Scientific 'things you've always wanted to know' thread

[carmonk]

R300will said:

plasticpig said:

AshVX220 said:

So, if Gravity travels at C'ish. The guys at CERN think they have a particle that travels faster than C.

Could this be the begginings of an Anti-Gravity system? And if an Anti Grqavity System were created would it therefore enable travel across vast distances (eg - 1000LY) in a more acceptable time frame (1 month). Considering that it is negating the effect of the force which actually holds the entire Universe together?

They would need to discover a particle with negative mass for true anti gravity. It's something that has been treated quite seriously as a future potential propulsion system by NASA and is called a Diametric drive.

so any anti matter particle would do then?

Anti-matter weighs the same as normal matter, it's just the opposite charge.

[LordGrover]

Getragdogleg said:

A slightly light hearted question that arises from a question asked by a friendsyoung daughter:

"if you can get torches to shine light in a dark place why can't you get a torch that can shine dark into light places"?

Said mate was flummoxed for an answer.

This is because torches are in fact dark suckers; they suck up the dark leaving the light unimpeded.

[navier_stokes]

carmonk said:

R300will said:

carmonk said:

Zad said:

To be totally out of the earth's gravity is impossible.

[pedantic mode on]Actually most things are completely outside of the earth's gravity. Only that stuff that's in a 4.5bn light year radius of earth is affected by Earth's gravity[/pedantic mode off]

No its not like that. Gravitational forces affect every atom across the whole of the universe as their necessary protons neutrons and electrons were all created at the same time basically. So it doesn't matter how far apart they are as they have all existed for the same time so gravity links all of them. There was a good poem my physics teacher told us and it included the line 'you can not move a flower without troubling a star' And it's right.

That's absolutely not true. It sounds like you're talking about entanglement which is nothing to do with gravity and transmits no information. Gravity, to the best of our knowledge, cannot propogate faster than light.

No-one knows what gravity is so how do you know it has to "transmit" information? Only particles with mass cannot travel faster than light... but does gravity have mass?!

Any two objects that have mass will exert gravitational forces on each other - to our knowledge, over an infinite distance. I.e. any object in the universe will feel the gravitational field of the Earth

[carmonk]

navier_stokes said:

No-one knows what gravity is so how do you know it has to "transmit" information? Only particles with mass cannot travel faster than light... but does gravity have mass?!

Not true. Nothing can break the light barrier, mass or no mass. Gravity is information because should you detect it, it will give you information as to its origins.

navier_stokes said:

Any two objects that have mass will exert gravitational forces on each other - to our knowledge, over an infinite distance. I.e. any object in the universe will feel the gravitational field of the Earth

No it won't, I've just explained this.

[R300will]

carmonk said:

navier_stokes said:

No-one knows what gravity is so how do you know it has to "transmit" information? Only particles with mass cannot travel faster than light... but does gravity have mass?!

Not true. Nothing can break the light barrier, mass or no mass. Gravity is information because should you detect it, it will give you information as to its origins.

navier_stokes said:

Any two objects that have mass will exert gravitational forces on each other - to our knowledge, over an infinite distance. I.e. any object in the universe will feel the gravitational field of the Earth

No it won't, I've just explained this.

yes it will. i explained it and have the backing of a friend studying physics at oxford as well. Also nothing can break the light barrier as far as we know.

[carmonk]

R300will said:

yes it will. i explained it and have the backing of a friend studying physics at oxford as well. Also nothing can break the light barrier as far as we know.

I honestly don't know what you're talking about. Either you believe gravity can travel instantaneously (which nobody else does) or you don't believe what you've just written.

[R300will]

carmonk said:

R300will said:

yes it will. i explained it and have the backing of a friend studying physics at oxford as well. Also nothing can break the light barrier as far as we know.

I honestly don't know what you're talking about. Either you believe gravity can travel instantaneously (which nobody else does) or you don't believe what you've just written.

When everything gained mass during the big bang, which wasn't long after the start, the field and therefore force of gravity was also created. All of the atoms experienced each others gravity and even though they are far apart now the field and forces were already established so they still feel each other. e.g. The earth feels the gravity of other stars in its galaxy but they are all in equilibrium around the black hole in the centre so nothing becomes of it. Same for every other atom, planet, etc in the universe.

[carmonk]

R300will said:

carmonk said:

R300will said:

yes it will. i explained it and have the backing of a friend studying physics at oxford as well. Also nothing can break the light barrier as far as we know.

I honestly don't know what you're talking about. Either you believe gravity can travel instantaneously (which nobody else does) or you don't believe what you've just written.

When everything gained mass during the big bang, which wasn't long after the start, the field and therefore force of gravity was also created. All of the atoms experienced each others gravity and even though they are far apart now the field and forces were already established so they still feel each other. e.g. The earth feels the gravity of other stars in its galaxy but they are all in equilibrium around the black hole in the centre so nothing becomes of it. Same for every other atom, planet, etc in the universe.

But that's not the same thing, for the four reasons I've already described.

