Stanford’s Gravity Probe B confirms two Einstein theories
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.
After 52 years of conceiving, building, testing and waiting, the science satellite has determined both effects with unprecedented precision by pointing at a single star, IM Pegasi, while in a polar orbit around Earth. If gravity did not affect space and time, Gravity Probe B’s gyroscopes would point in the same direction forever while in orbit. But in confirmation of Einstein’s general theory of relativity, the gyroscopes experienced measurable, minute changes in the direction of their spin as they were pulled by Earth’s gravity.
The findings appear online in the journal Physical Review Letters.
“Imagine the Earth as if it were immersed in honey. As the planet rotated its axis and orbited the Sun, the honey around it would warp and swirl, and it’s the same with space and time,” said Francis Everitt, a Stanford physicist and principal investigator for Gravity Probe B.
A lasting legacy
“GP-B confirmed two of the most profound predictions of Einstein’s universe, having far-reaching implications across astrophysics research,” Everitt said. “Likewise, the decades of technological innovation behind the mission will have a lasting legacy on Earth and in space.”
Stanford has been NASA’s prime contractor for the mission and was responsible for the design and integration of the science instrument and for mission operations and data analysis.
Much of the technology needed to test Einstein’s theory had not yet been invented in 1959 when Leonard Schiff, head of Stanford’s physics department, and George E. Pugh of the Defense Department independently proposed to observe the precession of a gyroscope in an Earth-orbiting satellite with respect to a distant star. Toward that end, Schiff teamed up with Stanford colleagues William Fairbank and Robert Cannon and subsequently, in 1962, recruited Everitt.
NASA came on board in 1963 with the initial funding to develop a relativity gyroscope experiment. Forty-one years later, the satellite was launched into orbit about 400 miles above Earth.
The project was soon beset by problems and disappointment when an unexpected wobble in the gyroscopes changed their orientation and interfered with the data. It took years for a team of scientists to sift through the muddy data and salvage the information they needed.
Despite the setback, Gravity Probe B’s decades of development led to groundbreaking technologies to control environmental disturbances on spacecraft, such as aerodynamic drag, magnetic fields and thermal variations. The mission’s star tracker and gyroscopes were the most precise ever designed and produced.
Played a role in developing GPS
Innovations enabled by GP-B have been used in the Global Positioning System, such as carrier-phase differential GPS, with its precision positioning that can allow an airplane to land unaided. Additional GP-B technologies were applied to NASA’s Cosmic Background Explorer mission, which determined the universe’s background radiation. That measurement is the underpinning of the “big bang theory” and led to the Nobel Prize for NASA’s John Mather.
“The mission results will have a long-term impact on the work of theoretical physicists for years to come,” said Bill Danchi, senior astrophysicist and program scientist at NASA Headquarters in Washington. “Every future challenge to Einstein’s theories of general relativity will have to seek more precise measurements than the remarkable work GP-B accomplished.”
Over the course of its mission, GP-B advanced the frontiers of knowledge and provided a practical training ground for 100 doctoral students and 15 master’s degree candidates at universities across the United States. Over 350 undergraduates and more than four dozen high school students also worked on the project, alongside leading scientists and aerospace engineers from industry and government.
Sally Ride, the first American female astronaut in space, worked on GP-B while studying at Stanford. Another was Nobel Laureate Eric Cornell, who also studied at Stanford.
NASA’s Marshall Space Flight Center in Huntsville, Ala., managed the Gravity Probe-B program for the agency. Lockheed Martin Corporation of Huntsville designed, integrated and tested the space vehicle and some of its major payload components.
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Learn a lot more on testing Einstein’s theories here h/t Dr. Leif Svalgaard via email
Einstein may have an equation that or two that work but they tell us nothing and prove nothing. Lorentz.s relativity has a different and easily understood concept and the Lorentz transformation are a law of nature using matter mechanics. They will lead to physics beyond relativity. This experiment with perfect balls is easily explained but with a different conclusion. When science or engineering require ever more complications and parts, often imaginary, to prove their theory they are marching in the wrong direction. The universe and indeed nature tends to the minimum for perfection.
“Stanford’s Gravity Probe B confirms two Einstein theories”
Oh dear. You can’t prove a scientific theory. What you can do is verify predictions based on that theory. Which is what the article states in the second para – “Stanford and NASA researchers have confirmed two predictions….”
New sub-editor needed .
