We constantly say that Einstein’s General and Special theories of relativity have passed many different tests, insenuating their accuracy.
Before Einsten, we tested Isaac Newton’s theories, which also passed with accuracy until Einstein came along.
What’s to say another Einstein/Newton comes along 200-300 years from now to dispute Einstein’s theories?
Is that even possible or are his theories grounded in certainty at this point?
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We actually already know he didn’t have it truly correct.
He got a bit closer to describing a bit of reality than Newton did. We still use Newtons theories, because if you want to build a bridge, they work fine and are easier to work with.
If you want to build a rocket, you want Einstien level works.
But people building rockets are somewhat aware that his theorems aren’t how things really work, they are just close enough that they will do.
If you want to build a particle reactor, you need to think about post-Einstien quantum mechanics, and some very fiddly new theories indeed. And if we don’t break our high tech society, one day, we shall likely need to work with yet another set of theories, but stick to the old simple ones for such down to earth stuff as particle accelerators.
>What’s to say another Einstein/Newton comes along 200-300 years from now to dispute Einstein’s theories?
Well, nothing, but you’ve got some misconceptions. First, science isn’t about “knowing what’s right” with 100% certainty forever. Science is about what we know right now based on our observations and whether our predictions match them. If something works now, it’s right until something better replaces it. We don’t say “we can’t conclusively prove relativity is 100% perfect and correct for all time therefore we must assume it’s wrong.”
Second, is that you’re not really understanding what “right” means. That’s not really a well-defined term the way you’re using it. Newton’s laws of motion are still remarkably accurate and we use them every day. 99.9% of the time that you use Newton’s laws of motion, they will be “right.” It’s not that often that new theories completely overturn old ones. More often than not, new theories build on older ones by improving and refining them, which makes the old ones less accurate, but not “wrong” per se.
First thing, we don’t. But that’s the thing about Science is that we never assume what we know is the truth. It’s always evolving and changing.
As technology and measurements progressed, we started noticing discrepancies with Newton’s model.
One of the more famous examples is Mercury’s orbit. Mercury’s orbit is impossible with Newtonian gravity. It’s too “wobbly”. When we discovered that, we still thought Newton was correct, so we started coming up with ideas on how to make it work. The one that worked best was that there was another planet closer to the sun that was pulling Mercury; we called it Vulcan. They could never find it, but because the math said Vulcan had to be there, they assumed it was.
Then Einstein published General Relativity, and that allowed Mercury’s orbit to exist without Vulcan. Mercury is close enough to the sun where the relativistic effects of the Sun’s mass was messing with its orbit. With that explination and the complete lack of evidence of Vulcan, we eventually accepted GR and Vulcan faded into myth.
Something similar to what happened with Newtonian Gravity would need to happen to GR for us to really start looking for a new theory. Right now, with our current technology, we have nothing. GR has passed every test perfectly. The closest thing we have to a discrepency is Dark Matter, but we have other observations that heavily suggests that it’s actually undetected mass rather than a failure of our model of gravity.
GPS satellites move very fast. They have very very accurate atomic clocks. They are subject to lower gravity than if they were on the ground. They need to communicate with ground-based atomic clocks. These things mean time dilation would be a problem and have calculated the effect that dilation has so the GPS satellites account for this.
He doesn’t have it right, he just has it more right than Newton. Someone in the future will likely be more right. And so on until we’ve finally unlocked every secret in the universe.
And Newton is still right. Newton gets us around the planet (GPS notwithstanding) and to the Moon, and space probes to other worlds.
Newton was not wrong! It is more accurate to say his theory of gravity is less *complete* than Einstiens, as Einstein’s can be used in *any* frame of reference (compare any two speeds) while Newton’s works well (but only for human relevant speeds on and around Earth).
Newton’s laws can put a GPS satellite in orbit, but GPS requires Einstein in order to work on the software end because the radio communications and software process fast enough that the limits of Newtonian mechanics start to impact accuracy. The satellites are high enough and fast enough that they move quite a bit between each ‘ping’ they broadcast (which your phone picks up) that without adjustment for that speed & altitude the accuracy is lost, but we know enough about their Newtonian orbits that the software in your phone can make the appropriate filter/correction and put your location to within a few meters. If/when the US government ever decides it is necessary to turn off that “correction” factor, you’ll see accuracy expand out to something like a few hundred meters — you’ll know what part of a city you are in, but not which block or building.
