NASA Gravity Probe Confirms Two Einstein Predictions 139
sanzibar writes "After 52 years of conceiving, testing and waiting, marked by scientific advances and disappointments, one of Stanford's and NASA's longest-running projects comes to a close with a greater understanding of the universe. Stanford and NASA researchers have confirmed two predictions of Albert Einstein's general theory of relativity, concluding one of the space agency's longest-running projects. Known as Gravity Probe B, the experiment used four ultra-precise gyroscopes housed in a satellite to measure two aspects of Einstein's theory about gravity. The first is the geodetic effect, or the warping of space and time around a gravitational body. The second is frame-dragging, which is the amount a spinning object pulls space and time with it as it rotates."
I'm tired of Matt Welsh (Score:5, Insightful)
Please, can somebody restore the fortune database? Thanks.
Uh, and First Post.
Re: (Score:1, Offtopic)
Re:I'm tired of Matt Welsh (Score:5, Informative)
The new Slashdot: too buggy to be fit for purpose.
I have to agree with this, several bugs. The most annoying one is having the comments scroll to the top of the page when I click anything.
Re: (Score:2)
Re: (Score:1)
I don't have this problem. It's probably Opera's fault though. For some months I've been wanting to try Firefox/IE9/Chromium because Opera has many unfixed bugs that go back even to version 9. For example, I can't select any text in this text box without doing a right click>select all first. I reported this to them 4 years ago.
Re:I'm tired of Matt Welsh (Score:4, Insightful)
I have to agree with this, several bugs. The most annoying one is having the comments scroll to the top of the page when I click anything.
Links are now unclickable, at least on the first 4 or 5 tries. Each time you click a link in someone's post, the page jumps and/or another post expands/collapses. The sheer level of ignorance and/or lack of interest in their own site on the part of the Slashdot owners is mind-boggling.
(Click on links? I must be new here.)
Seriously, Slashdot, fix your goddam site.
Re: (Score:2)
Re: (Score:2)
Re: (Score:3)
Um, maybe the developer uses a Droid X for development work.
That would explain quite a lot actually...
Re: (Score:2)
And here I thought it was just my fault for not using IE...
Re: (Score:3)
Mark slashdot.org as untrusted.
Switch to classic discussion mode in your preferences.
Re: (Score:2)
Couldn't agree more.
EVERYTIME /. upgrades the first thing I do is go back and turn classic discussion mode back on.
Re: (Score:1)
Re: (Score:2)
no, but I can link to the related saturday morning breakfast cereal comic.
This is why experimental scientists hare theoretical scientists [smbc-comics.com]
Re:I'm tired of Matt Welsh (Score:5, Funny)
Please, can somebody restore the fortune database? Thanks.
Uh, and First Post.
Restore it? It works fine for me, here:
Are Linux users lemmings collectively jumping off of the cliff of reliable, well-engineered commercial software?
In fact, I've been seeing that for a few days!
Protip: Say that quote while walking the halls. You will immediately know who your fellow /.ers are by the snickers. If your boss laughs, then you're in trouble.
Re: (Score:2)
Are Linux users lemmings collectively jumping off of the cliff of reliable, well-engineered commercial software?
Protip: Say that quote while walking the halls. You will immediately know who your fellow /.ers are by the snickers. If your boss laughs, then you're in trouble.
Well, I'd laugh at that quote -- specifically, the presumptions it implies.
Re: (Score:1)
Honey? (Score:4, Funny)
"Imagine the Earth as if it were immersed in honey," Francis Everitt, GP-B principal investigator at Stanford University in Palo Alto, Calif., said in a statement
Doh, this is Slashdot, we want a car analogy, please. And have the numerical results expressed in libraries of congress per football field. Thanks.
Re: (Score:1)
Re: (Score:1)
Re: (Score:2)
Re: (Score:2)
"Imagine the Earth as if it were immersed in honey,"
I thought that we were already immersed in honey . . .
I'm not sure where that comment should go . . . tip the veal, try the waitress . . .
Re: (Score:2)
I tried imagining the whole Earth as if it were immersed in honey, but I could never get past imagining Brooklyn Decker [google.com] immersed in honey.
Re: (Score:1)
Re: (Score:1)
Lets call this honey aether
Re: (Score:1)
Re: (Score:3)
"we want a car analogy"
Imagine a Dodge Daytona Charger as if it immersed in STP...
Re: (Score:1)
I use soccer fields you insensitive clod!
Re: (Score:2)
Okay, then... Imagine a car as if it were immersed in honey.
Perhaps a compromise? (Score:2)
Imagine Natalie Portman, as if she were immersed in hot grits...
