speed of light?

[BorkBorkBork]

danwins said:

Evening all.

Just had a good debate with my daughter and thought I'd get your input.

We all know you cant travel faster than light for various reasons, Mass, time etc, but my daughter put up a valid question. Hundreds of years ago we proved everything revolved around the earth,we were wrong, we proved we were the center of the galaxy, we were wrong again... so on and so on. Science is always proving then disproving theories So is there a possibility in a few hundred years we could be wrong about traveling faster than light?

Dan

I predict the universe is a giant computer. And the speed of light is essentially a proxy for the maximum power and bandwidth of the CPU. So, if God upgrades his DX4-100, instead of going faster than the speed of light, light will just go faster. It is a massless particle after all.

[General Price]

Dr Jekyll said:

andy_s said:

'Gravity also moves at lightspeedish, so if the sun were to suddenly disappear we'd continue to orbit nothing for another 8 minutes

So the sun might have disappeared 7 minutes ago but we just can't tell yet?

That was one of the stoned ponderings of my youth along with the size of the universe.

It used to make my headache.

It can't be infinite,it has to end sometime.

[andy_s]

Dr Jekyll said:

andy_s said:

'Gravity also moves at lightspeedish, so if the sun were to suddenly disappear we'd continue to orbit nothing for another 8 minutes

So the sun might have disappeared 7 minutes ago but we just can't tell yet?

Yeah, apparently so; 'moves' wasn't the best word - gravity being spacetime distortion n all.

[LordGrover]

General Price said:

That was one of the stoned ponderings of my youth along with the size of the universe.

It used to make my headache.

It can't be infinite,it has to end sometime.

Our Brains Are Too Puny....

[67Dino]

LordGrover said:

General Price said:

That was one of the stoned ponderings of my youth along with the size of the universe.

It used to make my headache.

It can't be infinite,it has to end sometime.

Our Brains Are Too Puny....

I find it a lot easier to think the universe (perhaps not this one, but something) is infinite in time, so has always existed and always will.

The alternative is at some point it didn’t exist and then suddenly did. If so, what made it exist since there was nothing there before? Makes no sense to me.

Does bend the brain a bit.

The other one that gets me thinking is whether any of this exists outside our (or some other consciousness’s) awareness of it. If we weren’t here, exactly what would be the point?

[Ayahuasca]

andy_s said:

Dr Jekyll said:

andy_s said:

'Gravity also moves at lightspeedish, so if the sun were to suddenly disappear we'd continue to orbit nothing for another 8 minutes

So the sun might have disappeared 7 minutes ago but we just can't tell yet?

Yeah, apparently so; 'moves' wasn't the best word - gravity being spacetime distortion n all.

The ‘gravity is space-time distortion’ thing seems graspable when talking about galaxies and planets, but did space-time distortion give me all those cuts and bruises when I fell off my bicycle? And why can’t I get a raisin to orbit an orange? Does it only work for big things?

[Lost ranger]

No problem getting a raisin to orbit an orange, you'd just have to make sure you were far enough away from large objects for the orange's gravity to be the main influence.

[Simpo Two]

Lost ranger said:

No problem getting a raisin to orbit an orange, you'd just have to make sure you were far enough away from large objects for the orange's gravity to be the main influence.

I was wondering how fast it would orbit. How many times would it go round the orange in a minute if it was, say, 24" from the orange's centre? Do any PHers have the 'math' for that?

[deckster]

Simpo Two said:

Lost ranger said:

No problem getting a raisin to orbit an orange, you'd just have to make sure you were far enough away from large objects for the orange's gravity to be the main influence.

I was wondering how fast it would orbit. How many times would it go round the orange in a minute if it was, say, 24" from the orange's centre? Do any PHers have the 'math' for that?

https://en.wikipedia.org/wiki/Orbital_speed

Fill your boots

[Simpo Two]

deckster said:

https://en.wikipedia.org/wiki/Orbital_speed

Fill your boots

It doesn't mention oranges or raisins

If I had a gravity-free vacuum box, I could do a practical test with a stopwatch...

[deckster]

Simpo Two said:

deckster said:

https://en.wikipedia.org/wiki/Orbital_speed

Fill your boots

It doesn't mention oranges or raisins

If I had a gravity-free vacuum box, I could do a practical test with a stopwatch...

Pretty sure I saw an advert for one of those in the Readers Digest once.

[cacbyname]

Simpo Two said:

I was wondering how fast it would orbit. How many times would it go round the orange in a minute if it was, say, 24" from the orange's centre? Do any PHers have the 'math' for that?

Assuming the orange weighs 200g, I think at 2ft the raisin would take 66.9hours to orbit the orange.

[Baron Greenback]

If gravity alter the path of light, especially black holes, no light escapes the event horizon. The light below some of it is performing a 180 degree path around the back and comes back towards camera.



What happens to the light going straight towards the event horizon does it speed up until hitting the black hole or as the theory goes nothing can go faster and just stays are speed of light?

