If you shot a bullet in the air...
Discussion
ash73 said:
Yes it is, Olbers' paradox is resolved by a finite observable universe. Distant galaxies with a redshift greater than 1.4 are moving away from us faster than light, and we will never see them.
When you say infinite universe do you mean the empty space or the matter. I don't think there is infinity matter in our universe.AndrewEH1 said:
Damn you, lunchtime has extended to 2 hours and counting...ash73 said:
I mean both. The universe is a mathematical entity, think of it like a fractal; only a proportion is instantiated as far as our observation is concerned, but the universe and everything in it is literally infinite.
No it's not. Also in this field there's a massive difference between "literally" or "almost" infinite and actually infinite.ash73 said:
Yes it is, Olbers' paradox is resolved by a finite observable universe. Distant galaxies with a redshift greater than 1.4 are moving away from us faster than light, and we will never see them.
But how are they moving faster than the speed of light? I thought that was impossible (e=mc(2)) ash73 said:
The speed limit only applies to stuff moving within spacetime; the space between them is expanding faster than light, so their separation does the same.
Could you elaborate? I'm serious here, not taking the piss, I'm interested. I've just finished reading Timescape by Greg Benford where he explores Tachyons from his perspective in 1980 when he wrote it.Do people consider it is possible to exist in, or define a position outside of, Spacetime?
I'm versed in multidimensional universes and Einstein's work, but don't ask me to write a paper on it ...
The_Doc said:
ash73 said:
The speed limit only applies to stuff moving within spacetime; the space between them is expanding faster than light, so their separation does the same.
Could you elaborate? I'm serious here, not taking the piss, I'm interested. I've just finished reading Timescape by Greg Benford where he explores Tachyons from his perspective in 1980 when he wrote it.Do people consider it is possible to exist in, or define a position outside of, Spacetime?
I'm versed in multidimensional universes and Einstein's work, but don't ask me to write a paper on it ...
They are not moving in space time, but they are moving apart. Hence they can be moving apart faster than the speed of light, whilst each is not moving faster than the speed of light relative to the bit of space they are in.
Or two cars traveling along a road at 100mph in opposite directions. The rate at which they are moving away from each other is the equivalent of 200mph.
Substitute the road with space, the cars with stars/galaxies, and 100mph with speed of light, and there you have it. From the perspective if each, the other is moving away from it at twice light speed. Therefore neither will ever be visible to each other.
Substitute the road with space, the cars with stars/galaxies, and 100mph with speed of light, and there you have it. From the perspective if each, the other is moving away from it at twice light speed. Therefore neither will ever be visible to each other.
dvs_dave said:
Or two cars traveling along a road at 100mph in opposite directions. The rate at which they are moving away from each other is the equivalent of 200mph.
Substitute the road with space, the cars with stars/galaxies, and 100mph with speed of light, and there you have it. From the perspective if each, the other is moving away from it at twice light speed. Therefore neither will ever be visible to each other.
But their speed is only relative to each other, which doesn't get away from the fact that speed is about distance and only really defined when you have a point of observation. In your example, each other. On paper the limit of speed being c does not permit their speed being bigger than c when observed from a neutral or non relativistic point, our best mathematical model says.Substitute the road with space, the cars with stars/galaxies, and 100mph with speed of light, and there you have it. From the perspective if each, the other is moving away from it at twice light speed. Therefore neither will ever be visible to each other.
Car turning headlights on at speed of light I think, but perhaps not, classifies the same problem...
Edited by The_Doc on Sunday 5th October 17:31
ash73 said:
dvs_dave said:
Or two cars traveling along a road at 100mph in opposite directions. The rate at which they are moving away from each other is the equivalent of 200mph.
Substitute the road with space, the cars with stars/galaxies, and 100mph with speed of light, and there you have it. From the perspective if each, the other is moving away from it at twice light speed. Therefore neither will ever be visible to each other.
Light doesn't work like that; relativity actually says everything is relative except the speed of light. Time and distance flex but each would see photons of light from the other arriving at speed c.Substitute the road with space, the cars with stars/galaxies, and 100mph with speed of light, and there you have it. From the perspective if each, the other is moving away from it at twice light speed. Therefore neither will ever be visible to each other.
What was there before there was space? (post, a long time back)
St.Augustine answered that one, whe asked what God was doing before he created the Heavens and the Earth. "Creating a Hell for those who asked such questions"
A bullet in free flight through space would hit something eventually, but in the time it would take to get there, even some of the lead atoms in the bullet would have distintegrated.
JOhn
St.Augustine answered that one, whe asked what God was doing before he created the Heavens and the Earth. "Creating a Hell for those who asked such questions"
A bullet in free flight through space would hit something eventually, but in the time it would take to get there, even some of the lead atoms in the bullet would have distintegrated.
JOhn
tapkaJohnD said:
What was there before there was space? (post, a long time back)
St.Augustine answered that one, whe asked what God was doing before he created the Heavens and the Earth. "Creating a Hell for those who asked such questions"
A bullet in free flight through space would hit something eventually, but in the time it would take to get there, even some of the lead atoms in the bullet would have distintegrated.
JOhn
Oh no, don't bring Dog into it !! St.Augustine answered that one, whe asked what God was doing before he created the Heavens and the Earth. "Creating a Hell for those who asked such questions"
A bullet in free flight through space would hit something eventually, but in the time it would take to get there, even some of the lead atoms in the bullet would have distintegrated.
JOhn
Without a limited time scale or distance it would hit something eventually. One question though, would the bullet be constantly accelerating as gravity would be a factor?
Given the laws of comedy, it would take roughly 3-5 seconds to hit an unfortunate pigeon flying overhead.
Given Uk firearm laws, you'd probably be shot dead or in a physical relationship with your cell mate before it hit anything substantial.
Given the laws of comedy, it would take roughly 3-5 seconds to hit an unfortunate pigeon flying overhead.
Given Uk firearm laws, you'd probably be shot dead or in a physical relationship with your cell mate before it hit anything substantial.
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