1) Gravity due to an object cannot occur before that object has been created. So the gravitational pull of the earth could not have existed before the earth was created, regardless of all its particles coming from the big bang. You can't equate the gravitational force of disparate particles with the gravitational force of an object comprising those particles.

2) When the universe first expanded it did so faster than light. It's by no means clear that gravity also expanded to keep up and all indications are that it didn't, or that the question has no meaning.

3) Gravity, as we've established, can only travel at light speed. So if an object was created X years ago it can only affect objects within X light years of it.

4) Distant galaxies are moving away from us faster than light. That means whatever change we make here it will never be reflected in those galaxies. Therefore clearly the earth and those galaxies are not connected by gravity. If you think otherwise then describe an experiment to prove it.

Edited by carmonk on Thursday 19th January 20:13

[Hooli]

NismoGT said:

Why are the four inner planets of the Solar System made of Rocky/Silicate/metallic material.

And the outer 4 giants made mostly of gas?

I don't understand why this is. The solar system was created from the same dusty/gas nebula.

Proximity to the sun? Or relating to the sun's gravity in any way?

Yup gravity. As I understand it the heavy things (ie rocks) fell further towards the sun & the lighter gasses stayed further out.

[R300will]

carmonk said:

But that's not the same thing, for the four reasons I've already described.

1) Gravity due to an object cannot occur before that object has been created. So the gravitational pull of the earth could not have existed before the earth was created, regardless of all its particles coming from the big bang. You can't equate the gravitational force of disparate particles with the gravitational force of an object comprising those particles.

2) When the universe first expanded it did so faster than light. It's by no means clear that gravity also expanded to keep up and all indications are that it didn't, or that the question has no meaning.

3) Gravity, as we've established, can only travel at light speed. So if an object was created X years ago it can only affect objects within X light years of it.

4) Distant galaxies are moving away from us faster than light. That means whatever change we make here it will never be reflected in those galaxies. Therefore clearly the earth and those galaxies are not connected by gravity. If you think otherwise then describe an experiment to prove it.




And whatever speed gravity is it must be faster than this fking site

Edited by carmonk on Thursday 19th January 20:16

Is it proven that the gravitational field can't extend faster than the speed of light?

If Galaxies are moving away form us faster than light how can we work that out? I understand they are moving away due to the red shift in their spectrums. But how do you detect their speed past the speed of light?

Yes gravity due to an object cannot be felt until it exists but the atoms that make up the object can. You are merely concentrating the gravity of these atoms together causing a more noticeable effect in space time.

[Hooli]

R300will said:

If Galaxies are moving away form us faster than light how can we work that out? I understand they are moving away due to the red shift in their spectrums. But how do you detect their speed past the speed of light?

As I understand it the galaxies are going slower than the speed of light but space is also moving away from us. It's a bit like a car driving away at 50mph but on a conveyor belt that is also travelling away at 50mph. The car is doing 50mph but travelling away at 100mph (no idea if it takes off though).

[carmonk]

R300will said:

Is it proven that the gravitational field can't extend faster than the speed of light?

It's been measured as such so there's no evidence that it can.

R300will said:

If Galaxies are moving away form us faster than light how can we work that out? I understand they are moving away due to the red shift in their spectrums. But how do you detect their speed past the speed of light?

No idea about that, it's just what I read. I'm only using it as an illustration of a situation where gravity isn't and can't be felt from Earth.

R300will said:

Yes gravity due to an object cannot be felt until it exists but the atoms that make up the object can. You are merely concentrating the gravity of these atoms together causing a more noticeable effect in space time.

But gravity isn't just an elastic band you attach and it's there for ever, it's a quantifiable distortion of spacetime by mass. If you have particles arranged

A - B - C

and then you group together C and A to get

AC - B

then clearly the gravitation effect on B is different.

To demonstrate connection you have to show how it might work. So if you say right, the Earth is connected gravitationally to planet X which is 30bn light years away you have to be able to show how we could prove that. Even ignoring that planet X is travelling away from us, current physics tells us that if you make a change to Earth's mass then planet X will not register that change in gravity for 30bn years. Which is pushing my definition of connection if not yours. If tomorrow we create a supermassive black hole somewhere near the moon then it is simply wrong to say the gravitational effects connect it to the rest of the universe. For hundreds of billions of years most of the universe will carry on just as it has before as the effects of gravity propogate out at what amounts to a crawl. The fact that the black hole is comprised of pre-existing particles isn't relevant.

[MiniMan64]

Getragdogleg said:

A slightly light hearted question that arises from a question asked by a friendsyoung daughter:

"if you can get torches to shine light in a dark place why can't you get a torch that can shine dark into light places"?

Said mate was flummoxed for an answer.

You can.

It's called a shadow.