[Simpo Two]

cacbyname said:

Assuming the orange weighs 200g, I think at 2ft the raisin would take 66.9hours to orbit the orange.

I'll buy that. But on reflection, where does the raisin get the energy from to keep moving? Or any other orbiting body for that matter?

It's witchcraft.

[BorkBorkBork]

Simpo Two said:

cacbyname said:

Assuming the orange weighs 200g, I think at 2ft the raisin would take 66.9hours to orbit the orange.

I'll buy that. But on reflection, where does the raisin get the energy from to keep moving? Or any other orbiting body for that matter?

It's witchcraft.

Mass = energy. Gravity warps space time. Although, we have to ask if gravity really does exist? The rate of change is the thing that makes an object fall towards another. The closer you are to a massive object, the slower the rate of change (time), and therefore the orbiting object is pulled toward the massive object because the rate of change will apply differently across the object, making the part of it which is closer to the massive object change more slowly than the rest of it.

Again, I like to use a computer’s cpu as an analogy. The cpu has a finite capacity to process information. It can only do so many millions of calculations per second. In this analogy mass/energy = information. The more information, the longer it takes to process that information. Hence, the rate of change slows where mass/energy are concentrated.

[deckster]

Simpo Two said:

I'll buy that. But on reflection, where does the raisin get the energy from to keep moving? Or any other orbiting body for that matter?

It's witchcraft.

Gravity. Technically, something which is orbiting is continually falling down, it's just going at the right speed that it misses the object it's orbiting by the right amount to keep it falling all the way round. If it's going too fast, it misses the object by enough that gravity can't keep it there. If it's going too slow, it won't miss the object at all and will crash into it. But if it's going the right speed, the gravitational attraction will keep pulling it down at just the right rate so that it keeps missing the object for a very long time indeed.

Simpo Two said:

It's witchcraft.

Also, this.

[Dr Jekyll]

Simpo Two said:

I'll buy that. But on reflection, where does the raisin get the energy from to keep moving? Or any other orbiting body for that matter?

It's witchcraft.

It doesn't need energy to keep moving in a vacuum, only to accelerate or decelerate. Orbits only decay because there is a bit of atmosphere up there.

[annodomini2]

BorkBorkBork said:

Simpo Two said:

cacbyname said:

Assuming the orange weighs 200g, I think at 2ft the raisin would take 66.9hours to orbit the orange.

I'll buy that. But on reflection, where does the raisin get the energy from to keep moving? Or any other orbiting body for that matter?

It's witchcraft.

Mass = energy. Gravity warps space time. Although, we have to ask if gravity really does exist? The rate of change is the thing that makes an object fall towards another. The closer you are to a massive object, the slower the rate of change (time), and therefore the orbiting object is pulled toward the massive object because the rate of change will apply differently across the object, making the part of it which is closer to the massive object change more slowly than the rest of it.

Again, I like to use a computer’s cpu as an analogy. The cpu has a finite capacity to process information. It can only do so many millions of calculations per second. In this analogy mass/energy = information. The more information, the longer it takes to process that information. Hence, the rate of change slows where mass/energy are concentrated.

Mass warps spacetime, Gravity is an effect due to the warpage of space-time.

[BorkBorkBork]

annodomini2 said:

BorkBorkBork said:

Simpo Two said:

cacbyname said:

Assuming the orange weighs 200g, I think at 2ft the raisin would take 66.9hours to orbit the orange.

I'll buy that. But on reflection, where does the raisin get the energy from to keep moving? Or any other orbiting body for that matter?

It's witchcraft.

Mass = energy. Gravity warps space time. Although, we have to ask if gravity really does exist? The rate of change is the thing that makes an object fall towards another. The closer you are to a massive object, the slower the rate of change (time), and therefore the orbiting object is pulled toward the massive object because the rate of change will apply differently across the object, making the part of it which is closer to the massive object change more slowly than the rest of it.

Again, I like to use a computer’s cpu as an analogy. The cpu has a finite capacity to process information. It can only do so many millions of calculations per second. In this analogy mass/energy = information. The more information, the longer it takes to process that information. Hence, the rate of change slows where mass/energy are concentrated.

Mass warps spacetime, Gravity is an effect due to the warpage of space-time.

Agreed on the first bit. My mistake. On the 2nd bit I would argue gravity doesn’t exist at all, even as an effect. And I’d say the same about time.

Both time and gravity are human constructs to measure/explain the rate of change. I think it’s far simpler to just think about the rate of change and how that is affected by mass/energy.

It all comes back to the processing of information for me. The universe is one huge information processor.

[Fusion777]

Simpo Two said:

I'll buy that. But on reflection, where does the raisin get the energy from to keep moving? Or any other orbiting body for that matter?

It's witchcraft.

In terms of gravitation attraction- potential energy, which is converted to kinetic energy. Same as dropping something from height. No energy is needed to keep it moving in orbit, because there's no friction acting on it.