Beautiful. I first became interested in science around 8 years of age, and this is precisely the sort of science that fascinated me back then. This is real science, and the climate science community could learn much from it if they were willing too do so.
I.e. Theory vs Empirical tests. Not Theory tested via theoretical computer models
When I first heard of the concept and required technology for this experiment I was stunned by their audacity-fantastic! Last year another of Einstein’s predictions- that while the speed of light was constant that at very short wavelengths- 10 to the -23 and -24 power cms there would be variations. Last year the radiation ? from implosion of an early galaxy arrived at Earth after about 13 billion years of travel. The two different wavelengths arrived 11 minutes apart as Einstein predicted. It was described in “Sky and Telescope” magazine. It leaves for dead all the the kindergarden climate science. I read Einstein mathematics for fun and my IQ measured in school sixty years ago was in his ballpark but I just cannot grasp how he imagined the concepts he did let alone convert them to exacting mathematics. To hurl a bunch of super gyroscopes to swirl through gravity waves while focussing on a distant star-how wonderful that real scientists of genius quality still exist. In spellbound admiration. Geoff Broadbent
Jim Masterson, sorry, noticed I basically doubled your comment earlier. Oops. Well, at least it’s a bit different. ☺
Was Einstein the true author of ‘Einstein’ theories?
‘The Annus Mirabilis papers are four articles pertaining to the photoelectric effect (which gave rise to quantum theory), Brownian motion, the special theory of relativity, and E = mc2, that Albert Einstein published in the Annalen der Physik scientific journal in 1905. These four works contributed substantially to the foundation of modern physics and changed views on space, time, and matter.’
His four most important papers were submitted for publishing on March 18 (he was only 26 two days earlier), May 11, June 30 and September 27 in year 1905.
It can be assumed that he worked on papers for at least some months earlier.
Incredible success for 24-5 year old; 4 years earlier at ETH Zurich ‘Although the final grades for Einstein fell below the 5 point average that was necessary to pass, Einstein’s 4.9 was rounded up to a 5, so he squeaked by’.
Einstein’s future wife, Mileva Marić (she was 4 years his senior), also enrolled at the Polytechnic that same year, the only woman among the six students in the mathematics and physics section of the teaching diploma course. Over the next few years, Einstein and Maric friendship developed into romance, and they read books together on extra-curricular physics in which Einstein was taking an increasing interest..
Mileva was deeply in love with Einstein, not very attractive and lame, in late January 1902 she gave birth to his illegitimate daughter called Lieserl. Albert and Mileva were married exactly one year later at Bern City Hall on January 6, 1903. She was just 28 Einstein was almost 24.
1905 was Einstein’s annus mirabilis, the miracle year. Albert published his four scientific papers that each marked an important breakthrough.
Mileva told a Serbian friend, “we finished some important work that will make my husband world famous.”
They were divorced in 1919, Albert was world-famous figure, but he never again produced physics on a par with the work of 1905.
How come this 24 year old genius that revolutionised physics, for five decades to follow produced very little in comparison?
Also Einstein agreed to sign over to Maric any future Nobel Prize money as part of the divorce settlement! Not money or property now, but ‘any future Nobel Prize money’, the result of the scientific achievements! Odd that.
Maric never made any claims, but content of her letter is telling:
’ But what can be done, one person gets the pearl and the other just gets the shell’.
2 words : “optical gyro”
Louis Savain says: (May 5, 2011 at 12:30 am)
I clicked on your link “Complete waste of time”
You are correct, it was a complete waste of my time.
ferd berple:
I have been accellerated for almost exactly 60 years at 1g now.
As my wife would put it, I am unfortunately still here and not at all near the end of the universe .
I will admit that my mass has increased, but not by relativistic amounts. The wife would argue that point, though.
Einstein was wrong on so many levels, it seems.
Ray says:
May 4, 2011 at 4:30 pm
Darn! Einstein is right again. That sucks… we will never be able to travel faster than light… at least in this space-time continuum.
Nothing can travel faster than light. So Ray if you turn into nothing you can travel faster than light. Or turn into heat as heat travelled with the edge of the universe as it expanded faster than light. Take your pick.
Jim Masterson says:
May 5, 2011 at 1:23 am
Your statement is somewhat confusing (mine may be no better). A uniform sphere (constant density throughout) creates a normal gravity field outside (as if the mass was concentrated at its center-of-mass). However, everywhere inside the sphere, the gravitational force would be zero.
