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NASA Probe Validates Einstein Within 1%

kdawson posted more than 7 years ago | from the kind-of-a-drag dept.

Space 188

An anonymous reader writes "Gravity Probe B uses four ultra-precise gyroscopes to measure two effects of Einstein's general relativity theory — the geodetic effect and frame dragging. According to the mission's principal investigator, the data from Gravity Probe B's gyroscopes confirm the Einstein theory's value for the geodetic effect to better than 1%. In a common analogy, the geodetic effect is similar to the shape of the dip created when the ball is placed on to a rubber sheet. If the ball is then rotated, it will start to drag the rubber sheet around with it. In a similar way, the Earth drags local space and time around with it — ever so slightly — as it rotates. Over time, these effects cause the angle of spin of the satellite's gyroscopes to shift by tiny amounts." The investigators will be doing further data analysis over the coming months and expect to release final results late this year.

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Finally! That took long enough. (4, Interesting)

Animats (122034) | more than 7 years ago | (#18762597)

That project took way too long. I remember people working on it when I went through Stanford in the mid-1980s. It was something of a boondoggle; it mostly produced students, not flight hardware. I'm glad to hear it finally worked, though.

Re:Finally! That took long enough. (5, Informative)

schwartzg (1089259) | more than 7 years ago | (#18762675)

True, it did take a while. But I'd like to think it was worth the wait. Also, for those who care, here is a link to the Stanford page http://einstein.stanford.edu/ [stanford.edu] it has the same info as the article along with more stuff about the project.

Re:Finally! That took long enough. (1)

renegadesx (977007) | more than 7 years ago | (#18763407)

I don't think it really took TOO long. That above link is a good read, many kudos

Re:Finally! That took long enough. (0)

Anonymous Coward | more than 7 years ago | (#18762679)

it mostly produced students

I think it mostly produced ego from the project administration.http://www.aero.org/publications/cr osslink/summer2002/profile.html

Re:Finally! That took long enough. (5, Interesting)

A beautiful mind (821714) | more than 7 years ago | (#18762693)

Actually people have been preparing this experiment since the 1960s.

There was a great lecture about this on this year's hungarian skeptics conference, spiced with the real life experience that Hungary was part of the soviet influence sphere at that time, so when one physicist was allowed to go to the USA for a year to do research. When he came back, his colleagues were flocking him, discussing the news and that the americans are setting up this experiment. The lecturer, now an old man, can finally see the result of the experiment they were discussing more than 40 years ago.

Re:Finally! That took long enough. (2, Funny)

Anonymous Coward | more than 7 years ago | (#18762935)

This seems like a waste of money and resources. As any creationist will stress to you - gravity is only a THEORY.

Re:Finally! That took long enough. (5, Interesting)

Zaph0dB (971927) | more than 7 years ago | (#18763691)

Glad it worked? I'm horrified it worked.
Every time someone (re)validates Einstein relativity theories, we actually know we're one step further from FTL (Faster than light - though I'd be surprised if any /. geek wouldn't know the term) than we thought we were before.

Damm gravity.

Re:Finally! That took long enough. (4, Funny)

Eyeball97 (816684) | more than 7 years ago | (#18763885)

FTL? WTF? Everybody knows that FTL drives are a work of fiction.

No, my friend, what you need is a warp drive.

Well we still have wormholes (1)

arcite (661011) | more than 7 years ago | (#18765213)

Wormholes count for something don't they? ...now all we need to do is harness the power of the sun...

Re:Finally! That took long enough. (1)

TheGreatHegemon (956058) | more than 7 years ago | (#18764005)

This may almost sound Trollish, but I am by no mean a Physics major, and it shows in this.
Could anyone who actually is familiar with this overall project (Not a stats person, I'm sure they'll say it's insignificant) tell us if the margin of error is truly acceptable?
I understand that there is always a margin of error due to minimum measurable differences, but can physicists now go "Phew, we are now FULLY sure this is right, and not that there has been a measuring fluke" or is there still some doubt? I mean, it seems close, but one can never be sure in physics as to how closely it *has* to line up.

Re:Finally! That took long enough. (4, Interesting)

Tickletaint (1088359) | more than 7 years ago | (#18764751)

I don't think anyone's concerned about proving Einstein absolutely right or absolutely wrong—if you look at it in those terms, any theory is bound to be proved "wrong," eventually, in that it'll fail for some ever-increasing standard of precision. What's news here is that we can now trust Einstein's equations to predict our measured reality within that cited "1%," confirming that general relativity is a pretty damn useful model. But that doesn't mean it won't be supplanted next year by something even more useful.

Maybe it took so long... (1)

tinkerton (199273) | more than 7 years ago | (#18764411)

because nobody was waiting for the result? Any doubt concerning the theory will focus on other areas.

Within 1%? Well... (0, Troll)

Organic Brain Damage (863655) | more than 7 years ago | (#18762611)

...that's not good enough for Dick Cheney.

Re:Within 1%? Well... (1)

Proofof. Chaos (1067060) | more than 7 years ago | (#18765043)

Somebody please mod this up funny

Slashdot: my source for news about... (4, Funny)

gardyloo (512791) | more than 7 years ago | (#18762641)

... balls on rubber sheets. Seriously.

Re:Slashdot: my source for news about... (4, Funny)

Soko (17987) | more than 7 years ago | (#18762733)

You really know how to play to the worst in human nature, especially with the word "Probe" in TFA's title.

A tip o' the hat to you, sir.

Soko

Re:Slashdot: my source for news about... (1)

eclectro (227083) | more than 7 years ago | (#18762781)

It might be better than "beater in fudge brownie batter."

Re:Slashdot: my source for news about... (0)

Harmonious Botch (921977) | more than 7 years ago | (#18762811)

That joke is older than the experiment...

Re:Slashdot: my source for news about... (4, Insightful)

Plutonite (999141) | more than 7 years ago | (#18762995)

I was about to submit this BBC article, then saw the embarrassment over the wording would be too much and decided otherwise :)

But I find simplifying matters this way a very noble way of getting knowledge about the universe across to the layman. Without the balls-on-rubber-sheets, we would have to be talking about Riemann geometry and differentiable manifolds and other wonderful stuffs. There are reserved places in heaven for people who can make these kind of analogies. Millions of clueless joes will tell you so.

