Einstein's Relativity and Everyday LifeThank you
never heard of relativistic speeds
But in a relativistic world, things are not simple. The satellite clocks are moving at 14,000 km/hr in orbits that circle the Earth twice per day, much faster than clocks on the surface of the Earth, and Einstein's theory of special relativity says that rapidly moving clocks tick more slowly, by about seven microseconds (millionths of a second) per day.
Also, the orbiting clocks are 20,000 km above the Earth, and experience gravity that is four times weaker than that on the ground. Einstein's general relativity theory says that gravity curves space and time, resulting in a tendency for the orbiting clocks to tick slightly faster, by about 45 microseconds per day. The net result is that time on a GPS satellite clock advances faster than a clock on the ground by about 38 microseconds per day.
Its interestingThe "speed of light" can be thought of as a law, a law of physics. It pops out of what are called Maxwell's field equations, the speed of light is a characteristic of those equations.
So because it represents a law, it does not change, it cannot change, this is the reason it is constant. That constancy is often a source of puzzlement until one realizes that it is inherently a law, or a consequence of a law.
Einstein's theory of special relativity -> relativistic speed.
Maybe:Part of the reason nothing can go at the speed of light is the energy required is infinite. The nearest thing we can hit to the infinite that we know of in the universe is black holes (infinite density). There might even be some relationship there.
If your black hole is non-rotating, the singularity is nothing but a mere point. If all the mass is compressed into a single, zero-dimensional point, then when you ask about density, you are asking “what happens when you divide a finite value (mass) by zero?”
If you need a reminder, dividing by zero is mathematically bad; you get an undefined answer. Thankfully, perhaps, non-rotating black holes aren’t what we have in our physical Universe. Our realistic black holes rotate, and that means that the interior structure is much more complicated. Instead of a perfectly spherical event horizon, we get a spheroidal one that’s elongated along its plane of rotation. Instead of a point-like (zero-dimensional) singularity, we get a ring-like (one-dimensional) one, which is proportional to the angular momentum (and the angular momentum-to-mass) ratio.
Unfortunately for us, there’s no way we know of to test this experimentally or observationally. We might be able to calculate – to help us visualize – what we theoretically expect to happen inside of a black hole, but there’s no way to get the observational evidence.
The closest we’ll be able to come is to look to gravitational wave detectors like LIGO, Virgo and KAGRA, and to measure the ringdowns (i.e., the physics in the immediate aftermath) of two merging black holes. It can help confirm certain details that will either validate or refute our current best picture of black hole interiors. So far, everything lines up exactly as Einstein predicted, and exactly as theorists expected.
Einstein was a big "thought experiment" person, he did that a lot. One of the questions he pondered when young, perhaps a few years before his 1905 paper, was "what would a light wave look like if I ran along side it" (so to speak).Its interesting
Always "known" that speed of light is fixed,
this came up as I was reading some flim flam article about red and blue shift
all of which I also "know"
But the flim flam was very missing on why the question I gave did not violate the faster than light
Seems that the velocity vectors dont just add up,
Thanks all ,
given me a new set of stuff to read up on
wonder what happens if a "bullet" could be sent near speed of light, etc,
Total Bull-hockey. Another without propellant and go beyond the principle of action-reaction opium dream like the EMDrive. https://forum.allaboutcircuits.com/threads/reactionless-drives.104359/By the Magic of Goole always listening to what I type
this popped into mail box
Seems some one has idea of how to go fast, even if it takes time to get to speed, using the things change mass as speed changes of special relativity
https://arstechnica.com/science/201...e-would-provide-thrust-in-different-universe/Friends Don't Let Friends Use Reactionless Drives In Their Universes.
Helical EngineConservation of momentum should not be ignored
Now, the author argues that because the inertial mass grows nonlinearly with speed, there is an average acceleration in one direction. Even better, this difference increases as the peak particle speed gets closer to the speed of light. Unfortunately, the Universe just doesn't quite work like that.
So, let's just state up front: this drive won't work. The problem is that, even though the author does a very nice simulation, he has left out the fields that do the accelerating. When we accelerate ions using a magnetic or electric field, the ions push back on the field. There is an equal and opposite force exerted on the electrodes and coils that produce the fields, and those just happen to be in the spaceship, too.
In the first step, where we accelerate the mass to a high relativistic speed, we also accelerate the cylinder in the opposite direction. Now, in special relativity, we don't conserve energy and momentum separately. Instead, they are conserved together. If you only consider momentum (and not energy), then you will find net forces everywhere due to inertial mass changes—things get heavier as they approach the speed of light. This is exactly what the author has found. If you consider energy and momentum simultaneously, those forces will suddenly disappear.
This is where the increase in inertial mass comes from in the first place: energy is sucked out of the field and turned into mass. When the particles are slowed, that mass is given up as photons in the field, which slow the cylinder as they are absorbed. What is the net force? Zero, 0N of force.
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by Jake Hertz
by Robert Keim