You are correct that yours is no better. The density does not have to be constant, just only depending on distance from the center. And the field is not zero everywhere inside the sphere. If you substitute ‘spherical shell’ for ‘sphere’ your statement becomes correct.
On a more interesting note, one can ask where within the Earth gravity is the strongest? If you drill into the Earth and descent towards the center, gravity actually increases at first. [left to the student to explain why].
Tom in Florida says:
May 5, 2011 at 5:41 am
I clicked on your link [Louis Savain:] “Complete waste of time”
You are correct, it was a complete waste of my time.
Except it was an illuminating study of human stupidity
Louis Savain:
I have read all your posts and – with the exception of your offensive remarks at May 5, 2011 at 3:01 am – I admit that I have failed to make sense of any of them. So, I present my own understanding in hope that you will explain to me where you think it is wrong. My undertanding is as follows.
1.
Relativistic Theory says everything exists in the space-time continuum.
2.
The space-time continuum is an unchanging state that can be represented mathematically as being like a surface (with shape similar to a riding saddle).
3.
According to Relativistic Theory, a passage of time is described as being a movement from one place on the surface to another.
4.
According to Relativistc Theory, a movement in space is described as being a change from one place on the surface to another.
5.
The Relativistic Theory of the space-time continuum provides demonstrably correct predictions which indicates that it is correct.
6.
The unchanging state of the space time continuum is not consistent with Quantum Mechanics which presupposes that all possibilities co-exist until one of them becomes a reality.
7.
The theory of Quantum Mechanics provides demonstrably correct predictions which indicates that it is correct.
8.
Points 5 and 7 are not consistent because of point 6 (and this inconsistency is why Einstein refused to accept Quantum Mechanics).
9.
Relativistic Theory describes the overall behaviour of the universe throughout its existence while the theory of Quantum Mechanics describes behaviours of the smallest parts of the universe.
9.
A Grand Theory Of Everything would reconcile Relativistic Theory with Quantum Mechanics and, thus, provide a description of the universe at all scales.
10.
Some people who believe in ‘free will’ have difficulty with the concept of the space-time continuum because that concept implies all actions are fixed and, therefore, no person can choose an action (this disagrees with the ‘feeling’ that we do choose between possible actions).
11.
I believe in ‘free will’ (I am an Accredited Methodist Preacher) but – like most others who believe in ‘free will’ – I have no difficulty accepting that Relativistic Theory is ‘true’.
12.
Our best descriptions of the universe are defined by empirical data and the ability of those description to make accurate predictions, so there is no reason to suppose that our best descriptions of the universe have to agree with our personal experiences.
13.
Unless and until the Grand Theory Of Everything is developed then considerations of ‘free will’ are not relevant – and cannot be relevant – to scientific descriptions of the universe at any scale.
OK. That is an itemised statement of my understanding of the matter. Please tell me what you think is wrong with my understanding.
Richard
ferd berple;
On a more serious note;
If time, as Einstein suggests, does not exist but is only a succession of events, the succession of events like passenger metabolism, nuclear decay etc, will happen at the same rate aboard the space ship as on the earth.
Lorentz transformation of light emitted from the space ship to earth will make the space ship appear to travel slightly below c as seen from earth. As seen from the space ship, it will be steadily accellerating and will within a year reach c if accellerated at 1g.
After travelling to the end of the universe in 60 years and back in another 60 years (assuming the travellers will stop for a look at the view) the metabolism and nuclear decay on board will have seen 120 years as will the people on earth.
The big problem is to find a propellant that will allow such travel.
Dan says:
May 5, 2011 at 6:41 am
I have been accellerated for almost exactly 60 years at 1g now.
As my wife would put it, I am unfortunately still here and not at all near the end of the universe .
But in the wrong direction 🙂
@ur momisugly Louis Savain:
That sounds a lot like the ‘ol “what happens at the edge of the universe” problem.
If you’re standing at the edge of the universe, and stick out your hand, where does it go?
“an unexpected wobble in the gyroscopes changed their orientation and interfered with the data. It took years for a team of scientists to sift through the muddy data and salvage the information they needed.”
Ah,
Hmmm.
Leif Svalgaard says:
May 5, 2011 at 6:58 am
On a more interesting note, one can ask where within the Earth gravity is the strongest? If you drill into the Earth and descent towards the center, gravity actually increases at first. [left to the student to explain why].
Increase in density. Subcrustal matter is denser and so the intrepid terranaut is closer to a stronger source of gravitation than at the surface soon after (s)he starts the descent. Gravitation falls off with the square of the distance, so the pull is stronger when the distance to the denser material is less.