Virginia (-1, Offtopic)

Anonymous Coward | more than 7 years ago | (#18762663)

I guess it's time to repeal the second amendment, huh?
Anyone who doesn't support gun control shares responsibility for this tragedy. Libertarians, Republicans- you have blood on your hands today, every single one of you.

We will win in 2008, and you will lose your guns. And there isn't a damn thing you can do about it :)

Re:Virginia (0, Offtopic)

heinousjay (683506) | more than 7 years ago | (#18762727)

That's brave talk. You realize, of course, you're coming after people with guns, right?

Re:Virginia (2, Funny)

gardyloo (512791) | more than 7 years ago | (#18762809)

That's brave talk. You realize, of course, you're coming after people with guns, right?
Hey, if she's got a gun, she comes whenever she wants. I'm just along for the ride.

Re:Virginia (-1, Flamebait)

Anonymous Coward | more than 7 years ago | (#18763081)

That's brave talk. You realize, of course, you're coming after people with guns, right?

What of it? I think we've learned from the militia "movements" of the '90s is that you guys are all full of shit. Gun nuts are just dickless, gung-ho losers. Sure, some of your buddies might raise a stink here and there, but going by the Waco example, the government will be more than happy to bring them into compliance with the law. :)

Re:Virginia (-1, Offtopic)

heinousjay (683506) | more than 7 years ago | (#18763121)

I don't own a gun, Captain Assumption.

Re:Virginia (0, Offtopic)

Anonymous Coward | more than 7 years ago | (#18762825)

um, 5th amendment gaurantees freedom, chump.

see, back in the day when that was written, a rifle was the edge of technology. that amendment gaurantees that the government never has the power to absolutely control the people. that if the gov gets out of line, we can take the power back.

since, the government has gained access to much more powerful weapons while restricting access to citizens. now we have no control. we are free because the government 'lets us' be free. thats not how it should be.

MAYBE instead of blaming guns, you should blame the real problem. lack of parenting, lack of social skills, lack of proper psychological conditioning in the infuential years.

dont blame the tool, blame the user. responsibility for said user falls into the hands of parenting and education. america has failed in both respects, indisputably. the safest cities in the countries are the ones were gun ownership is required.

ALSO, if gun control becomes the platform, dont count on dems winning 2008. besides, its not like both parties arent retarded...

Re:Virginia (1)

OminousZ (1088565) | more than 7 years ago | (#18765109)

um, 5th amendment gaurantees freedom, chump.
"Where did you get that automatic weapon?" "I plead the 5th!"

Re:Virginia (1)

Proofof. Chaos (1067060) | more than 7 years ago | (#18765185)

It's the 2nd amendment, dumbass. Are we a little dyslexic.

Re:Virginia (1)

AnotherUsername (966110) | more than 7 years ago | (#18765341)

Sorry to feed the troll...

indisputably. the safest cities in the countries are the ones were gun ownership is required.

Because Compton and Detroit are bastions of safety...

Re:Virginia (0, Offtopic)

Anonymous Coward | more than 7 years ago | (#18762901)

And yet, similar tragedies occurs in nations that crack down on guns. As long as we have a brain, there will be weapons. It is the main reason why America is having a nightmare time in Iraq.

Now, as to having blood on my hand, well, let me point out that if only a few ppl who was around the gunman had had a gun, then it would never have been this magnitude. It is because students are not allowed to carry guns that this happened.

Re:Virginia (0)

Anonymous Coward | more than 7 years ago | (#18763221)

"Now, as to having blood on my hand, well, let me point out that if only a few ppl who was around the gunman had had a gun, then it would never have been this magnitude. It is because students are not allowed to carry guns that this happened."

That doesn't account for other effects of having more guns. If more students were allowed to carry guns, it is very likely that there would be more gun accidents, especially if not all the gun-toting students were properly trained. And in a high-density alcohol party environment like a dormitory, where this tragedy started, there is a real possibility that the number of fatalities from gun accidents or intentional murders would over time exceed the number of deaths from today's tragedy, making a no-gun policy actually safer.

If everybody has a gun, then the strategy of a criminal is simply to use theirs first. Especially if they think they might die anyway, as today. Increasing the number of guns doesn't help in that case.

Re:Virginia (0, Offtopic)

Anonymous Coward | more than 7 years ago | (#18763491)

If more people are armed then you get lower death counts in tragedies like these - since the shooter is more likely to be killed before the death count gets too high. However, you get more deaths in the smaller things - domestic disputes, drunken morons, etc.

Since large scale shootings are reasonably rare, I would suspect on balance reducing the smaller ones results in fewer deaths overall - but I'm guessing I have no numbers...

Re:Virginia (0)

Anonymous Coward | more than 7 years ago | (#18763043)

Outlawing guns will stop people from being shot just as effectively as outlawing marijuana has stopped people from getting stoned. Seriously, anybody with decent metalworking tools and a modicum of experience working with them can make modern firearms in his choice of semiautomatic or automatic in his garage. Even if you managed to confiscate every gun currently in civilian hands with the wave of a wand and magically made it impossible to smuggle firearms across the borders of the U.S., cottage industry will replace them.

Second, the Constitution isn't going to get amended. Only 14 states need one house of legislature to say "no", and the Second Amendment stays in. There's no fucking way that people in favor of gun control are going to win a majority in both houses of the state legislatures in Texas, Mississippi, Alabama, Georgia, Florida, Tennessee, Kentucky, Arkansas, South Carolina, North Carolina, Wyoming, Utah, Montana, and Idaho in 2008. You're a moron if you think so.

Third, there is a damn thing they can do about it; refuse to comply. You think the army has a hard time enforcing order in Iraq? And that's assuming the soldiers don't mutiny against their orders; since soldiers are disproportionately Southern white males, that's not something you can take for granted.

Guns are here to stay. And there isn't a damn thing you can do about it.