Re: (Score:2)
Re: (Score:2)
Nasa Warp Drive Project (Score:1)
Re:Nasa Warp Drive Project (Score:4, Funny)
Re: (Score:1)
Re: (Score:2)
http://www.grc.nasa.gov/WWW/bpp/ [nasa.gov]
They stopped it in 2002, it was basically throwing relatively small amounts of money at some ideas and seeing if anything stuck...
NASA and the USA (Score:5, Insightful)
I am not an American, but I have seen both the blue pearl image and the pale blue dot image. I have read about how long these projects have run and the astounding quality of the instruments that must be on satellites like these along with the massive foresight it must have taken at launch time to make them relevant decades later. You can criticize the USA all you want for their wars, and I have heard some harsh criticism of NASA too but the most astounding images and discoveries have always come from the here because they are on the pinnacle of space exploration. The world would be a lot less interesting if it wasn't for them.
Re: (Score:2)
Not exclusively USA
Some 100 students achieved their PhDs by working on some aspect of the mission during the many years it took to develop, build and then fly the probe. Most of these PhDs were earned at Stanford, and at the universities in Huntsville; and in Aberdeen, UK. More than 350 undergraduate students also worked on GP-B, including one who later became the first female American astronaut in space, Sally Ride. Another was Eric Cornell, who won the Nobel Prize in Physics in 2001. [bbc.co.uk]
Re: (Score:2)
the massive foresight it must have taken at launch time to make them relevant decades later,
The satellite we're talking about here was launched in 2004. The project ran for much longer, that time was spent developing the technology. FTFA:
Decades of research and testing led to groundbreaking technologies to control environmental disturbances that could affect the spacecraft, such as aerodynamic drag, magnetic fields and thermal variations. Furthermore, the mission's star tracker and gyroscopes were the most precise ever designed and produced.
Very impressive research, yes. 'Massive foresight', not so much.
Re: (Score:1)
This was more of a comment on NASA and the US and not on this particular satellite mission. What I actually was thinking of when i wrote it was the voyager craft.
Re: (Score:2)
Re: (Score:2)
Whoa there. There was no bashing going on in my comment.
GP said "...the massive foresight it must have taken at launch time to make them relevant decades later". I thought GP was referring to Gravity Probe B. GP was launched 7 years ago, not decades. Its equipment was developed specifically for this mission. Development took a long time, but the ultimate goal was always clear, in other words Gravity Probe B's results are due to proper planning. Not 'foresight'.
Foresight is defined as "The ability to predict
David de Hilster (Score:1)
Have you seen the comments in TFA by this David de Hilster guy? What a fruitloop. Check out his picture [newiki.org]. Want some love particles, baby?
Mission update page is outdated, but (Score:5, Informative)
Re: (Score:2)
Re: (Score:2)
Observer effect - did it mention this? (Score:1)
Re:Observer effect - did it mention this? (Score:5, Interesting)
Re: (Score:3)
Now, there's been a huge amount of speculation as to how the two combine, especially from theoretical physicists like Dr. Hawking. However, there have been absolutely no experiments in quantum gravity, for one simple reason: the only time you get that much
Re: (Score:2)
1.61lb is considerably less than a yottagram. Cavendish Experiment [wikipedia.org]
Re: (Score:2)
Re: (Score:2)
The effects of gravity are at macro scales, not quantum scales.
The effects are on all scales. Just because nobody can currently describe how a single photon warps space as it travels does not mean it does not occur. We know it does.
Re:Observer effect - did it mention this? (Score:5, Informative)
t (basically ALL experience is subjective to the observer - even scientific ones...)
That's not part of quantum mechanics at all. That's a gross generalization made philosophical that arose out of an actual quantum mechanical principle.
Measurement-related QM principles, like wavefunction collapse and Heisenburg, are only meaningful when what you're observing is the size and scale of a quantum state, which is very, very small. Gravitational effects are for the most part (and in this case) for large objects, where QM principles are unimportant.
Re: (Score:2)
Re: (Score:3)
It depends on your perspective. It's "relativity" because most measurements you make *are* relative to your reference frame, only the speed of light (and various invariant quantities) are absolute.
The relativity that SR and GR deal with is different in kind than the "peculiarities" of quantum mechanics. And, the previous post was correct: the observation-related uncertainties of QM are (mostly) only important when systems get to microscopic scales. Yes, the same microscopic laws apply to macroscopic phys
Re: (Score:2)
Only observers in inertial reference frames agree on the laws of physics, no?