Louis,
“There are other equally irrefutable proofs of the non-existence of space but the one above is sufficient.”
Sure, I’m going to accept the word on whether an explaination is sufficient from the guy “debunking” Einstein by merely claiming that he doesn’t like it. 🙂 (ie. “infinite regression”.) That’s a philosophical arguement, not a scientific one.
As a matter of fact, the regression isn’t a given. One article I’d read a year or two ago suggested that space time is like a web mesh. Each joint of the net is a “point” in space that something can occupy. These “points” can be stretched and compressed toward and away from each other, however. This “distance” is basically an energy.
This is a rather elegant framework and helps to understand things like the attenuation of gravity over distance. Rather than imagining that every piece of matter interacts with every other piece of matter in the universe, instead one could imagine that that matter warps its mesh and the points adjacent to its mesh. Those adjacent points modify THEIR adjacent points, etc, etc, ad infinitum, to lesser and lesser effect as you propogate away from the initial disturbance.
Lief:
Is it possible to expand space without expanding time?? … or conversely, can space contract without contracting time?
What happens to all these questions if we simply give the universe, a velocity, which induces apparent mass (hence gravity) into everything? I wish I had answers, that I could hang my hat on. GK
Mark Wagner says:
May 5, 2011 at 7:22 am
If you’re standing at the edge of the universe, and stick out your hand, where does it go?
Mark, I think the answer is that your hand just keeps reaching out. In other words, you can never catch up with the “edge” of the expanding Universe.
Leif,
I guess in order to ‘rescue the data’ the scientists must have found some systematic ‘aberrations’ in the gyroscope headings. Have they documented those and found satisfactory explanations for them?
tallbloke says:
May 5, 2011 at 8:04 am
I guess in order to ‘rescue the data’ the scientists must have found some systematic ‘aberrations’ in the gyroscope headings. Have they documented those and found satisfactory explanations for them?
In order to interpret the data you must first understand your instrument. Such understanding often comes after the experiment when unexpected effects show up. But, yes, they have documented this and, more importantly, understand why they occurred. This is part of the reason it took so long. Their result is rock solid. It is every scientists dream to prove Einstein wrong, so much of their analysis was fueled by this dream. As usual, Einstein came out right.
G. Karst:
At May 5, 2011 at 7:48 am you ask Lief:
“What happens to all these questions if we simply give the universe, a velocity, … ?”
I ask, a velocity of the universe relative to what?
Richard
G. Karst says:
May 5, 2011 at 7:48 am
Is it possible to expand space without expanding time?? … or conversely, can space contract without contracting time?
Time does not ‘expand’, just rolls on. It is important to keep the notion of ‘expanding space’ clear of confusing elements. Nothing can move through space faster than light, but space itself can expand [and does] at any speed. Some of the farthest galaxies found have a red shift in excess of 10 http://cosmiclog.msnbc.msn.com/_news/2011/01/26/5920882-hubble-spots-farthest-galaxy-again which if the galaxy was moving through space would amount to 10 times light-speed. But the galaxy is not moving through space and time in that galaxy has not been distorted. Space has just expanded. The cosmic microwave radiation has a red shift of 1089 [one thousand eighty-nine], meaning that space has expanded by that factor since the radiation was emitted, some 379,000 years after the Big Bang. What we see is radiation emitted at a temperature of about 3000K, and which [wavelength] has been stretched by the expansion, so that it now is 1089 times longer, corresponding to a temperature of 2.725K.
Louis Savain says:
May 4, 2011 at 10:30 pm
dt/dt proves via extremely simple logic (which apparently went over your head) that, contrary to the claims of Albert Einstein’s (and many others), there is no such thing as a time dimension. That is all. This is true whether or not you or Svalgaard or anybody else likes it. I must admit that I do get a sense of satisfaction from rubbing the scientific community’s nose in their own excrement. I can’t help it. It’s the rebel in me.
According to your logic there is no such thing as a space dimension, since dx/dx and dy/dy and dz/dz are stable!
Think again.
Time is a measure of fourspace adjusted to human biology and mentality. In a science fiction scenario, one could describe “life” that evolved in what is for us the x direction while remaining well defined in t,y,z. When reaching a certain x, life would end. Whereas t,y and z could be explored and expanded into.
It is the change in the space variables that forces us to use time as time, and it is all due to the biology of the planet earth. IMO.