It can happen (0)

Anonymous Coward | more than 7 years ago | (#18763429)

The 16th amendment was NOT passed and if it was it doesn't grant the power of general fund income taxes. We have both today and its forced upon us without any logic or law to back it up.

They can kill the 2nd if they want and if people just keep smoking their pot and smoking each other (with guns) without changing the government it will become the norm in 1 generation. At which point you can expect a "war on guns" type effort to remove the guns since they would then be against the law. Perhaps in 1 more generation people would believe the 2nd was actually repealed or only applies to new guns (in which case it would take forever to remove the old ones.)

If you resist- they can use all that homeland security toys they bought many of which were more about crowd control/torture than about real security. National Guard can be taken over by Bush over. State rights are almost dead and the EU to some extent shows you what a weak federal system would work like (which I'm in favor of; despite the EU being somewhat corrupt and lacking in ways for citizens to directly affect it)

What we need most is the death penalty for exiting politicians who vote for war and the requirement that all "police actions" must be declared war after 90 days! The USA hasn't had a "war" in decades!! Politicians who really are patriotic would give their lives for our protection... not for oil. Why should they not be directly affected? Doing these 2 things would greatly reduce our problems worldwide and domestic. Other nations should consider it as well.

College-Age "Kids" are dying in Iraq every day on every side because of equally crazy people! VT is no big deal (and making it a big deal only encourages the next nut to go out in fame.) These college students died for nothing.
The US troops in Iraq are also dying for nothing. (Iraqis on the other hand are dying for something.)

Wake up!

Eugenia, is that you? (0)

Anonymous Coward | more than 7 years ago | (#18763633)

I thought I recognized your incoherent and meandering thoughts. Shouldn't you be waxing your 'stache and that mess you call a bush?

Re:Virginia (-1)

Anonymous Coward | more than 7 years ago | (#18763271)

I guess you think that no human was ever murdered until the gun was invented. You stupid fucker - take away the guns (an impossible proposition) and people will just go back to stabbing and crushing each other. Do you plan to ban absolutely everything that isn't pliable with rounded edges? BTW, do you think that criminals give a flying fuck about firearm bans? It's already illegal for felons to own guns, yet they still manage to steal them or purchase them on the black market. Strip firearms from law-abiding citizens and you will be left with an armed criminal element, a largely unarmed law-abiding element, and a huge black-market for firearms. If you can't see that that would be a disaster, then you really are as dumb as you sound. As far as 2008 is concerned, any candidate who utters the words "gun control" will be promptly buried. Didn't you read about what the NRA did to that numbnuts who wrote for "Outdoor Life" magazine who mouthed off about assault rifles? Within a week he'd lost all advertising support and was canned. McCain was wise to voice his support for gun ownership for law-abiding citizens immediately. So far, his opponents are a blow-dried blowhard ex trial lawyer, a dyke stuck in a marriage of political convenience to a serial adulterer whose accountant turned up dead at a very convenient time, and a well-groomed Muslim who likes to take liberties with his personal history. Once Hillary and Osama finish mauling each other, McCain will practically waltz into the White House. Better luck in 2012, sucker.

banning guns only guarantees you'll be helpless (0)

Anonymous Coward | more than 7 years ago | (#18763401)

http://www.claytoncramer.com/weblog/2007_04_15_arc hive.html#7549578930590179871 [claytoncramer.com]

I knew the "blame guns" crown would be out en masse today. Those things don't fire themselves, you know. And our entire legal system is built upon the foundation of holding people accountable for their actions. VA Tech already had a policy in place banning handguns on campus. It sure was effective, wasn't it asshole? Lawbreakers will be lawbreakers. Take your micromanaging worldview and shove it up your ass.

Re:banning guns only guarantees you'll be helpless (0)

Anonymous Coward | more than 7 years ago | (#18763801)

On January 20, 2009, a Democratic president and congressional majority will be ready to shove my micromanaging worldview up your ass.

:)

It's not like guns are that hard to acquire (0, Offtopic)

melted (227442) | more than 7 years ago | (#18763693)

It's not like guns are that hard to acquire in countries with gun control. They may be different kind of gun (a hunting rifle, fgzample), but you could kill people with it just as well even if you're not a criminal. And criminals will have any kind of gun they want.

One thing you can't do in such a country is defend yourself against someone with a gun. That someone can kick in your front door, shoot your entire family before your eyes and you'll just sit there and watch and there won't be a damn thing you'll be able to do. In the US the guy with a gun always considers a possibility there's another guy with a gun in there. And that's good. Also, public figures have to consider a possibility that there's a guy with a sniper rifle sitting on the roof. So you don't want to piss off your constituents too much around here.

Quite frankly, if dems oppose the second amendment, I'll vote against dems. I don't think republicans could put out anything worse than GWB even if they wanted to, so by definition they won't be much worse than Billary.

Re:It's not like guns are that hard to acquire (0)

Anonymous Coward | more than 7 years ago | (#18764881)

In the US the guy with a gun always considers a possibility there's another guy with a gun in there

Which is of course why the criminal decides to carry a gun in the first place.

Also, public figures have to consider a possibility that there's a guy with a sniper rifle sitting on the roof.

Are you a professional idiot or just an American?

Re:Virginia (1)

Proofof. Chaos (1067060) | more than 7 years ago | (#18765099)

Anyone who doesn't support gun control shares responsibility for this tragedy. Libertarians, Republicans- you have blood on your hands today, every single one of you.
OMG, really? I feel so ashamed! What a tragedy, Einstein was right. And its all my fault! I only wish I had a gun, so I could shoot myself.
dumbass

YAY! (0)

Anonymous Coward | more than 7 years ago | (#18762689)

So the UTexas Online Homework System will accept NASA's answers? Good.

Jokes, but no discussion (-1, Flamebait)

Anonymous Coward | more than 7 years ago | (#18762747)

cue the uneducated comments and the one or two exceptions to the rule! Let's face it. All you fuckers are good at is tooling with computers. But you get some overinflated senses of intellect from it. The truth is, however, that you are no more sophisticated than a car mechanic. That is why you are the butt of real scientists' and mathematicians' jokes.

