There is no actual cutoff. The slower the speed, the lesser the effect; what counts as negligible is up to you. Even 1 MPH presumably demonstrates the same effect according to the same equations; it’s just so very very tiny that it hardly matters for anything. At higher speeds, the effect is much larger, to the point where one can hardly get anything done while ignoring it. But it’s presumably there at every speed, all the same; at least, whenever the theory predicts the effect to be observably large, the effect is indeed found and in the same strength as the theory predicts, so far as all experiments to date have discovered.
Why such a bugaboo about this theory? It conflicts with your intuition for how things should work? But that intuition has been shown wrong; it’s been demonstrated that clocks don’t remain synchronized if carried at suitable speeds relative to each other. So why the aversion to a theory which has given the right results?
So far, every scientific theory that has been shown to be wrong has been overturned, at least as far as I know, and at least within general consensus – there are always fringes, of course, within science as everywhere else. Newton’s laws were around for a couple of hundred years, then Einstein came round to suggest an alternative, which, after having withstood test after test, was broadly accepted almost immediately. There don’t seem to be any examples of scientists as a whole clinging to some dogma or paradigm in the face of disagreeing evidence that I can think of; however, you need some evidence (or at the very least, a better theory) first. There’s really no point to changing one’s views without compelling reason.
And by investigating it we are, what? Going to learn how to speed it up? Slow it down? What is the point? What more can we learn about it, and what relevance does it have to anything we can do in the material world?
Okay, it’s given us torches and lasers, but how else can we expect to harness its existence?
shrugs. Some people like to investigate how the world works, and history has shown this to be an abundant source of technological progress with no signs of stopping yet. But even if it wasn’t, some people would still be interested in investigating how the world works. If you don’t care for it, if you’d rather do something else with your time, well, you can, of course. No one’s forcing you to be a physicist…
So, you’d advocate an approach through which one just changes views at random? Maybe every few years? When the moon is in the seventh house, and jupiter aligns with mars? Really, how is there supposed to be any progress in understanding with such a system?
However, this ‘what has science ever done for us?’-debate always only remembers me of this, so I guess I’ll call it quits.
Here’s a simple example: The other day I sent a file from the east coast to the west coast via ftp, and then back again. The entire trip took only seconds to cover more than 5000 miles. When it came back, the create date had advanced by 3 hours. Obviously the effect of the file traveling at near light speeds
So you know scientists can observe time slowing down for fast-moving particles in particle accelerators, right? Radioactive particles take longer to decay, for example.
Now, the earth is moving through space, right? It’s circling the sun, and the sun is orbiting the center of the galaxy, and the galaxy itself is moving off toward the Great Attractor. So that means that any particle accelerators on earth are also flying through space at a fair clip.
Depending on the orientation of the accelerator, and the time of day, sometimes the particles are moving in the same direction as the earth, which means they’re traveling through absolute space faster. And sometimes the particles are moving in the opposite direction as earth, which means they’re moving through absolute space slower.
According to what you believe, that means that we should see a fluctuation in the time dilation they experience. We should see a range of different slowdowns in their decay, depending on whether they’re adding their motion to earth’s, or subtracting it. And, sometimes if conditions are right, we should even see them decay faster because their movement and earth’s movement cancel out, and now we’re the ones moving fast compared to them.
But that’s not what we see. The particles always decay the same way, just as if the earth was sitting stationary in space. So your way of looking at time and motion doesn’t agree with experimental evidence.
This is true for an individual or even a small research group. But people seem to get this idea that all scientists are part of this borg-like hivemind in which they all agree on everything. Nothing could be further from the truth. Scientists can form intense rivalries in which they constantly try to disprove each other.
Every single experiment that has been undergone to test relativity has shown it to be true. That isn’t to say that someone couldn’t design an experiment to disprove it, and if someone managed to do it he’d be a king among scientists. There’s no shadowy cabal trying to stifle heretical ideas, in fact they’re encouraged. You just gotta be able to back it up with experiment.
In fact, when quantum mechanics was first being developed, it took decades for it to gain acceptance among all physicists. And that’s not too surprising because it’s so counter-intuitive and weird. Einstein himself was one of the strongest critics of it, and spent basically half his life trying to disprove it. Ultimately, he turned out to be wrong, but his criticisms actually helped solidify the theory by forcing its proponents to test all his objections.
There is no cutoff. You probably have in your house equipment that could measure relativistic effects from objects moving at speeds of a few centimeters an hour. And the effects you would measure would be exactly in line with what the theory of relativity predicts.
What’s the appeal of questioning everything, anyway? When you’re putting away the groceries and put a can of beans in the cupboard, do you question the possibility that the can will still be there an hour later when you make supper? Why not?
“What is the appeal of questioning everything?”? Would you prefer people to just accept things on faith, or from authority? “Hey, this guy/group said so; it must be true!”
This is why I said “Nevermind about that; let’s cut to the chase, the brute observable facts”. I don’t care whether you describe the problem as “The clocks are tracking time accurately, but time passes at different rates along different journeys” or “Time is fixed, but clocks ‘break down’ and fail to track it accurately”. The phenomenon is the same; whether you say the “problem” is with time or with clocks, whatever you call it, the observed behavior is as I described, and any theory that claims otherwise is wrong. A theory is accurate only insofar as it makes correct statements about observable facts.
Scientists are not simply accepting things on authority… they perform experiments to test the ideas for themselves. It’s the experimental results which convince them. What more would you have them do, remain permanently in a state of “Well, who really knows anything?”, no matter how much proof they are able to accumulate? Like Chronos and others have said, should we sit around in maintained ignorance of every rule governing our lives, saying “Maybe this time, combining cereal and milk will cause a terrible explosion. Better not risk it…” and so on, or do we have the ability to gain confidence in our understanding of how the world works through repeated experiment?
Feel free to ask questions. My eyes are open for the possibility that tomorrow, objects will fall up and hot stoves will be pleasant to the touch. But that doesn’t mean I lack confidence in my current theories in the meanwhile…
Here’s a simple example: The other day I sent a file from the east coast to the west coast via ftp, and then back again. The entire trip took only seconds to cover more than 5000 miles. When it came back, the create date had advanced by 3 hours. Obviously the effect of the file traveling at near light speeds 