Canadian scientists (when they weren't busy at "curling practice" at the local ice arena) was to see if this prediction is correct.
The result: it IS correct!
[snip] In fact, I'd just as soon fund wymyn's studies as quantum physics.
Who's stopping you?
If you have a beef with the claimed accuracy of the measurements regarding the age of the Universe, by all means post the evidence. This thread is over 150 post long, and not a single naysayer has provided a scintilla of evidence that the methods used by the scientists were defective.
The skepticism would be much more useful if the skeptics could specify which of the observations of astronomy and cosmology they dispute, and state the specific reasons for the dispute. If you accept the observed data but doubt the conclusions, it would be very interesting if you would provide us with an alternative model which better accommodates the data. That's how the game is played.
First of all, weather prediction, cancer, AIDS and the common cold are all very hard problems compared to measuring the age of the universe. The latter is simply a matter of undergraduate math and a sufficiently powerful telescope. Second of all, the scientists who work on one problem are not the same people who work on any other. What you've said is rather like upbraiding a dentist for the slow pace of research into treating pancreatic cancer.
I certainly hope they are willing to accept skepticism of their claims.
Certainly, as long as it's backed by substantive thought.
Forsooth, the Church forbade them from thinking otherwise.
As a practical matter, there really weren't any scientists around before Copernicus. Stargazers, yes; mathematicians, yes; but not scientists -- as we use the term. Not too many were around after Galileo either, certainly not in the lands ruled by the Inquisition, as they all fled to the north. Science is a relatively new human endevour.
[to which you replied] Who's stopping you?
Actually, I already pay for both. So do you, if you're a taxpayer.
Through coercive taxation and overflowing government grants, I am forced to fund both wymyn's studies and quantum physics. All education should be privatized.
In my view, both departments--wymyn's studies and quantum physics--produce drivel of similar uselessness. Both contribute equally (i.e., nil) to the betterment of man.
[to which you replied] Then I'd say that the anti-intellectual left has achieved its purpose.
Hmmm...I must disagree. Is it not well established that most major universities are replete with leftist professors?
Further, wasn't one of physics' icons, the late Carl Sagan (currently a resident of Hades, in my estimation), an avowed anti-Reagan leftist?
Isn't Steven Hawking a bit of a Clintonista?
Sorry, no one of that name is or was an icon of physics.
I doubt we will ever find out.......
That's probably because they aren't. I personally don't doubt the intelligence of these people and what they're doing. My only argument that hasn't been refuted either is that they're only measuring what they can see. If there are galaxies or other objects in space farther out than what we can now detect, objects whose light is too faint, or hasn't reached us yet, that would throw their whole discoveries out of whack, because that would mean the universe is older than what they're saying. That's why I'm skeptical of stories like this.
I say wait 20 or 30 more years when technology advances with even better telescopes. You'll be hearing the universe is at least a 100 billion years older or more.
On this, I am in full agreement with you.
In my view, both departments--wymyn's studies and quantum physics--produce drivel of similar uselessness. Both contribute equally (i.e., nil) to the betterment of man.
Well, one out of two isn't bad. I agree that "wymyn's studies" and other PC claptrap is essentially useless garbage.
But QM on the other hand is extremely useful. Do you think we would have personal computers, the internet, and a myriad of other electronic devices and technologies if we did NOT study and understand QM?
How so? IF there were objects further away that we can't see, how does that make the Universe older that what has been measured?
I say wait 20 or 30 more years when technology advances with even better telescopes. You'll be hearing the universe is at least a 100 billion years older or more.
I dare say that would be extraordinarily unlikely, as I'm quite sure there are observational data that place an UPPER bound on the possible age of the Universe, and that bound is much lower than 100 billion years. I wish I could remember the exact observational data that tell us this, but at the moment I can't recall what it is. Perhaps "Physicist" knows.....
Yeah and when he made his discovery they all probably thought he was a nut case who should be committed to a mental hospital.
Like h*ll it is, you SLIMER!
WE all know you're just positioning yourself to get reply # 200!
;-)
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