The one percent factor... (1, Interesting)

creimer (824291) | more than 7 years ago | (#18762775)

Thomas Edison said that genius is 1% and perspiration is 99% [phrases.org.uk] . It's nice to see scientists proving him right.

Re:The one percent factor... (5, Funny)

RandomPrecision (911416) | more than 7 years ago | (#18762913)

While I don't believe Tesla actually said it, I've often seen him credited with the phrase "If only Mr. Edison would a bit smarter, he wouldn't need sweat so much."

Re:The one percent factor... (4, Funny)

Anne_Nonymous (313852) | more than 7 years ago | (#18762931)

>> genius is 1% and perspiration is 99%.

My sweaty Uncle Phil must have a 198 IQ.

Re:The one percent factor... (0)

Anonymous Coward | more than 7 years ago | (#18763781)

hahaha rofl lmao!

funny you mention that... (1)

Bananatree3 (872975) | more than 7 years ago | (#18762971)

Slashdot's quote machine at the bottom of the page just displayed (I kid you not!):

Genius is one percent inspiration and ninety-nine percent perspiration. -- Thomas Alva Edison

Actually... (5, Interesting)

Moraelin (679338) | more than 7 years ago | (#18764665)

Actually, considering that Edison is famous for:

- taking credit for his employees' inventions as if he personally and singlehandedly came up with them. (There are at least 28 inventors that Edison ripped off this way, including for example taking credit for inventing the motion picture camera. Actually, it was invented by W.K. Dickson.)

- patented stuff he didn't actually have yet, and/or wasn't even original

E.g., he applied for a lightbulb patent a full year before actually having a filament that was commercially viable: and Edison's, or shall we say, his teams, _only_ contribution there was a commercially viable filament. The light bulb as such had already been discovered, it just didn't last long enough to be worth buying. But wait, even the carbon filament wasn't new: Edison't patent application itself had come a whole 1 year after Joseph Swan had patented a working model in England (and was working at it since 1850, 28 years earlier). So basically it took Edison and his team two years to copycat someone else's invention and claim credit.

- bogus patents, e.g., a number of patents on ornamental designs

- using PR and bad science to win public support: see the "war of the currents", where Edison (who wanted to sell direct current) paid people to roam the country and conduct demonstrations of killing cats, dogs, and once even an elephant with alternating current. Just, you know, to show people that alternating current kills. (While supposedly his direct current at the same 110V doesn't. Yeah, right.) He's also the author of the electric chair, as part of the same campaign to prove that AC kills. The first execution had the guy pretty much fried alive over a time of more than a minute (he certainly was still alive and struggling after the first 17 second jolt), in a show that sickened spectators and was described by the New York Times as, "an awful spectacle, far worse than hanging." That's the kind of PR that served Edison's purposes.

- shafting the employees. E.g., Tesla was promised a (huge for that time) bonus of $50,000 if he succeeds in making an improvement to the DC generators. When he actually succeeded, Edison didn't pay him, and in fact told him, "When you become a full-fledged American you will appreciate an American joke." In fact, he even refused to at least give Tesla a raise.

- mis-treating his employees. They actually spread word of Edison's current mood, so they'd know to duck for cover if he's in a bad mood.

- speaking of Tesla, here's one thing he said about Edison's dumb trial-and-error methods, a.k.a., 99% perspiration: "His method was inefficient in the extreme, for an immense ground had to be covered to get anything at all unless blind chance intervened and, at first, I was almost a sorry witness of his doings, knowing that just a little theory and calculation would have saved him 90 percent of the labor. But he had a veritable contempt for book learning and mathematical knowledge, trusting himself entirely to his inventor's instinct and practical American sense." (Would explain why most "Edison" inventions were actually from employees who actually understood what they're doing.)

- various attempts at monopoly, including the infamous "Motion Picture Patents Company", a.k.a., the Edison Trust. You know, if you thought that MPAA is bad, the MPPC meant you couldn't even make independent films without Edison's blessing.

- showing more contempt to the artists than the RIAA today, and in fact, enough to make the RIAA look like the good guys. Edison refused to even print the artist's name on the label. You're buying Edison music, you peon, not some artist's music. On one occasion he stated, "I would rather quit the business than be a party to the boasting up of undeserved reputations." Yeah, who do you think you _are_ to be getting any reputation for your talent and popularity. Only the great Edison should get a reputation out of it.

- letting his personal moods and preferences be the only criterion, and showing total contempt for what the paying customer actually wanted to hear or see. Ultimately that was the downfall of both his music and film publishing.

- cult of personality. The marketting manuals, for example, emphasized trying to shift attention from the public's demand for certain artists or to know who the artist is, to the fact that "the Great Wizard" personally selects the voices worthy of being recorded. I kid you not. The Great Wizard. So basically, again, forget the artists, it's the great Edison who deserves the glory for it.

Etc. ...well, I'll say that PHBs everywhere prove him "right" every day. You don't have to wait for something like this :P

NOVA did episodes, helps visually (4, Informative)

priestx (822223) | more than 7 years ago | (#18762795)

I spent a week watching all the Nova PBS episodes, learning about this and string theory. Even though I'm not a mathematician or physicist, it certainly caught my attention.

http://www.pbs.org/wgbh/nova/elegant/ [pbs.org]

Re:NOVA did episodes, helps visually (1)

Democritus the Minor (762206) | more than 7 years ago | (#18764341)

too bad string theory is about as plausible as religion... yeah, i'll take the flamebait mod. string theory isn't all that elegant.

Re:NOVA did episodes, helps visually (2, Insightful)

Proofof. Chaos (1067060) | more than 7 years ago | (#18765355)

No, string theory is about as plausible as epicycles http://en.wikipedia.org/wiki/Epicycles [wikipedia.org] . Just keep adding dimensions (instead if circles), and you can make it match results.

I'll hazard three guesses. (0, Troll)

jd (1658) | more than 7 years ago | (#18762865)

Firstly, I'm going to guess that frame dragging is verified at no better resolution than the curvature of space/time, but that as far as they can tell, it exists and meets the values expected by Einstein.

