Thread: Size = Mass / Energy

1. It's a crude equation but it explains the idea well enough ..

Expanding Earth Theory (missing mass resolved) - YouTube

Here is quick overview.

I had this thought, if there is a rough equation that determines the size of a massive object, what would that equation involve. My first thought was, all that determines size is the amount of matter or mass. But then I know that energy and mass are related because e=mc2, therefore I thought that size might be related to mass and energy. I figured black holes get really small and take up an almost infinitely small amount of space and we know that black holes have massive amounts of energy as they are what hold galaxies together.

So I got ..

A small size (s) = mass?(m) and lots of energy(e)

The only unknown element there is mass and the only way I can get (s) to be a small number and allow (e) to remain huge is to divide it by a small amount of (m).

0.001 = 1 / 1000

This then got me thinking about the expanding Earth video on youtube which I thought there might be something in but no one could explain where the mass comes from. I had the idea that it's not a matter of increased mass, it's a matter of decreased energy.

To begin with Earth is ..

10s = 50m / 5e

If energy is decreased to 2.5

20s = 50m / 2.5e

Please watch the video if this interests you as it explains it much better than this. Also 17.22 onward is about plate techtonics which doesn't sit well with me and never has, so you don't need to watch that bit if you don't want to.

2.

3. Could you write a brief synopsis please? For the benefit of those who don't have 25 minutes to watch your linked video.

4. Watched to a couple of minutes in. I'm afraid your ideas simply don't fit in with the known law of physics.

Mass and energy are essentially the same thing, and are linked by Einstein's equation E=mc^2. That is to say, 1 kg of mass and ~300 MJ of energy are exactly equivelent.

'Size', by which I assume you mean volume, does not depend on mass, which is why the same volume of water and iron do not weigh the same.

5. Originally Posted by RichA12
It's a crude equation but it explains the idea well enough ..
it would actually be quite nice if you summarise the gist in a few paragraphs
as drowsy turtle implied, if i'm going to sit through a 25 minute video, i don't want to end up with the feeling that they're 25 minutes wasted

6. Please try to forget about everyday physics, sure they still apply for massive objects but also, gravity or space time distortion also becomes part of the equation.

Yes, I struggle a bit with mass and energy being said to be the same thing. However there is conservation of matter or mass when energy has disipated. For example a stone weighs 1kg at 20'C. At 1000'C it weighs maybe 1.000000000001kg and as it cools it does not loose mass so therefore it's possible to loose energy whilst conserving mass. In relation to the loss of energy, 1000'C to 20'C, the amount of mass lost is insignificant.

7. OK I have edited my first post to give an overview however the video is better at explaining the idea.

8. Originally Posted by RichA12
Please try to forget about everyday physics, sure they still apply for massive objects but also, gravity or space time distortion also becomes part of the equation.
It doesn't matter. At relativistic speeds, and on quantum scales, mass and energy are both conserved.

Originally Posted by RichA12
Yes, I struggle a bit with mass and energy being said to be the same thing. However there is conservation of matter or mass when energy has disipated. For example a stone weights 1kg at 20'C. At 1000'C it weighs maybe 1.000000000001kg and as it cools it does not loose mass so therefore it's possible to loose energy whilst conserving mass. In relation to the loss of energy, 1000'C to 20'C, the amount of mass lost is insignificant.
The amount of mass lost is small, but real. In cooling from 1000 C to 20 C, and assuming a specific heat of around 2 kJ/kg/k, roughly 1.96 MJ will be lost in energy, which is roughly 6.5g.

9. That's cool, but 6.5g is only a 0.0065% reduction in mass from 1kg and yet 20'C is a 5000% decrease in energy from 1000'C.

10. Originally Posted by RichA12
20'C is a 5000% decrease in energy from 1000'C.
That is temperature not energy.

And taking ratios of centigrade temperatures is meaningless.

11. Originally Posted by RichA12
I thought that size might be related to mass and energy
It is. But not in the way you think. The key word here is "density".

