It's relative. Astronomers have been measuring spin precession in an eclipsing pair of pulsars.
Credit: Daniel Cantin/McGill University
Posted on 07/05/2008 5:49:29 PM PDT by neverdem
It's relative. Astronomers have been measuring spin precession in an eclipsing pair of pulsars.
Credit: Daniel Cantin/McGill University
As if his reputation needed cementing, astronomers have confirmed Albert Einstein's status as a supergenius once more. Studying a unique pair of pulsars--small and extremely dense leftovers from supernova explosions--researchers have measured an effect that was predicted by Einstein's 92-year-old general theory of relativity. The result, they report tomorrow in Science, is almost exactly what the famous physicist had foreseen.
In Einstein's relativistic universe, matter curves space and slows down time, and the speed of light remains the only constant. But those are the big effects. The theory of relativity also includes some more esoteric details, one of which is called spin precession. The idea goes like this: Two massive bodies orbiting near each other will warp space enough to disturb the central axis around which both are moving, causing them to begin wobbling just like spinning tops. Strong gravity creates this so-called precession, and the more massive the objects, the easier the precession is to observe.
It's not an easy theory to test. Researchers need two very dense objects orbiting very close together, and they have to be able to detect what is going on between them. Black holes are dense, but their event horizons preclude observations. The lack of candidates and telescopic power had frustrated astronomers for years, until the discovery in 2003 of a particular pair of pulsars. These asteroid-sized objects pack sunlike masses, extremely small orbits, and incredibly fast spins. They also emit powerful and ultraregular radio signals that are easily detectable with Earth-based dishes. Most important in this case, one pulsar eclipses the other briefly every couple of hours. That's key to detecting precession, because during each eclipse astronomers can determine the precise angle of the radio signal and therefore the pulsar's wobble over time.
For the past 4 years, an international team has been carefully tracking the signals of one of the pulsars and monitoring the signals' direction during eclipses--a observational technique "that has never been employed before," says astrophysicist and co-author Rene Breton of McGill University in Montreal, Canada. The researchers determined that the precession of the pulsar's orbital axis advances by 4.77 degrees per year, plus or minus 0.66 degrees. Calculations based on Einstein's theory predicted it should advance by 5.07 degrees per year, well within the margin of error.
"It's bang-on," says astrophysicist and Nobel laureate Joseph Taylor of Princeton University. "Einstein's theory passed the test this time," agrees astrophysicist Fotis Gavriil of NASA's Goddard Space Flight Center in Greenbelt, Maryland, who praises the study's "amazing high-precision measurement." So is Einstein's reputation secure? Says Gavriil, "Only with experiments like this will we know for sure."
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Einstein amazes me.
Me too!!
That guy who wrote the linked article is a complete crackpot!
Don’t let yourself get amazed too easily. Einstein said some dopey things, particularly about gravity.
“That guy who wrote the linked article is a complete crackpot!”
Perhaps, he just didn’t understand the gravity of the situation. :-)
Don’t let yourself get amazed too easily. Einstein said some dopey things, particularly about gravity.
“Einstein said some dopey things, particularly about gravity.”
Not being a physicist, I am surprised to hear that Einstein’s theory of gravitation has been disproved. What’s the story?
For another, Einstein stated that information could not be passed around faster than C whereas it is well known that gravity propagates instantaneously to within our ability to measure it.
If a missile is headed for that guy's house and I destroy it, that would be wrong.
I think I understand now.
Yea it took me off guard a bit but some of his work on global warming seems to be pretty good.
Wendy1946 has said some mighty dopey things about Physics here at FR. Like: "There’s never been a “big bang”, the universe is not expanding, and if dark matter or dark energy could be detected, it would not be dark. For that matter if the stuff were actually 95% of the universe as claimed, you’d be vacuuming it up off your carpets four or five times a day."
You're dead wrong about gravity affects being transmitted instantaneously - it is well known that gravity works at the speed of light just like all other fundamental force phenomenon.
Not being familiar with every last thing Einstein had to say about gravity, I can't say he didn't make any goofy statements there, but let's just say I hold him in slightly higher regard than you on the subject. (Massive, light-bending sarcasm there in case you didn't catch it....)
No, I don't have time to explain it, but you should read up on inertial frames. It all has to do with relativity - the relative frames w.r.t. each other., and gravity moves at the speed of light in each context.
Why does “the speed of light remain the only constant”?
Is there something special about photons within the universe of particles?
Is it the fact that humans have given the effect of photons the name “light” and found that the processing of light (”sight”) is the most useful of the human senses for survival?
Or is it because “light” is the first thing God created?
Inquiring minds....
lol...Tom Van Flandern? A crackpot’s crackpot. You’re embarrassing yoruself, Wendy.
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