Secondly, I'm also going to guess that QM experts will start to get a little nervous. The properties any future QM model of gravity must have contradict the GR model. They cannot both be right. The more "right" the GR model, the more problematic a QM model. This doesn't mean a QM model does not exist, only that it is most undesirable (from a QM perspective) for the GR model to make highly precise and accurate predictions.

Thirdly, frame-dragging occurs at a non-zero distance from an object. This doesn't matter, for the purpose of these observations, as they're nowhere near accurate to measure the relativistic effects that apply to the information passed that creates the effects in the first place. Nonetheless, such an affect must exist, or you'd end up with infinitely fast rates of change of state, which is expressly forbidden in GR. It's a gross simplification and it's not an "obvious" conclusion to reach by any means, but if the curvature (and restoration) of space/time has nothing analogous to Hooke's Constant, then after a gravitationally massive object has moved, either space/time would not unbend at all (it could only do so if Plato's laws of motion were valid), or every moving object would need to be emitting Hawking Radiation (which - as far as anyone knows - doesn't happen).

Re:I'll hazard three guesses. (3, Funny)

pipingguy (566974) | more than 7 years ago | (#18762939)

Let me see if I understand you: is this similar to the mall thing where you throw coins into it and they go round-and-round until disappearing into the hole below? If it is, then...I...waitaminit...we're all going to die!

Re:I'll hazard three guesses. (0)

Anonymous Coward | more than 7 years ago | (#18763021)

The other night I told my kid "Someday, you'll have children of your own." He said "So will you."

Dude, he just called himself a bastard.

Mod parent down. (0)

Anonymous Coward | more than 7 years ago | (#18763035)

Technobabble

Re:I'll hazard three guesses. (0)

Anonymous Coward | more than 7 years ago | (#18763051)

Firstly, I'm going to guess that frame dragging is verified at no better resolution than the curvature of space/time...either space/time would not unbend at all (it could only do so if Plato's laws of motion were valid), or every moving object would need to be emitting Hawking Radiation (which - as far as anyone knows - doesn't happen).
Great post, I think. Such concepts still allude me. Even the depth of my understanding about string theory is "from a kite? or where I slip my dollar bill?". Therefore, I can only assume you make a mighty fine point here and agree fully with it. Btw, Hawking Radiation? Just slap some duct tape around the edges of his leaky 12V chair battery. Wouldn't that fix it?

Re:I'll hazard three guesses. (1)

QuantumG (50515) | more than 7 years ago | (#18763297)

It's worse than that. If GR is right and not just the observable result of some underlying process then we live in a block universe. That not only means that QM is wrong, it means we have no free will.

I like what you have to say about every moving object emitting Hawking radiation.. kinda reminds me of Mach's Principle [wikipedia.org] . Perhaps every object in the universe emits particles in sympathy to a moving object.

Doesn't make much difference to its status (2, Funny)

anandsr (148302) | more than 7 years ago | (#18763399)

The thing is that this effect has been tested at strong gravity. There is no dispute that GR is not correct in the strong gravity limit. The strength of GR is only disputed at weak gravity, or near Planck's length. It is a good verification of GR, but I don't think anybody thought that it will not be vindicated.

We need a probe to test GR at L1 point if the gravity there is significantly weaker than a0 to distinguish between MOND and DM. This IMHO is the most important test. If it is not possible to test MOND at L1 point, because the MONDian bubble is too small then there is no hope for a test within the next decade. Because that is how much time a very modern satellite will take to reach beyond the solar system where the gravity is significantly weaker than a0.

Re:Doesn't make much difference to its status (1)

Bramantip (1054582) | more than 7 years ago | (#18764777)

Wow. That post has a pretty dense nonsense to acronym ratio. Asymptotic to 1.0 - Congrats!

Funny? (1)

Proofof. Chaos (1067060) | more than 7 years ago | (#18765421)

WTF?

Re:I'll hazard three guesses. (5, Interesting)

LionMan (18384) | more than 7 years ago | (#18763577)

It distresses me a little to see a post modded so highly just because it throws together the right words; but I suppose that says something about me as well, given my choice of forum. Anyway, since I nominally study gravitation, I feel like I should clarify some things in a reply.

Firstly, I'm going to guess that frame dragging is verified at no better resolution than the curvature of space/time, but that as far as they can tell, it exists and meets the values expected by Einstein.
Frame dragging is the name of one particular way in which spacetime curves. It is curvature. To say something about frame dragging or curvature is to say something about the other. I don't know if the parent statement makes sense or not. The group has not released their frame dragging measurements yet, just the geodetic precession measurements (the precision of which will likely go up as they isolate more systematics in their data as they move toward making a statement about frame dragging). Frame dragging is about 100 times harder to measure than geodetic precession, for the mass and spin of the Earth.

Secondly, I'm also going to guess that QM experts will start to get a little nervous. The properties any future QM model of gravity must have contradict the GR model. They cannot both be right. The more "right" the GR model, the more problematic a QM model. This doesn't mean a QM model does not exist, only that it is most undesirable (from a QM perspective) for the GR model to make highly precise and accurate predictions.
GR is arguably the most successful physical theory to date (I would say that electrodynamics rivals it since it has been formulated classically in curved spacetime and also has been quantized successfully in flat spacetime, but that is another discussion). Newton was not "right", but note that GR simplifies to Newtonian mechanics in the weak field and non-relativistic limit. Any theory which supersedes a highly successful physical theory must reproduce said theory in the proper limits. A quantum theory of gravity must reproduce GR in the macroscopic limit, just as quantum mechanics has a correspondence principle which allows it to reproduce classical wave and particle phenomena in the appropriate limit. I don't think any physicist is nervous about these results - everybody expects GPB to verify the predicted frame dragging. Deviations from the values predicted would excite fans of MoND, SVT theories, and other alternative theories of gravity.

Thirdly, frame-dragging occurs at a non-zero distance from an object.
Frame dragging curves spacetime globally, but falls off to asymptotic flatness. The parent statement probably makes sense.