In much the same way, Alan Turing was not wrong about computers (he was a freakking genius), but his knowledge of processor chips was zero because they hadn’t been invented yet. Had he lived he would have learned, but that’s another story. His fundamental programming abilty was correct, but he lacked knowledge of how to get the hardware to do what he needed except through racks of analog gears and switches. His knowledge was incomplete, not incorrect.
And so it is with any science or technology. Gregor Mendel worked out the math and “flow chart” of how genetics worked from generation to generation (1850s), but it was a full century before anyone worked out what the involved molecules were (Watson and Crick, DNA in the 1950s) and here we are coming up on two full centuries still trying to figure out the details of how DNA works. Yet if you take a high school biology class you learn the charts and tests Mendel developed because they still work. They are still correct — they are not wrong, they are simply incomplete. Watson and Crick and the nature of DNA are a different unit in biology, and then genetics is still a third unit.
And it’s the same with gravity – Newton was right, but only for the sorts of speeds and environments humans are used to operating in. Einstien upgraded Newton only on account of he removed that limitation so we can do the equations for *any* speed or environment we can find in the observable universe. The holy grail, which we are still looking for, is to figure out how to do this for all of these environments as well as those we *can’t* observe, such is those inside a singularity (a black hole) or in a hypothetical universe with different physical laws or conditions. Right now, every hypothetical or un-observable requires a different equation, our knowledge is limited, but once that breakthrough is made we’ll have a third name to add to our list of gravity theorists. Someday!
Their theories were right given the evidence they had at the time. We learn new stuff everyday and one day some genius will come along with access to more evidence and improve it.
Newton’s theories give the same answers as Einstein’s theories up to a certain point of measurement accuracy.
A baseball pitched at 10 m/s riding on the back of a train traveling 10 m/s in the same direction, according to Newton, would be traveling 20 m/s. But according to Einstein, that baseball will be moving at 19.9999933287 m/s. Not exactly the same. But if your best speedometer only reads to an accuracy of 0.01 m/s, these are basically the same exact answer as far as anyone can tell.
The only thing that tipped Einstein off to the idea that Newton’s theories needed correction in the first place is that science was starting to get very precise. So precise that predictions made with Newton’s theories were starting to drift away from experimental evidence. Einstein wasn’t pulling random crap out of his ass as fanfiction for how the universe works, and he just happened to be right. He was very specifically looking for a way to correct Newton’s theories to re-align with the data. And the explanation he found has, as far as we can tell, succeeded at doing exactly that.
Is it possible that some day science will advance so far that predictions from Einstein’s theories start to drift away from the data? Sure. No reason to say they never could. But we don’t yet seem to have any evidence that this is the case. General relativity appears to have passed every test we’ve managed to throw at it so far… Or rather, the tests that it failed haven’t ruled out other factors, so we can’t say for certain that general relativity is the problem.
*IF* general relativity is one day replaced by a more comprehensive theory, it probably won’t be as meaningfully different as you’d think. General relativity as it is right now matches everything we currently see. Any more accurate system will also have to match everything we currently see, meaning it will have to behave exactly like general relativity already does, just with extra steps.
Every physicist on the planet would be overjoyed, as long as the new equations hold up to testing the same way. Scientists dont tend to be bothered by new information or being proved wrong.
If you take a substance made of particles that has a half life of say, 1 second, then after 1 second, half of the particles will be left, and the other half will have decayed into something else. Special relativity states that t’ = t/sqrt(1 – (v/c)^2), where t’ is the time that has passed for you, t is the time that has passed for the particles (in their rest frame), and v is the velocity of the particles relative to you. Experimentation has shown that if you move those particles really fast, like 99% the speed of light, when 1 second has passed for you, fewer than half of the particles will have decayed, and the results agree with the equation.
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