physics news

http://www.nytimes.com/2001/08/15/sc...rchpv=nytToday

AUG 15, 2001

Cosmic Laws Like Speed of Light Might Be Changing, a Study Finds

By JAMES GLANZ and DENNIS OVERBYE

An international team of astrophysicists has discovered that the basic laws of nature as understood today may be changing slightly as the universe ages, a surprising finding that could rewrite physics textbooks and challenge fundamental assumptions about the workings of the cosmos.

The researchers used the world's largest single telescope to study the behavior of metallic atoms in gas clouds as far away from Earth as 12 billion light years. The observations revealed patterns of light absorption that the team could not explain without assuming a change in a basic constant of nature involving the strength of the attraction between electrically charged particles.

If confirmed, the finding could mean that other constants regarded as immutable, like the speed of light, might also have changed over the history of the cosmos.

The work was conducted by scientists in the United States, Australia and Britain and was led by Dr. John K. Webb of the University of New South Wales in Sydney, Australia. It is to be published on Aug. 27 in the field's most prestigious journal, Physical Review Letters.

Scientists who have examined the paper have not been able to find any obvious flaws. But because the consequences for science would be so far-reaching and because the differences from the expected measurements are so subtle, many scientists are expressing skepticism that the discovery will stand the test of time, and say they will wait for independent evidence before deciding whether the finding is true.

On the other hand, the finding would fit with some theorists' new views of the universe, particularly the prediction that previously unknown dimensions might exist in the fabric of space.

Even scientists on the project have been deliberately cautious in presenting their result. Describing the implications of what his team observed, Dr. Webb said, "It's possible that there is a time evolution of the laws of physics."

Dr. Webb added, "If it's correct, it's the result of a lifetime."

Dr. Rocky Kolb, an astrophysicist at the Fermi National Accelerator Laboratory who was not involved in the work, said the finding could not only force revisions in cosmology, the science of how the universe began and later evolved, but also add credence to an unproven theory of physics called string theory, which predicts that extra dimensions exist.

"The implication, if it is true, would just be so enormous that it's something people should look at and take seriously," Dr. Kolb said. "This would upset the apple cart."

The magnitude of the change apparently observed by the group is minute, amounting to just 1 part in 100,000 in a number called the fine structure constant over 12 billion years. That constant, also referred to as alpha, is defined in terms of more familiar quantities like the speed of light and the strength of electronic attractions within atoms.

But even that small change would rock physics and cosmology, said Dr. Sheldon Glashow of Boston University, who received a Nobel Prize in physics in 1979. The importance of such a discovery, Dr. Glashow said, would rank "10 on a scale of 1 to 10."

Considering the unexpected nature of the finding, both Dr. Glashow and Dr. Kolb said the chances were high that some more mundane explanation for the results would turn up.

Dr. John Bahcall, an astrophysicist at the Institute for Advanced Study in Princeton, N.J., said the complicated analysis that was required to infer the tiny changes from the observations could — in principle, at least — be obscuring possible errors.

"The effect does not scream out at you from the data," Dr. Bahcall said. "You have to get down on all fours and claw through the details to see such a small effect."

But others said that the team had been very careful and that any unknown source of error would have to be extremely subtle to be missed.

"If they were claiming anything less dramatic, probably most people would find their work very careful and believable," said Dr. Massimo Stiavelli, an astrophysicist at the Space Telescope Science Institute in Baltimore.

"Exceptional results deserve extraordinary proof," Dr. Stiavelli said, adding that he was reserving judgment until further evidence became available.

The work relied on observations of light from distant beacons called quasars, which shine with a brightness equivalent to billions of suns. The light is probably emitted by matter torn from young galaxies by the powerful gravity of a black hole.

Besides Dr. Webb, the team included three other scientists at the University of New South Wales, Michael T. Murphy, Dr. Victor V. Flambaum, and Dr. Vladimir A. Dzuba; and one physicist at Cambridge University in Britain, Dr. John D. Barrow. Three American astronomers who are experts on quasars were also members of the team: Dr. Christopher W. Churchill of Pennsylvania State University; Dr. Jason X. Prochaska of the Carnegie Observatories; and Dr. Arthur M. Wolfe of the University of California at San Diego.

The observations, made by the 30- foot-wide Keck Telescope on Mauna Kea, in Hawaii, looked in detail at the absorption of quasar light by gas clouds in deep space between Earth and the quasars. Metal atoms like zinc and aluminum are often present in trace amounts in the clouds.

The absorption of light by such atoms creates dark spikes at various wavelengths in the quasar's spectrum, with a pattern so well defined that it is often likened to a fingerprint. The value of those wavelengths is directly related to the value of the fine structure constant.