I figured black holes get really small and take up an almost infinitely small amount of space and we know that black holes have massive amounts of energy as they are what hold galaxies together.
They have exactly the same amount of energy (=mass) as the material they formed from; they don't magically get more energy because they become black holes.

And they don't hold galaxies together (they may play a role in their formation...)

Also the last third is about plate techtonics which doesn't sit well with me and never has
I assume that is just because you don't understand it?

12. Something hot has more energy than something cold doesn't it?

Well with regards to black holes, the only way the idea stands up is if black holes turn mass into energy.

Energy and mass affect density don't they? Density is related to pressure and energy and mass relate to gravity which is a form of pressure.

I understand plate techtonics very well, the problem is I find way too many holes in it. The last part of my video describes those holes from 17.22 onwards.

13. This is going to pseudoscience.

14. No it's simple science, surely someone get's the logic of it? It's just that the nature of physics changes with scale, it's impossible to talk about and experiment with gravity when we are currently unable to manipulate it. All physics take place where there is a constant gravity, surely changing gravity changes our everyday physics.

Take the hot stone idea and scale it up to the size of Earth. As it cools down and looses energy and yet retains 99% of it's mass, gravity will decrease because mass and energy create gravity. With decreased gravity the mass and remaining energy is more easily able to occupy more space and if there is nothing stopping it from occupying more space for example a thick crust, then it will occupy the space that is all ready predetermined by the impression or lack of impression on the fabric of space time.

15. Lol moved from Earth science board, in 10 years from this will be common Earth science. You don't think this relates to Earth science, am quite offended. Is Earth science all about agreeing with what we believe to be true Earth science? Is that what science is, I thought science was the pursuit of truth and not about belief in a common agreement, that sounds more like religion?

This is not a great analogy but take a fat man and a little child and place them in the center of a trampoline, not at the same time - one after the other. They must stand with their feet one foot apart. This is also a very special trampoline because it's very flexible and has a lot of space under it, it can sag as far as 100 meters if the weight is big enough.

The question is, which person will have more problems keeping their feet one foot apart? The fat man or the little child? The answer is obviously the fat man. He is much heavier therefore causes the trampoline to stretch down by 20 meters and so his feet naturally want to come together and in fact the force may prevent him from keeping his feet one foot apart and might cause his feet to slam together and then there will no chance of seperating them again (also they will be occupying less space). The child on the other hand is very light and makes the tampoline stretch down by only a meter, she has no problems keeping her feet one foot apart.

16. Originally Posted by RichA12
Something hot has more energy than something cold doesn't it?
Apparently not:
Originally Posted by RichA12
You can't pick and choose which bits of science are right because they support your idea and which bits are wrong because they don't fit with your version of reality.

17. Well it's just a thought, don't give it any more thought if it means nothing to you or you're unable to think about it! It's no big deal!

18. Lol moved from Earth science board, in 10 years from this will be common Earth science
Perhaps in some strange apocalyptic pseudoscience world....perhaps....

19. Originally Posted by RichA12
Lol moved from Earth science board, in 10 years from this will be common Earth science. You don't think this relates to Earth science, am quite offended. Is Earth science all about agreeing with what we believe to be true Earth science? Is that what science is, I thought science was the pursuit of truth and not about belief in a common agreement, that sounds more like religion?
Science is about making observations, coming up with a hypothesis to explain the observed phenomena, then testing your hypothesis with experimentation. You have done none of that. You wrote down a few numbers on a pad of paper with no explanation. What makes you think "mass divided by energy = space"? Is there experimental justification for that?

This is not a great analogy but take a fat man and a little child and place them in the center of a trampoline, not at the same time - one after the other. They must stand with their feet one foot apart. This is also a very special trampoline because it's very flexible and has a lot of space under it, it can sag as far as 100 meters if the weight is big enough.

The question is, which person will have more problems keeping their feet one foot apart? The fat man or the little child? The answer is obviously the fat man. He is much heavier therefore causes the trampoline to stretch down by 20 meters and so his feet naturally want to come together and in fact the force may prevent him from keeping his feet one foot apart and might cause his feet to slam together and then there will no chance of seperating them again (also they will be occupying less space). The child on the other hand is very light and makes the tampoline stretch down by only a meter, she has no problems keeping her feet one foot apart.
All of that is explained by plain old Newtonian mechanics - force, mass, acceleration due to gravity, coefficients of elasticity, etc. You should go to school and learn about these things. It's very interesting. What does this trampoline business have to do with your hypothesis? What even is your hypothesis?

