Posted on 04/25/2013 1:10:04 PM PDT by SeekAndFind
Scientists have subjected Albert Einstein's famous theory of gravity to its toughest real-world test so far—and it has prevailed.
Einstein's general theory of relativity states that objects with mass cause a curvature in space-time, which we perceive as gravity. Space-time, according to Einstein's theories of relativity, is a four-dimensional fabric woven together by space and time.
For example, a bowling ball causes a dent in a mattress, and that dent changes the otherwise straight motion of a nearby marble on the same mattress. Similarly, the mass of the sun distorts the space-time around it. A body with less mass, like the earth, travels along one path in that distorted space, which we call its orbit.
Scientists aren't testing the general theory because they think it is wrong but rather because they are certain it can't be the final explanation—just as Isaac Newton's notion of gravitational force was superseded by Einstein's explanation.
Einstein's theory of gravity, published nearly a century ago, has passed every test it has been subjected to. Nonetheless, scientists have been trying to pin down precisely at what point Einstein's theory of gravity breaks down, and where an alternative explanation will have to be devised. Einstein's framework for his theory of gravity, for example, is incompatible with quantum theory, which explains how nature works at an atomic and subatomic level.
Consider that for a black hole, Einstein's theory "predicts infinitely strong gravitational fields and density. That's nonsensical," said Paulo Freire, an astrophysicist at the Max Planck Institute for Radioastronomy in Germany and co-author of the study, which appears in the journal Science.
(Excerpt) Read more at online.wsj.com ...
FROM ASTRONOMICAL OBSERVATIONS:
Dr. Freire and his colleagues put Einstein to the test in a cosmic laboratory 7,000 light years from earth, where two exotic stars are circling each other.
One, known as a white dwarf, is the cooling remnant of a much lighter star. Its companion is a pulsar, which spins 25 times every second. Though the pulsar is just 12 miles across, it weighs twice as much as the sun.
“When you have such a big mass in such a small space you have extremely high gravity,” said Charles Wang, a theoretical physicist at the University of Aberdeen, Scotland, who wasn’t involved in the study.
The gravity on the pulsar’s surface is 300 billion times as great as the gravity on Earth. The conditions there approach the relentless, overwhelming power of a black hole, which swallows even light.
“We’re testing Einstein’s theory in a region where it has never been tested before,” said Dr. Freire.
The pulsar and white dwarf pair emit gravitational waves and the binary star system gradually loses energy. As a result, the stars will move closer to each other and orbit faster.
Einstein’s theory suggests the stars’ orbital periods—the time they take to go around each other—ought to shrink by about eight-millionths of a second per year.
Dr. Freire’s and his colleagues used several telescopes to take precise measurements about the two-star system. Their results perfectly matched the Einstein-based prediction.
Though Einstein’s framework remains intact so far, “the study is significant for the way observations by astronomers are helping to identify new, extreme cases” to test his general theory of gravity, said Dr. Wang.
A good case has been made for the theory that gavity pushes rather than pulls.
Very interesting. Thanks for posting.
I personally think gravity may be the key to interstellar travel.
Another interesting phenomenon of physics is that if you look from outer space, you can tell where Michael Moore is by looking for the dent in the earth.
For some reason the old theme to "Star Trek" just popped up in my head.
There is no gravity -- the Earth sucks.
</oldie but goodie>
Too heavy for me.
I personally think gravity may be the key to interstellar travel.
Me too, but I admit I’m not an expert. ;-)
Gravity is an oddball. We’re all familiar with it but its still very much unexplained.
Personally, I try to ignore gravity. Don’t like it, don’t have any use for it.
:: the earth, travels along one path in that distorted space, which we call its orbit ::
Which many folks (including Eistein) ^implied^ is that the Earth could “fly a tangent” at any moment if it weren’t for the laws of gravity.
In “every-man language”, this translates to: If Obama could ignore, repeal or even defund the laws of gravity, the “erff” would go screaming off into the Milky Way to its sure destruction.
All praise be to Obama [piss be upon him!]
I’m willing to bet that it breaks down at the quantum level.
Exactly! They claim they are repeatedly testing Einstein to "determine where his theory breaks down" then a few sentences later say "it breaks down at the quantum level".
To the experimenters: "so then you already KNOW where it breaks down then, right?" ---Asked in a Judge Judy type voice, full of sarcasm and contempt.
Honestly I don't understand the reasoning here. Or maybe they should just admit they like testing it 'cuz it's fun. (After all what's not cool about bending light and altering the flow of time? Nothing!)
Now for a real fun question: Quote, "Consider that for a black hole, Einstein's theory 'predicts infinitely strong gravitational fields and density. That's nonsensical,' said Paulo Freire..."
Why's that so 'nonsensical', hmm? :) After all, if any measurable mass is crushed into a single one dimensional point, wouldn't that by definition make its density "infinite"? And we better hope its gravity would be infinite too, or else we might have another universe on our hands and that would be one too many IMO (I already don't like my neighbors)....
Einstein’s classic thought experiment involves sitting on a train travelling at the speed of light. If you hold a mirror in front of your face, will you see your reflection in a mirror?
http://www.youtube.com/watch?v=vVKFBaaL4uM
That bad boy is definitely whipping around. Figure 40 mile circumference, so 480 miles per second, or over a million miles per hour for someone standing on the surface.
...of course there wouldn’t be much left of that person as they would weigh something like 5 trillion pounds...but then again, you’ll need to be that heavy to keep from flying off the object.
...I do like Earth.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.