But the fingerprint seemed to change in time, Mr. Murphy said, indicating that the constant grows larger as one goes nearer to the present and was not really constant.

"What we have found is that, statistically, there is a difference between the fine structure constant a long time ago and here on earth," he said.

Far from being of interest only in understanding atomic behavior, said Dr. Barrow of Cambridge University, the effect would be important "because it gives you such a feedback into fundamental physics."

String theory, for example, could accommodate changes in quantities that accepted physics theory considers immutable. String theorists postulate that space contains tiny, unseen dimensions. Any change in the size of those dimensions — much like the expansion of the universe in the space we are familiar with — could change quantities like the fine structure constant, said Dr. Paul Steinhardt, a physicist at Princeton University.

Dr. Steinhardt said most theorists would have expected those changes to have occurred in the first seconds of the universe's life and be virtually unobservable by astronomers today. Still, he pointed out that several years ago, other astronomers unexpectedly found that the present universe is apparently filled with a mysterious kind of energy that counteracts gravity on large scales. Perhaps the two effects are somehow related, Dr. Steinhardt said.

Other scientists pointed out that geologic processes, like naturally occurring nuclear fission, have been used to determine that the fine structure constant has probably changed little over the past two billion years on Earth. But researchers on the new paper point out that their results reach back much farther in time, and that interpreting the geological results is also a complicated matter.

But a few physicists, like Dr. Jacob D. Bekenstein of Hebrew University in Israel, noted that some theories have long been predicting a change in some of nature's apparent constants. Dr. Bekenstein called the findings "potentially revolutionary" and said he was inclined to believe them.

"After much thinking about this issue," Dr. Bekenstein said, "I think the quasar observations may have found the real variation."

[Nicobie]

Originally posted by eclectica
http://www.nytimes.com/2001/08/15/sc...rchpv=nytToday



"After much thinking about this issue," Dr. Bekenstein said, "I think the quasar observations may have found the real variation."

Oh he does, does he?

[mike4947]

Do we have another "cold fusion" in the making? Everyone goes crazy to publish it seems, every time a new observation is made. In the "publish or perish" mode, no one is willing to wait to get coaboration on an observation.

Originally posted by mike4947
Everyone goes crazy to publish it seems, every time a new observation is made.

Yeah, but Mike, isn't the discovery interesting?

It's all about the preservation of one's own "intellectual property".

[mike4947]

Originally posted by eclectica
It's all about the preservation of one's own "intellectual property".

No it's about getting your name in print and being able to add it to your resume. No "published list"...... no grants, no "teaching assistants", no invites to the "better" cocktail parties, no year long sabaticals.

[Nicobie]

That's right.

1/2 this stuff makes 0 sence.

Bunch O blag.

[nanook]

Originally posted by Nicobie
That's right.

1/2 this stuff makes 0 sence.

Bunch O blag.

it's hard to comprehend, but as Belle says it is quite interesting.

those guys deserve to go to all the best cocktail parties.

i can't wait to see what more they can come up with concerning these findings.

i find it very interesting.

thanks, eclectica

[Bright Eyes]

I would venture to predict that the speed of light will be found to have decreased, rather than have increased or fluctuated up and down.

I would be interested to know the actual facts of this find, divorced from the scientists' hypothesis to explain the facts.

Explain why you think so, bright eyes. Is it because the Universe really isn't expanding, but staying the same size, and light is taking longer to travel across the whole thing, so we think that it's expanding?

Does the speed of light vary depending where you are in the Universe?

[nanook]

Originally posted by eclectica
Does the speed of light vary depending where you are in the Universe?

good question.

and maybe you know eclectica.........is the speed of light's actual "speed" affected by the gravitational pull of the massive objects in the universe, as it passes by?

this would include black holes, massive stars, and a clustered galaxy, lacking in much of this "dark matter", they are also in the process of investigating.

and who knows what else is actually out there, when we are talking "billions" of light years away.

there could be objects whose dimensions could boggle the mind and have never been encountered in any depth, shape or form???????????????

such wonderfully, awing questions.........and the answers can only leave me utterly speachless.

[mike4947]

Originally posted by nanook

and who knows what else is actually out there, when we are talking "billions" of light years away.

there could be objects whose dimensions could boggle the mind and have never been encountered in any depth, shape or form???????????????

and don't forget, that billions of light years also means billions of years ago. It'll be billions of years before what's happening there now get to us.