By the way, Rich. The next time you make a video, think about what you want to say before you start the camera running. Nobody wants to sit there watching you mumble, hem and haw while you try figure out what you want to say. No one has time for that.

20. Sometimes you cannot test hypothesis without the development of a particular technology. Don't tell me what science is, modern science is about adhering strictly to scientific belief akin to religion or about surpressing scientific information for commerical gain. Was hoping for intellectual discussion here with some bright people but I guess that isn't going to happen.

Also, are you only interested in science that has already been tested and concluded? You're not interested in hypothesis only? Sounds like you want all the answers given to you on a plate without applying any effort at all i.e. lazy.

The trampoline example is to describe the pressure that space time puts on an object which in return affects it's size or the space in which it occupies. Forget it, this is just a hobby for me, I thought some in the profession might be interested in the idea but I really couldn't give a damn.

21. Originally Posted by RichA12
Don't tell me what science is, modern science is about adhering strictly to scientific belief akin to religion or about surpressing scientific information for commerical gain.
Of course it isn't. Look at any science journal and you will see new ideas being proposed and old ideas being repeatedly challenged and tested.

22. There is some good science, of course there is or we wouldn't have the technologies we currently have. But there is a lot of bad science too, again this is akin to religion - good and bad.

Anyway, I don't have time to test, I am not able to test, no one on Earth is able to test this theory. It would take a more qualified mind than mine to take it any where but of course I am interested in what anyone has to say on the matter.

Any by the way, there are no prerequisites for a hypothesis - sure a hypothesis may be based or influenced by existing science but essentially a new hypothesis is a new idea and nothing more is needed to form a hypothesis.

23. Originally Posted by RichA12
But there is a lot of bad science too, again this is akin to religion - good and bad.
Such as?

Any by the way, there are no prerequisites for a hypothesis
Well, you normally need a reason for a new hypothesis. New observations which aren't explained by current theory, for example.

If you are just making up ideas with no basis, then I would call that speculation rather than hypothesis.

24. My observations are the holes in plate techonics. All you're interested in is looking for holes or in trying to thwart my idea without even thinking about it. Forget it, you are only interested in adhering to your current beliefs - amen to that.

25. Originally Posted by RichA12
My observations are the holes in plate techonics.
What do you see as the holes in plate tectonics? (not an area I have any great expertise in, but I would be interested to hear more)

All you're interested in is looking for holes or in trying to thwart my idea without even thinking about it.
Of course I am going to test your idea and look for holes in it. That is how science works. All new ideas are vigorously attacked to see if they survive:
Originally Posted by Peter Watts
This is how it works: you put your model out there in the coliseum, and a bunch of guys in white coats kick the shit out of it. If it’s still alive when the dust clears, your brainchild receives conditional acceptance. It does not get rejected. This time.
On the face of it, your proposal doesn't seem to match any aspect of standard physics. You must therefore expect it to be questioned.

If you just want people to accept what you say without questioning it (like a religion) then you have come to the wrong place.

26. Watch video from 17.22 onwards for holes in techtonics. Also have been having this discussion Subduction - Science Forums

What is so complicated about energy affecting gravity and in turn gravity affecting size?

27. Originally Posted by RichA12
Take the hot stone idea and scale it up to the size of Earth. As it cools down and looses energy and yet retains 99% of it's mass, gravity will decrease because mass and energy create gravity. With decreased gravity the mass and remaining energy is more easily able to occupy more space and if there is nothing stopping it from occupying more space for example a thick crust, then it will occupy the space that is all ready predetermined by the impression or lack of impression on the fabric of space time.
It's a nice thought. But as we've already established, the amount of mass lost is negligible (and a lot of it goes on to drive chemical changes, rather than being lost), and the Earth isn't an isolated system. To test this hypothesis, then, we need real evidence. Now, given that we know that heating an object causes it to expand, and allowing it to cool causes it to contract, and given that we know from geological structures such as cooling joints that the same is true of the material comprising the Earth itself, we can logically conclude that the Earth should get smaller when it cools, not bigger.