Re:Observer effect - did it mention this? (Score:4, Informative)
You need to actually study quantum physics if you want to talk about these things like an adult. It's obvious to everyone that HAS studied quantum physics that you're spouting nonsense and claiming that Science supports you. Quit watching "What the bleep do we know?". It's full of people lying to you to sell you an idea (and one scientist who was duped and every single quote taken out of context).
Re: (Score:2)
The observer effect is not something specific to self-aware observers. It can simply be interaction with other matter - which has then "observed" the item in question.
Now with that out of the way, what you want to happen has no influence on what does happen. That's simply not what the observer effect is about.
Re: (Score:2)
That should really be a law.
Re: (Score:2)
But if you're just arguing solipsism for your "we're all in the matrix" kicks, then man, don't bother. We're not really even here anyway.
well... (Score:2)
I usually bow out of stories like this, but must make one comment:
Anybody who thinks time is important as a metric is seriously missing the point.
We will talk about it... (Score:1)
Sometimes we to just shut up and do it else we'll have deja vu like solar energy [wikipedia.org] or nuclear power [world-nuclear.org]
Re: (Score:2)
Re: (Score:1)
Oh, and thank you, Dr. Einstein, for thinking about this stuff and putting it in a form that could be challenged experimentally.
Re: (Score:1)
Denial (Score:1)
Finally I can put an end to all of those naysayers of gravitation theory!
Re: (Score:2)
Look - it's just at THEORY - you admitted it yourself right in your post. Go find some facts and get back with me. I've got a Bible full of them right here at my desk, and there isn't a single mention of gravity. I can't believe you're still blathering on about this... ;-)
Re: (Score:2)
Blah, I Hate This! (Score:4, Funny)
Re: (Score:3)
In the beginning, Bob created the heavens and the earth. But his emulation of Newtonian physics was but partially implemented, and so he only got a B-.
Re: (Score:2)
Dear Mr. 94343,
I would like to thank you for considering our ilustrious instituion. I regret to inform you, however,
that you have not been accepted to our "Universe creation and it's applications" Ph.d. programme.
While your admission project did indeed show a lot of practical skill and hard effort, we believe your theoretical understanding is somewhat deficit.
We asked for the best way to turn hydrogen into plutonium, not iron.
We encourage you to take another year of theoretical physics, and reapplying for t
Re: (Score:2)
I get so disappointed when I hear that the Pioneer mystery (or whichever one was curving unexpectedly) is solved using perfectly well known physics. Where are the new unknown rules that we can use to create new breakthrough technologies?
Re: (Score:1)
"You see, to be quite frank, Kevin, the fabric of the universe is far from perfect. It was a bit of botched job, you see. We only had seven days to make it."
Re: (Score:2)
confirmed with existing satellites, Jupiters moons (Score:2)
Why it took 52 years (Score:5, Interesting)
From what I have heard, the reason it took 52 years to get this spacecraft into space was political, not technical.
There is no doubt that the technology developed to measure these parameters is very impressive. The real question is whether or not it was worth the effort.
When I was at JPL in the 1980s a person who had published numerous papers in both experimental and theoretical relativity explained why scientists within the space program were not supporting this project. Since this conversation took place thirty years ago I must paraphrase:
"No modern theory of gravity predicts anything else, and if the measurements showed anything but the predicted results it would be assumed to be an experimental error. Unlike the technology used to search for gravitational radiation (which is also used to study the atmospheres of planets), the hardware in this spacecraft cannot be used for any other scientific experiment."
So for 52 years the money has been used for other science. For a much more worthy project read about the recently canceled LISA project.
If you wish to read about the politics of how a science project is chosen by NASA I can think of no better description that Steven W. Squyres' "Roving Mars" where he describes how the Mars Rovers were nearly canceled.
Re:Why it took 52 years (Score:4, Insightful)
No modern theory of gravity predicts anything else
Except Moffat's, of course.
And while every experimental anomaly is first dismissed as error, the fact (you remember those things, facts?) is that scientists have an excellent record of poking away at anomalies until a robust, consistent explanation is found. Sometimes the explanation is mundane--the Pioneer Anomaly, for example. Sometimes it is profound--the anomalous precession of the orbit of Mercury comes to mind, which was measured quite precisely in the 1850's, if I recall correctly, some sixty years before the underlying cause was found.
People who say things like this are simply ignorant of the history and timescales on which science actually operates. It is entirely implausible that a group of people who have collectively worked over hundreds of years to account for dozens of tiny numerical anomalies in extremely difficult precision measurements would suddenly throw up their hands and say, "OK, I guess we can ignore the data now!"
Re: (Score:1)
Like everything else, science does not have access to infinite resources. However, posts such as yours remind us there is an infinite amount of testing to do. For example, we could pose the question of whether or not a ball and a feather fall at the same rate as each other on Pluto, if dropped simultaneously. In the case where our need for resources outpaces our access to them, we must prioritize what is important.