This doesn't matter, for the purpose of these observations, as they're nowhere near accurate to measure the relativistic effects that apply to the information passed that creates the effects in the first place. Nonetheless, such an affect must exist, or you'd end up with infinitely fast rates of change of state, which is expressly forbidden in GR.
The NSF and NASA don't spend this much money to throw an instrument into space unless they think it will actually measure what it's supposed to. The gyros are the most spherical macroscopic manmade objects, which used superconducting quantum interference devices (SQUIDs) to precisely measure their precession, blah blah blah, read about it on their web site. I sure hope they're accurate enough to measure those relativistic effects, because that's exactly what they've been designed to do. I don't know what information you are talking about. The Einstein Field Equations are local, so there is an inherent limit on the speed at which 'information' (curvature) propogates through spacetime.

It's a gross simplification and it's not an "obvious" conclusion to reach by any means, but if the curvature (and restoration) of space/time has nothing analogous to Hooke's Constant, then after a gravitationally massive object has moved, either space/time would not unbend at all (it could only do so if Plato's laws of motion were valid), or every moving object would need to be emitting Hawking Radiation (which - as far as anyone knows - doesn't happen).
I don't think that the parent statement is sensical. Spacetime is dynamical and certainly responds to the motion of energy (one form of which is mass density). You are feeling it right now in what seems to be a static frame as we are accellerated away from free-fall trajectories standing on the surface of the Earth. In this frame, we also see a dynamical curvature due to the relatively slow motion of the Moon about the Earth. Those tides 'following' the moon should be enough to convince you that spacetime is curving in response to the motion of energy. I guess you could call it Hookian if you really felt like it. I won't stop you. I'll call it the Einstein Field Equations. I have no clue as to why you've brought Hawking radiation into this. Hawking radiation is only non-negligeble in the regime where both quantum and general relativistic effects are important - where the length scales of curvature are comparable to the quantum scales (if you want a single number, go with the Planck length). Anyway, the experiment has nothing to do with that regime. I'm going to sleep.

MOD UP (0)

Anonymous Coward | more than 7 years ago | (#18764021)

totally owned the gp.. i think..

Re:I'll hazard three guesses. (1)

jmp (84073) | more than 7 years ago | (#18764089)

It distresses me a little to see a post modded so highly just because it throws together the right words
Thanks Leo. Even to a non-physicist like me, JD's post smelled like bullshit and buzzwords. Good to see a well-written response that at least seems to make sense. :^)

MOND approximates to GR in strong field. (3, Informative)

anandsr (148302) | more than 7 years ago | (#18764199)

This means that there are no differences between GR and MOND in the gravitational limit that this test has been conducted. This means that MOND will have the same problem that GR has, if the tests don't come out as predicted. I guess in this case the tests will be considered to be faulty, as there are literally no theories (that are not considered crackpot) that give different results different from GR in the strong field regime. So the tests by Gravity Probe B will not make any difference, though it probably will give GR theorists something more to brag about.

There is a big misconception about MOND, that it is a theory. It is not, it is a law that works very well at the Galactic Level and somewhat at the cluster level. MOND fits all galactic level data to the limit of their expected accuracy. This it does so with a single universal constant. But nobody knows why it works so well.

As such it is very obvious there is something behind MOND. GR cannot explain MOND without fine tuning DM in such a way to give rise to MOND. But since MOND uses only Baryonic matter, it leaves DM with no degrees of freedom, which is not possible, so DM must not exist at the Galactic level.

At Cluster level situation is different MOND does not match up with the missing mass. Which means either there is Dark Matter at the Cluster level or MOND itself is a reasonable approximation of the correct theory of gravity only in the galactic limit. Beyond the galactic level it ceases to be a good approximation.

If there is dark matter at the cluster level then there must be a reason why it does not exhibit itself at galactic levels. This would meant that the dark matter is hot and moving at a high velocity, which allows it to form stable structure only at the cluster scales.

The interesting thing about the universal constant (a0) of MOND, is that if a particle is accelerated by a0 for the whole life of universe then we will get the speed of light. This would seem to provide a hint that a0 is due to the curvature of the universe.

This actually solves a problem in GR. If GR is absolutely correct then the curvature of the universe cannot be determined, which is also called the flatness problem. This problem is currently avoided by assuming that there was an inflationary era when the universe expanded so much that we only see a very small part of the universe which is flat. So that GR equations are correct. But if that is not true and the universe is not really that big then GR will break down because of no fault of itself, but simply because of the curvature of the universe.

So in my opinion GR is correct but the curvature modifies GR in such a way that we observe MOND.

Re:I'll hazard three guesses. (1)

Proofof. Chaos (1067060) | more than 7 years ago | (#18765385)

Who moded this person a troll, without posting a response? Everything they said went about a mile over my head, and I consider myself somewhat informed about this subject. Just because you don't understand the post, doesn't make it a troll.

Spinning Weights (3, Insightful)

Doc Ruby (173196) | more than 7 years ago | (#18762871)

If I put three gyroscopes, each spinning in a different axis at right angles to each other, into a box, wouldn't its increased inertia make it just seem more massive? How does the momentum of all those electrons and other subatomic particles spinning around contribute to its apparent mass?

Re:Spinning Weights (4, Informative)

slazar (527381) | more than 7 years ago | (#18763307)

Gyroscopes resist changes in angular momentum, not linear momentum. So it only has increased rotational intertia. If you were measuring the box's mass by trying to spin it rather than push it, then yes, it would appear more massive. But if you just pushed it in a straight line, then it would behave the same as if your gyroscopes were still.

On your second question, electrons and subatomic particles don't really spin, they have orbitals. Electron orbitals are the probability distribution of an electron in a atom or molecule. Take a look: http://www.orbitals.com/orb/ [orbitals.com] So it's not really like a gyroscope. But that is an interesting question, i.e. Do electron orbits effect the angular momentum of atoms? How would you measure that experimentally? Does Newtonian Physics operate on that level?

Re:Spinning Weights (1)

evanbd (210358) | more than 7 years ago | (#18763959)

Actually, you missed on both counts.

Putting more than one gyro in a box is the same as putting one in with a different angular momentum. Angular momentum is a vector quantity; two gyros add together and act like one with the corresponding angular momentum. So when you try to move the box it will act like a box with a gyro in it, and you won't be able to tell how many gyros there are.

