no, everything is not relative
I been hearin' that crap for years and it just ain't true
Consider it relatively true!henry quirk wrote: ↑Tue Aug 04, 2020 2:21 amno, everything is not relative
I been hearin' that crap for years and it just ain't true
Anything you like. The point of special relativity is not that the speed of light is constant, it is that regardless of your inertial frame, you will measure the speed of light in a vacuum as c. But then, wherever there are agents with the means to measure, there is no absolute vacuum. Again, it's yer epistemology, not ontology.
Okay, SO you are travelling at the speed of light and you turn on a flashlight towards the direction you are travelling; what happens?uwot wrote: ↑Tue Aug 04, 2020 2:56 pmAnything you like. The point of special relativity is not that the speed of light is constant, it is that regardless of your inertial frame, you will measure the speed of light in a vacuum as c. But then, wherever there are agents with the means to measure, there is no absolute vacuum. Again, it's yer epistemology, not ontology.
damn good questionSculptor wrote: ↑Tue Aug 04, 2020 3:06 pmOkay, SO you are travelling at the speed of light and you turn on a flashlight towards the direction you are travelling; what happens?uwot wrote: ↑Tue Aug 04, 2020 2:56 pmAnything you like. The point of special relativity is not that the speed of light is constant, it is that regardless of your inertial frame, you will measure the speed of light in a vacuum as c. But then, wherever there are agents with the means to measure, there is no absolute vacuum. Again, it's yer epistemology, not ontology.
You wouldn't be able to switch on the light. The way that special relativity is usually reported is that time stops when you are travelling at the speed of light. What it means in practise is that nothing happens. All the big stuff that happens; decisions to turn on flashlights for example, are dependent on many smaller quantum events, such as a photon passing from one atom to another. So there's all sorts of exchanges going on, but for simplicity consider two atoms moving in parallel paths, one a short distance above the other. If those two atoms are stationary, a photon can pass from one to the other in the shortest amount of time and the effect it produces happens as quickly as possible. If the two atoms are travelling at the speed of light though, the photon cannot pass from one atom to the other, because to do so would mean going faster than photons are wont to go. The effect never happens, nor do any others, clocks therefore stop ticking and for practical purposes 'time' stands still.
stasisuwot wrote: ↑Tue Aug 04, 2020 3:39 pmYou wouldn't be able to switch on the light. The way that special relativity is usually reported is that time stops when you are travelling at the speed of light. What it means in practise is that nothing happens. All the big stuff that happens; decisions to turn on flashlights for example, are dependent on many smaller quantum events, such as a photon passing from one atom to another. So there's all sorts of exchanges going on, but for simplicity consider two atoms moving in parallel paths, one a short distance above the other. If those two atoms are stationary, a photon can pass from one to the other in the shortest amount of time and the effect it produces happens as quickly as possible. If the two atoms are travelling at the speed of light though, the photon cannot pass from one atom to the other, because to do so would mean going faster than photons are wont to go. The effect never happens, nor do any others, clocks therefore stop ticking and for practical purposes 'time' stands still.
Anyway, 'material bodies' cannot travel at c, not even individual particles. So at any fraction of c, should someone turn on a flashlight and chase the beam, all the exchanges going on in their brain are stretched out. Here's some slides from a show I was doing before the lock down. It's probably quicker to go through those than read me blabbing on about it: https://www.blogger.com/blogger.g?blogI ... c=postname
I'll throw you a rope.
But the point is surely that my life continues, but at a rate to you an observer that is stopped. But not stopped for me.uwot wrote: ↑Tue Aug 04, 2020 3:39 pmYou wouldn't be able to switch on the light. The way that special relativity is usually reported is that time stops when you are travelling at the speed of light. What it means in practise is that nothing happens. All the big stuff that happens; decisions to turn on flashlights for example, are dependent on many smaller quantum events, such as a photon passing from one atom to another. So there's all sorts of exchanges going on, but for simplicity consider two atoms moving in parallel paths, one a short distance above the other. If those two atoms are stationary, a photon can pass from one to the other in the shortest amount of time and the effect it produces happens as quickly as possible. If the two atoms are travelling at the speed of light though, the photon cannot pass from one atom to the other, because to do so would mean going faster than photons are wont to go. The effect never happens, nor do any others, clocks therefore stop ticking and for practical purposes 'time' stands still.