[nanook]

Originally posted by mike4947


and don't forget, that billions of light years also means billions of years ago. It'll be billions of years before what's happening there now get to us.

another good and unfathomable factazoid.

while i have you here mikey........here's one i've always wondered about that pertains to your comment.

let's say a ray of light from a star, about 1 million years ago, streams through the universe to reach the lens of your or my eyes.

let's say that once it has travelled and that light has reached our vision, why does it continue to shine?

i figure that 1 million years ago, (the point in the past in which this star actually resides) the star might actually be burnt out, by the time it took for that one ray to reach us, 1 million light years (in the future).

do you get what i'm saying?????

how many times does the rays from this star actually travel that 1 million light years. and why do we still continue to see it.

say like the constellations.

will they eventually cease to shine in the sky.

or does this "ray", from head to tail, sort to speak, span the entire distance of 1 million years, and we continue to see that entire ray.

is the ray actually, 1 million light years in length, as well?

[mike4947]

Originally posted by nanook


another good and unfathomable factazoid.

while i have you here mikey........here's one i've always wondered about that pertains to your comment.

let's say a ray of light from a star, about 1 million years ago, streams through the universe to reach the lens of your or my eyes.

let's say that once it has travelled and that light has reached our vision, why does it continue to shine?

i figure that 1 million years ago, (the point in the past in which this star actually resides) the star might actually be burnt out, by the time it took for that one ray to reach us, 1 million light years (in the future).

do you get what i'm saying?????

how many times does the rays from this star actually travel that 1 million light years. and why do we still continue to see it.

say like the constellations.

will they eventually cease to shine in the sky.

or does this "ray", from head to tail, sort to speak, span the entire distance of 1 million years, and we continue to see that entire ray.

is the ray actually, 1 million light years in length, as well?

Just to confuse you a little more here's a few facts

Light rays aren't rays, they are particles called photons, so what you're seeing is a bunch of photons that left the star a million years ago.
Why does it continue to shine, cause it's still putting out those little photons for everyone to make a wish on.

So if the star burns out, say today, we'll find it out a million years from now

As for burning out, yup, they will, stars are a big thermonuclear explosion that just happens to have enough boom to keep going for billions of years; But, sooner or later they'll go out with a bang, [Nova], a big bang [Super Nova] and leave a little thing called a white or brown dwarf, or maybe a black hole.

But seeing as how I'm a member of the Flat Earth Society I think it all been made up.

I'm not too sure, but I'll try to figure out the ray.

It is indeed 1 million light years in length. You can think of it as one long moving line of cars. Or perhaps think of it as a continuous stream. Such a stream may look like a single connected thread, but the thread analogy is wrong because what happens at the beginning supposedly doesn't affect what happens at the end. In other words, the star turning off its lights now wouldn't affect the light that was already emitted 1 million years ago, which we're seeing just now. Also, if the star turned off the lights temporarily, it would just create a gap in this thread-like-looking ray of light.

But then again, I'm not too sure. Maybe it is one long thing, and the end of it has some effect on the beginning of it, in ways that we haven't discovered yet. But to believe so, would be to believe that some things can travel faster than the speed of light.

[nanook]

okay, i understand the photons, mikey.

i guess i just wonder how many of these streams of photons have actually died. when the star went supernova, that many millions of years ago.

so............let's say, eclectica, that the stream, ray, whatever, does span the entire one million years.

we see the first inklings of it.

and continue seeing the same light, from the same star, because this stream has an entire length of one million years.

so, indeed, one day, some of our constellations will cease to exist.

although, that could be another million years in the future, depending on the size and distance of these stars.

if you guys keep answering me, i'm going to eventually whip out all my books and start scanning and we'll have an astronomy class going here.

cause, i could certainly go on and on and on........

kinda like a stream of photons from five million light years ago.

okay..........how many actual years is equal to one light year.

then we can actually fathom how far away these stars really are, eh?

[mike4947]

a light year isn't a measure of time, it's a measure of distance, it is the distance a photon will travel in one sidereal year. Figure 186,000 miles per second X 60 seconds x 60 minutes X 24 hours X 365.25 days = a whole shit load of miles. Apx 5.87 x 10 to the 12 power 5,870,000,000,000 or almost 6 trillion miles.

So if that little photon has been traveling for a million years, you can see why contacting a race that lived around that star has some difficulties attached to it.


and I refuse to go back and try to remember calculus and quantum mechanics for the astronomy course. I used to love watching the jocks sign up for it looking for a "gut" course.

nanook
if you guys keep answering me, i'm going to eventually whip out all my boobs and start stripping and we'll have an astronomy class going here, with uranus and yourblackhole.

cause, i could certainly go on and on and on........

[nanook]

Originally posted by eclectica

now that would be fathomable.


good way to end that discussion, eh?

yes, i'm speechless.

but it will never end my endless questions and wonders of the universe beyond, my dear eclectica.......muuuwwaaaaahhaaaa!!!



and a to you mikey.
a little brain candy for me to ponder for a little while.

but i'll be back, bumping this thread, you wait.