[R300will]

carmonk said:

To demonstrate connection you have to show how it might work. So if you say right, the Earth is connected gravitationally to planet X which is 30bn light years away you have to be able to show how we could prove that. Even ignoring that planet X is travelling away from us, current physics tells us that if you make a change to Earth's mass then planet X will not register that change in gravity for 30bn years. Which is pushing my definition of connection if not yours. If tomorrow we create a supermassive black hole somewhere near the moon then it is simply wrong to say the gravitational effects connect it to the rest of the universe. For hundreds of billions of years most of the universe will carry on just as it has before as the effects of gravity propogate out at what amounts to a crawl. The fact that the black hole is comprised of pre-existing particles isn't relevant.

Given that gravity bends the fabric of space time which is like a net according to einstein then the severe distortion due to a supermassive black hole will quickly spread across the fabric will it not?

You could also suggest that quantum theory states that electrons cannot be in the same spin and plane as any others throughout the universe. So by heating something up you are changing the electrons state and therefore shifting all of the others throughout the universe, so gravity could work in the same way in terms of linkage? This isn't from oxford friend this is me letting my mind go nuts on quantum theory

[carmonk]

R300will said:

Given that gravity bends the fabric of space time which is like a net according to einstein then the severe distortion due to a supermassive black hole will quickly spread across the fabric will it not?

Quick for us, very slow as far as the universe is concerned. Even if the universe wasn't expanding it would take 60 or 70bn years to even affect half of it.

R300will said:

You could also suggest that quantum theory states that electrons cannot be in the same spin and plane as any others throughout the universe. So by heating something up you are changing the electrons state and therefore shifting all of the others throughout the universe, so gravity could work in the same way in terms of linkage? This isn't from oxford friend this is me letting my mind go nuts on quantum theory

Not sure I've heard that one, but I think it wouldn't be the same as communicating information as you wouldn't know the spin without measuring it in the first place, a bit like entanglement which also doesn't transmit anything faster than light.

[MiniMan64]

PW said:

Hooli said:

NismoGT said:

Why are the four inner planets of the Solar System made of Rocky/Silicate/metallic material.

And the outer 4 giants made mostly of gas?

I don't understand why this is. The solar system was created from the same dusty/gas nebula.

Proximity to the sun? Or relating to the sun's gravity in any way?

Yup gravity. As I understand it the heavy things (ie rocks) fell further towards the sun & the lighter gasses stayed further out.

That theory ignores the fact that a large number of exoplanets found so far are large gas giants with orbits smaller than Mercury...

In fact your point rather renders the question mute anyway.

Yes in our solar system that layout is the case with smaller inside and large gas giants outside but I think we're starting to see that solar systems can take any shape, form or layout and there's not really a fixed plan or "order" for different types of planets. Therefore there's no need for a theory of why certain planets always orbit in a certain place because in reality, they don't.

[Einion Yrth]

PW said:

That theory ignores the fact that a large number of exoplanets found so far are large gas giants with orbits smaller than Mercury...

We've found those because they happen to be of a kind that is easy(ish) to detect. We don't have a large enough sample yet to draw any conclusion as to whether or not they are common or abnormal.

[R300will]

carmonk said:

R300will said:

Given that gravity bends the fabric of space time which is like a net according to einstein then the severe distortion due to a supermassive black hole will quickly spread across the fabric will it not?

Quick for us, very slow as far as the universe is concerned. Even if the universe wasn't expanding it would take 60 or 70bn years to even affect half of it.

R300will said:

You could also suggest that quantum theory states that electrons cannot be in the same spin and plane as any others throughout the universe. So by heating something up you are changing the electrons state and therefore shifting all of the others throughout the universe, so gravity could work in the same way in terms of linkage? This isn't from oxford friend this is me letting my mind go nuts on quantum theory

Not sure I've heard that one, but I think it wouldn't be the same as communicating information as you wouldn't know the spin without measuring it in the first place, a bit like entanglement which also doesn't transmit anything faster than light.

But you wouldn't need to know the spin because, as far as the theory states, any electron cannot be in the same state of spin as another throughout the universe so the transmission should therefore be instantaneous like if they were all connected by something. So basically if you join something to something else with a big metal bar, no matter how far away it is from the original thing you can still immdeiately alter the position of one by manipulating the other, i am suggesting that gravity works in the same way between the atoms of the early universe and that no matter how far they are now they can still be manipulated using this method.

As for gravity travelling faster than the speed of light i don't know but i would assume that it has already 'spread' past the observable universe as we can see clear stars and galaxies etc at the edge of it, which is as fast as the light can travel to us.

[Einion Yrth]

R300will said:

So basically if you join something to something else with a big metal bar, no matter how far away it is from the original thing you can still immdeiately alter the position of one by manipulating the other,

This is incorrect. The speed of transmission of that effect is the speed of sound in your metal bar. Significantly < C

[R300will]

Einion Yrth said:

R300will said:

So basically if you join something to something else with a big metal bar, no matter how far away it is from the original thing you can still immdeiately alter the position of one by manipulating the other,

This is incorrect. The speed of transmission of that effect is the speed of sound in your metal bar. Significantly < C

No. You are not transmitting sound you are moving molecules all linked by strong covalent bonds. They will not separate easilly, try pulling a steel bar apart? that was my line of thought.