Anyway, 'material bodies' cannot travel at c, not even individual particles. So at any fraction of c, should someone turn on a flashlight and chase the beam, all the exchanges going on in their brain are stretched out. Here's some slides from a show I was doing before the lock down. It's probably quicker to go through those than read me blabbing on about it: https://www.blogger.com/blogger.g?blogI ... c=postname
Life is tough and to live successfully requires continous effort (work and learning) and enduring discomfort, disappointment, and overcoming endless difficulties, which is what living is. If you expect everything to be easy and nice and never having to experience any pain or disappointment you will probably be miserable. For those who know the value of life, and that nothing of real value comes easy or without great cost, the challenges of life are just part of the great adventure that achieving and being all one can costs and are only incidentals in one's overall enjoyment of a fufilled life worth living. Knowing that is the life one is living is being happy all the time, even during the hardest times.Dubious wrote: ↑Tue Aug 04, 2020 1:40 am...just for the record, sometimes I'm miserable and sometimes I'm not. Only idiots are happy all the time.RCSaunders wrote: ↑Tue Aug 04, 2020 12:46 am Just for the record, if your life is miserable, it's your own damn fault.
Well life is just stuff that happens. If you were to avoid colliding with something, nothing would happen to you while you are travelling at the speed of light. From the point of view of anyone not travelling at the speed of light, you wouldn't know you were alive. It is only when you drop to sub light speed that stuff starts to happen again and your life continues. Conceivably, you could get on a cosmic bicycle that you peddle around the universe at light speed until all the stars burn out and not be a day older in terms of stuff happening to you.Sculptor wrote: ↑Tue Aug 04, 2020 5:29 pm But the point is surely that my life continues, but at a rate to you an observer that is stopped. But not stopped for me.
Were I to be going half the speed of light, then my life would appear slowed down to you, but as per usual to myself. When I got back to earth everyone would be long dead, but I'd only have experienced a shorter time.
??
Okay, so what you are saying is that if we could do the impossible and travel at the speed of light it would be instant in terms of our own life.uwot wrote: ↑Tue Aug 04, 2020 6:36 pmWell life is just stuff that happens. If you were to avoid colliding with something, nothing would happen to you while you are travelling at the speed of light. From the point of view of anyone not travelling at the speed of light, you wouldn't know you were alive. It is only when you drop to sub light speed that stuff starts to happen again and your life continues. Conceivably, you could get on a cosmic bicycle that you peddle around the universe at light speed until all the stars burn out and not be a day older in terms of stuff happening to you.Sculptor wrote: ↑Tue Aug 04, 2020 5:29 pm But the point is surely that my life continues, but at a rate to you an observer that is stopped. But not stopped for me.
Were I to be going half the speed of light, then my life would appear slowed down to you, but as per usual to myself. When I got back to earth everyone would be long dead, but I'd only have experienced a shorter time.
??
Note to pedants: No, you can't travel at light speed and the idea of a human cycling that fast is silly.
If you were magically traveling at the speed of light, I assume the flashlight beam would not project ahead of you when you flip it on because you are moving as fast as the photons being emitted from your flashlight and you could not catch up with the photons coming out of the flashlight because they would be traveling at the same speed you are. If you faced the flashlight to the rear, the photons from its beam would travel backward at the speed of light, however, you wouldn't see anything behind you because the reflected light photons hitting objects behind you wouldn't catch up to you. At light speed, your field of vision would be restricted to a cone in the direction of your movement and you would only see light photons that were traveling toward you.Sculptor wrote: ↑Tue Aug 04, 2020 3:06 pmOkay, SO you are travelling at the speed of light and you turn on a flashlight towards the direction you are travelling; what happens?uwot wrote: ↑Tue Aug 04, 2020 2:56 pmAnything you like. The point of special relativity is not that the speed of light is constant, it is that regardless of your inertial frame, you will measure the speed of light in a vacuum as c. But then, wherever there are agents with the means to measure, there is no absolute vacuum. Again, it's yer epistemology, not ontology.