Electrons orbit in orbitals, but they also spin, like how the Earth both orbits and rotates. See Quantum spin [wikipedia.org] for details. Electrons and other subatomic particles have angular momentum. But, since for the most part they're randomly aligned, you don't notice -- as above, the spins add to mostly zero. I believe there are macroscopic experiments that demonstrate this, but I don't remember details off hand.

Re:Spinning Weights (1)

moosesocks (264553) | more than 7 years ago | (#18764103)

Quantum spin is one of those things [xkcd.com] you just have to accept in Physics without asking too many questions. (because if you don't understand Quantum Spin yet, you probably won't understand the answers to those questions --- Physics is fun like that)

Particles have angular momentum, even though they're not necessarily rotating in the classical sense of the word (as a wheel does). Confusing? Yes. Useful? HELL YES. For one, MRI imaging relies entirely on quantum spin to work.

Re:Spinning Weights (2)

imsabbel (611519) | more than 7 years ago | (#18764397)

Well, if electron orbits didnt affect angular momentums, we wouldnt have spin-orbit coupling in quantum mechanics, would we?
Of course your orbital carries an angular momentum (i.e. the electron "spins around the core") if l>0, i.e. for most electrons. Its just very small.

Re:Spinning Weights (1)

DirtySouthAfrican (984664) | more than 7 years ago | (#18763695)

Yes, since the constituents of the object have more kinetic energy. In the same way that a hot potato weighs more than a cold potato. Relativistically speaking, the total "apparent" (energy, momentum) 4-vector of the object is equal to the sum of the 4-vectors of the individual particles, so while the momentum can add up to zero, the energy component of the 4-vector is increased. From there, E^2 = m^2* tells you that energy ~ mass. In your example of the atom or subatomic particle, you also have to take into account the contribution of the binding energy (potential energy), which actually has the opposite effect, making atoms lighter.

* God-given units.

Re:Spinning Weights (2, Informative)

Have Brain Will Rent (1031664) | more than 7 years ago | (#18764849)

This isn't quite what you are asking but most of the mass of an atom comes from the motion of the constituents of the protons and neutrons. In other words most (80%-90% IIRC) of what we perceive as the rest mass of an atom is actually not rest mass at all but relativistic mass attributable to the motion of quarks.

This was a stanford experiment (4, Informative)

scubamage (727538) | more than 7 years ago | (#18762887)

This was not a NASA experiment per se, it was a Stanford experiment. The original press release can be found here [stanford.edu] . The official stanford website also lists preliminary findings here [stanford.edu] .

Re:This was a stanford experiment (1)

mbone (558574) | more than 7 years ago | (#18765233)

Uh, no, it was a NASA experiement. They funded it. Lots of people from all over worked on it - the CFA (Harvard) group was essential to its success, for example.

How very sad (0, Redundant)

psaunders (1069392) | more than 7 years ago | (#18762999)

and tragic, that Albert Einstein could not have lived long enough to see this glorious day.

Of course, he was already dead when the project started...

Re:How very sad (1)

i kan reed (749298) | more than 7 years ago | (#18763535)

Jeez, 19551960, it doesn't take Einstein to figure that one out.

links (4, Informative)

SaberTaylor (150915) | more than 7 years ago | (#18763067)

sciency details:
http://cosmicvariance.com/2007/04/15/dragging-on/ [cosmicvariance.com] (4:33 p.m.)

Also of interest if you're into this sort of thing, what Beyond Einstein programs will be cut?
http://scienceblogs.com/catdynamics/2007/04/beyond _einstein_iv_showdown_in.php [scienceblogs.com] (April 4)
sad if you compare sticker prices to the $10 billion per month on the Iraq adventure.

The most interesting thing to me is apathy (4, Interesting)

zappepcs (820751) | more than 7 years ago | (#18763069)

with regard to this. This isn't someone claiming ID causes the universe to act as it does, this is FSCKING Einstein. That he is proved correct is more about man understanding the universe, and relying less on the theory that it is too complicated to understand and must have been created by an imaginary being. This *IS* news, and should be heralded appropriately.

While some might think me a troll, think about it, Einstein was right. That means that we are that much closer to understanding how the universe works. Even 100 years ago such progression could only be imagined, not proven. In the time that we live in, science books have to be revised every year not because of a need to spend government money, but to actually keep them up to date!

So much change and investigation. People have become numb to the actual changes.

Re:The most interesting thing to me is apathy (0)

Anonymous Coward | more than 7 years ago | (#18763193)

Not sure how science disproves god, or vice versa. Not all religion's think that technology is evil/pointless.

Re:The most interesting thing to me is apathy (4, Interesting)

zappepcs (820751) | more than 7 years ago | (#18763363)

My friend, don't be fooled. One step closer to understanding how the universe works is one step closer to proving that irreducible complexity is as mythical as the flat earth, the perfect sun, or that the earth is the center of the universe.

Not all religions think that technology is evil/pointless, but the ones that are most dangerous do. This doesn't disprove the existence of god, or prove it. It disproves irreducible complexity, and thus the theory of intelligent design. ID is that theory that would not explore or experiment because it cannot be understood, things just are because god created them that way. Evolution didn't happen, the big bang didn't happen... all that claptrap. god may well exist, and may well have caused the big bang, or the chain of evolution to begin... who knows. The point is that understanding how things work is important to us as a species. Those that would oppose such investigations and the evidence they produce are dangerous to all of us. Scientists are heroes. Not even 1000 years ago men were killed or imprisoned for knowing less than we take for granted as common knowledge today.

Re:The most interesting thing to me is apathy (1)

Debug0x2a (1015001) | more than 7 years ago | (#18763715)

Not only that, we have now succeeded in creating an experiment to prove a theory that has these implications. Not only does this close many questions pertaining to it, it also shows that we have developed more methods of experimentation that will hopefully allow us to probe farther into the questions of relativity. I think the new questions this allows scientists to ask are more important then the proof itself.