Are you willing to accept that?

28. Originally Posted by RichA12
Watch video from 17.22 onwards for holes in techtonics.
Sorry, can't watch YouTube. (And probably wouldn't on principle)

29. Originally Posted by drowsy turtle
It's a nice thought. But as we've already established, the amount of mass lost is negligible (and a lot of it goes on to drive chemical changes, rather than being lost), and the Earth isn't an isolated system. To test this hypothesis, then, we need real evidence. Now, given that we know that heating an object causes it to expand, and allowing it to cool causes it to contract, and given that we know from geological structures such as cooling joints that the same is true of the material comprising the Earth itself, we can logically conclude that the Earth should get smaller when it cools, not bigger.

Are you willing to accept that?
Those physics still apply, of course atoms take up more space as they get hotter. However if another force, namely gravity, changes then it must become part of the equation. Also when we heat something up here on Earth there are external pressures affecting it's shape or size, we can make things in any shape or size. If we could heat the Earth up, sure there may be some normal expansion like we would expect but it would be insignificant in relation to the affect the energy would have on gravity or fabric of space time.

You cannot talk about gravity without talking about energy AND mass. Heat is energy.

30. Originally Posted by Strange
Originally Posted by RichA12
But there is a lot of bad science too, again this is akin to religion - good and bad.
Such as?
By the way, it would be rather ironic if you think that plate tectonics is one of these "religiously" adhered to theories. It took decades for enough evidence to accumulate to convince people. I remember seeing a documentary when I was young with people presenting this crazy new idea and lots of geologists being interviewed saying it was obviously nonsense. The theory is still being developed and worked on. As far as I know (which isn't an awful lot, as I say) all the new evidence is still consistent with it.

Could you summarize your main issues with the theory?

31. Originally Posted by RichA12
If we could heat the Earth up, sure there may be some normal expansion like we would expect but it would be insignificant in relation to the affect the energy would have on gravity or fabric of space time.
Can you quantify that? What would be the increase in gravity and what effect would it have on the size of the earth?

32. Well that's a good question Strange. I think it may be quantifiable but the maths is beyond me hence I only came up with s=m/e. Am really not sure, if energy is increased 10x, does that increase gravity 10x? I'm really not sure but I've not doubt it could be reverse engineered to form practicle equations. I did try to create equation to equate diamter using mass and energy but the closest I could get the moon to be was 1400km in diameter which is only half it's diameter. Also it's never going to be that accurate as it's impossible to say how much of an affect the matter is having, there may be a thick crust, there me be no core and porous matter or not very dense matter.

So it serves no practical purpose but I have feeling that it might change some other things and in turn serve a practical use.

The effect of increasing energy on Earth would be increased gravity which would cause the Earth to want to collapse inwards and become smaller, in short it would have horrific consequences and we really would have different parts of the crust colliding with each other.

More importantly though, ask yourself what would happen if Earth lost energy baring in mind that the Earth was at one time encased in a solid crust?

33. Why can't you watch youtube videos Strange?

34. Originally Posted by RichA12
Why can't you watch youtube videos Strange?
Lack of appropriate technology, company firewall, and lack of patience with the medium. I did make an effort to access and start watching Richard Feynman's QED lectures (which are very good) but after about 10 minutes decided to read the book instead.

Why can't people write their ideas down any more! I get very frustrated when new products only provide videos instead of user manuals - how are you supposed to look anything up...

35. Watch it when you get home however you can probably get a picture for it youself if you think about it. The reason Earth looses energy is because there are a few small cracks and volcanoes leaking heat energy over a long period of time through the thick crust. This causes decreased gravity which means there is an outward pressure, eventually there is a violent crack which forms basis for our fault lines in the oceans. More energy is lost through fault lines, Earth begins to expand. Eventually it stops because an equilibrium is reached and it won't collapse unless energy is somehow increased which is kind of impossible without totally destroying the Earth.