One way of doing this is time and potential for payoff. Consider how many years the hypothetic
Re: (Score:3)
Very likely, but nobody would have been absolutely sure. Physicists would have looked at possible theories that were in accordance with the experimental results, and come up with other tests.
The Michelson-Morley experiment was similar in effect. People thought it very odd that it didn't show ether drift, but the theories were firmly established, and so physicists kept worrying at it. More expe
Re: (Score:2)
They cancelled LISA?! D=
If it's because there's no room in the budget for LISA and a shuttle-derived heavy-lift vehicle, I'm personally going to go kick a bunch of congresscritters in the jewels.
Re: (Score:1)
They cancelled LISA?! D=
It would appear so. [discovery.com] Well, not cancelled, just... well, "resting".
Awesome (Score:1)
I thought GPS demonstrated frame-dragging? (Score:2)
My understanding was that (satellite-based) GPS would give you a drastically inaccurate position reading without an algorithmic correction for frame-dragging. If so, it would seem that part of Einstein's predictions were validated quite a few years ago.
Re:I thought GPS demonstrated frame-dragging? (Score:5, Interesting)
No, GPS does takes General Relativity and Special Relativity into account, and confirms both nicely. Due to the motion of the spacecraft in orbit with respect to us on the ground, one would expect the GPS satellites to lose about 7 microseconds a day. However, because the satellites are further out of our gravity well, General Relativity predicts the satellites will gain about 45 microseconds a day. Basically, this means that if GR and SR were not taken into account, the GPS system would be useless after about 2 minutes.
Source: http://www.astronomy.ohio-state.edu/~pogge/Ast162/Unit5/gps.html [ohio-state.edu]
However, the effect of Frame Dragging is many orders of magnitude smaller, to the point where it will not have a measurable effect on GPS. To even have a hope of measuring it, Gravity Probe B had gyroscopes made from a set of the most perfect spheres ever manufactured. If you were to scale these spheres up to the size of the earth, the tallest mountain would be less than 1 meter tall.
This experiment was not very useful (Score:3)
The goal was to get numerical results to 1% accuracy, and the actual measurements only achieved %19 percent accuracy. This was due to a design error.
On top of that, other researchers made better measurements using other much cheaper satellites.
So they got scooped and their final results were not what they had planned. Not a complete failure, but not a real success either.
The next n (Score:1)
Which leads to the next n question:
If you took our solar system and placed it at the most significant Lagrange point between two galaxy's, would our understanding of physical constants change?
Re: (Score:3, Informative)
But you can confirm predictions....
Re:Picking nits (Score:4, Informative)
Fail (Score:4)
It doesn't state the theory has been confirmed, it says two of the predictions made by the theory has been confirmed.
Re: (Score:2)
Funky, one case in which the summary is more accurate than TFA. Never thought I'd see the say.
Space.com goofed its article title. Rather obviously just a goof though, since the article content itself doesn't make the same mistake.
Re: (Score:2)
Re: (Score:2)
I think it will suffice to say that looking for evidence to support what you *want* to be proven correct will often get in the way of gathering evidence for what is truly correct.
Hasn't worked that way in the past.
On little pet peeve, who is to say earth is spinning the magnetic field, and not the magnetic vortex spinning the earth?
Consider the relative difference in energy from the rotational energy of a spinning Earth and the energy content of the magnetic fields of Earth. I haven't done the math, but I bet the latter is a bunch of zeroes smaller than the former. That in itself is a very good reason for the interpretation.
Same goes for the claim that the Solar System revolves around the Sun. It's actually around a common center of gravity (which theoretically can be outside the Sun). But the Sun
Re: (Score:3, Funny)
Theory : There is ALWAYS 2 oranges in a bag.
Observation : A bag containing 5 oranges.
Conclusion: 2 oranges in a bag can reproduce
Re:first comment! (Score:5, Funny)
Uh oh.
Looks like someone didn't account for gravitational time dilation.
Re: (Score:2)
Please spew some more numbers in my direction. I can't get enough of them.
Re: (Score:2)
Brilliant. Making spam fun one post at a time :)
Re: (Score:1)
And please, keep up the good work of including the URL so its real easy to add to the ban list. Then, if this ever becomes a real business with useful, well-priced products it will still go bust because no-one will know about it.
Re:get more comments (Score:5, Informative)
The Slashdot D2 discussion system sucks. Turn it off in your account options and use the old D1. That's what I do. I much prefer to be able to see all the comments at one time.
Re: (Score:1)
Re: (Score:1)