Re:The most interesting thing to me is apathy (1)

Tickletaint (1088359) | more than 7 years ago | (#18763947)

Arrgh. Not to argue with your overall sentiment, but I don't know how helpful it is to state categorically that this "proves Einstein correct." All the experiment shows, indeed all any experiment can show, is that his model turns out to be useful in predicting events in the world as we understand it. It's like saying Galileo's drop tower experiment would have "proved" Newton's laws correct—true enough for its time, but with the benefit of more accurate measurements and a broader philosophical inquisition, not nearly the complete picture as we know it today.

Re:The most interesting thing to me is apathy (1)

Logic and Reason (952833) | more than 7 years ago | (#18764567)

I think the apathy in this case is due more to the fact that pretty much everyone expected this result.

I knew it! (0)

Archangel Michael (180766) | more than 7 years ago | (#18763239)

Gravity is such a Drag.

Re:I knew it! (1)

camperdave (969942) | more than 7 years ago | (#18763601)

Oh for the good old days when Gravity was a Downer, Friction was a Drag, and physics could be understood without needing about three lifetimes worth of math degrees.

Smart (0)

kahrytan (913147) | more than 7 years ago | (#18763403)

See, Einstein was a genius. Yet, He struggled with Math. He is my hero.
 

Re:Smart (0)

Anonymous Coward | more than 7 years ago | (#18763495)

yeah when he was like 8... by the time he was 13 he could run rings around college students

Einstein never struggled with maths (0)

Anonymous Coward | more than 7 years ago | (#18764927)

They changed the marking system from best to worst to worst to best and journalists from later years never realised that his seeming failures to pass at maths were in fact distinguished passes.

Einstein struggled with people rather than maths, he just never did people well, which I suppose is why his son died impoverished, insane and in Switzerland (hard to know which is the worst option).

From TFA: (1)

l0cust (992700) | more than 7 years ago | (#18763417)

But Lisa should help scientists understand how the theory works in "high field" gravitational regimes such as pairs of massive black holes.
I think she will definitely be able to do that if she has a tattoo on her lower back. Just saying..

Wish I had mod points. (1)

Donniedarkness (895066) | more than 7 years ago | (#18765387)

This is funny, and not just because the only person I know with a tattoo on her lower back is an ex of mine.

The complexity of Einstein (0)

Anonymous Coward | more than 7 years ago | (#18763527)

So, did Einstein turn out to be an NP-complete problem?

More info (4, Informative)

onx (956508) | more than 7 years ago | (#18763929)

For some reason the article and summary only mention that Gravity Probe B was trying to measure was "minuscule" however, I at least find the actual quantity to be FAR more impressive than some journalist calling it small. Anyway want to know the precession?

Frame Dragging Effect (has NEVER before been measured): 1.1x10^-5 degrees per YEAR
Geodetic Effect: 1.8x10^-3 degrees per YEAR

Clearly then, these were not merely "minuscule" shifts...the potential for error is great.

More information can be found at http://www.nasa.gov/mission_pages/gpb/index.html [nasa.gov]

Cascading Effects? (0)

Anonymous Coward | more than 7 years ago | (#18764017)

Could a physicist elaborate as to whether or not this affects the alternative theories of gravity, such as MOND?

Moving back in time (0)

Anonymous Coward | more than 7 years ago | (#18764247)

> In a similar way, the Earth drags local space and time around with it -- ever so slightly
> -- as it rotates. Over time, these effects cause the angle of spin of the satellite's
> gyroscopes to shift by tiny amounts."

Sweet, so that whole superman flying around the Earth so fast to make it spin backwards so that time will reverse itself is real. That's awesome.

No, no, no. I don't need a scientific affirmation that this is how it works. It's simply awesome. Awesome.

oops (5, Insightful)

Tom Womack (8005) | more than 7 years ago | (#18765123)

Basically, the mission hasn't yet succeeded, and it doesn't seem to be completely certain that it will.

The goal was to measure the frame-dragging effect of the Earth, which is of the order of 40 milli-arcseconds per year; the current calibration (http://einstein.stanford.edu/content/aps_posters/ ExperimentError.pdf) has a one-sigma error of 100 milli-arcseconds per year, significantly larger than the relativistic effect and significantly larger than the effect from the motion of the target star through space. The initial expectation was for an error budget of less than 0.5 mas per year, so there was a lot of work done on measuring the proper motion of the star to that precision.

The problems turn out to be really crazily subtle issues in solid-state physics -- the deposited metal films on the gyroscope and on its housing retain charge in patches large enough that they have to be modelled rather than averaged out -- plus an annoying issue from classical mechanics where the motion of a rigid body around three axes XYZ depends on the ratio of the differences of the moments of inertia X-Z and Y-Z. Whilst the gyroscopes are absurdly precisely made, so the moments of inertia are very close, the ratio of the differences of the moments of inertia is a macroscopic number; this is the same effect, and even a similar cause, to some of the oddities with low-precision floating-point arithmetic.

They'll probably be sorted out, sigma might be reduced by a factor ten after another year's modelling effort, but it seems unlikely that they'll get it down by the factor 200 they were hoping for.

The frame-dragging has already been measured indirectly by looking at the flickers of X-ray sources caused by frame-dragging-induced precession of the accretion discs around black holes, and most of the theories that suggest relativity is wrong would suggest that any oddities would be more pronounced in the huge gravitomagnetic fields near black holes than in the tiny fields near a mass as small, as non-dense and as slowly rotating as Earth.

1% is a lot (0, Troll)

mveloso (325617) | more than 7 years ago | (#18765291)

Validated to 1% isn't validated at all.

If my solution is only 99% correct and it's used by billions of people, well, that's not very good. It's mostly good, but that's hardly validation.

Re:1% is a lot (1)

Ox0065 (1085977) | more than 7 years ago | (#18765429)

cough...
The test results have a significant margin of error... ...hence being within 1% of the predicted results, indicates the predictions made decades earlier were probably pretty spot on!

cough...
ie. 1% probably in test results (which someone up the screen noted are not yet fully processed) rather than in the theory...
Worth considering before throwing out a theory that matches test results to within 1%, wouldn't you say?

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