36. A quick google suggest the current loss of heat from the earth is about 46 TW.

Over 1 year this is about 1.5 x 1021 joules or 16,000kg.

Over the lifetime of the earth this is about 6.5x1013 kg (type 46 terawatts * 4e9 year / c^2 in kg into google).

That sounds like quite a lot. But what fraction of the earth's mass is this? 10-11 (type 6.5e13 kg / mass of earth into google)

Obviously the earth was a lot hotter in the past and would have radiated more energy. I don't know what the appropriate figures are (research project for you) but lets say that on average it was 1,000 times more than the above (which is a gross exaggeration I'm sure). Then the total loss of mass-energy would have reduced the mass of the earth (and hence gravity) by one millionth of one percent. Doesn't sound too significant to me.

That should give you a start at working out something more realistic.

37. No because you're saying that only mass determines gravity. In actual fact, I believe energy has more of an affect on gravity than does mass. That's not to say that mass is less affected by gravity, we know that mass is very much affected by gravity simply by dropping something.

Early on when Earth was just a fireball with a thick crust and no atmosphere, it wouuld have lost considerbly more energy than it does currently where we see an insulating atmosphere.

38. Originally Posted by RichA12
No because you're saying that only mass determines gravity. In actual fact, I believe energy has more of an affect on gravity than does mass.
No. Mass and energy have exactly the same gravitational effect.

39. OK so why doesn't energy have much of an affect on mass? Going back to hot stone, reducing energy by 5000% decreases mass by only 0.0001% or whatever. They are not entirely intertwined.

40. Originally Posted by RichA12
OK so why doesn't energy have much of an affect on mass? Going back to hot stone, reducing energy by 5000% decreases mass by only 0.0001% or whatever. They are not entirely intertwined.
I'm not sure what you mean. Energy and mass have an exactly equivalent effect. But remember that they are related by e=mc2 and c2 is a very large number so you need a huge amount of energy to have a noticeable effect.

41. Right, so what is the formula for gravity in relation to e=mc2?

42. Lets take a specific example. 1kg of water (specific heat ~4 J g-1 K-1). To raise its temperate by 1000 degrees requires 4 million joules. This is equivalent to 10-11 kg.

So you have increased the gravitational effect of the water by 1.00000000001.

I think you need to do a few basic calculations like this yourself to see whether you idea is credible.

43. Originally Posted by RichA12
Right, so what is the formula for gravity in relation to e=mc2?

Acceleration due to gravity is or

That is an approximation for normal scales; if you get to extreme values you would need to use the math of general relativity.

44. Nope you have increased it's mass which means it is more affected by Earth's gravity well.

I am talking about manipulation of or affecting gravity wells. What is the formula which tells me how much gravity an object has based on how much energy AND mass it has?

45. Originally Posted by RichA12
Nope you have increased it's mass which means it is more affected by Earth's gravity well.
Same thing: its increased pull on the earth is exactly the same as earth's increased pull on it.

46. I edited my post, what is the formula which tells me how much gravity an object has based on how much energy AND mass it has? You cannot use radius or dimensions of any sort, just mass and energy.

47. What do you mean by "how much gravity" it has? (for example, what units does it have?)

The easy route is to use Newtonian gravity (converting the energy to mass), but that requires you to specify the distance.

Otherwise you are going to need something like this Stress-energy tensor

48. Sure, there isn't one however energy and mass are the only things which affect the fabric of space time and the only things that create gravity.

49. So what's my point I hear you ask, well if I cannot determine gravity from mass and energy only, I cannot determine if energy affects gravity. The truth is, you cannot answer if energy affects gravity, not yet at least but judging by this hypothesis, it's pretty safe to assume it does.

50. There isn't one what?

The other things that affect gravity are pressure, energy flow, momentum flow and, of course, gravity itself. But to take those into account you need to use general relativity (and that is way beyond me).

51. Originally Posted by RichA12
So what's my point I hear you ask, well if I cannot determine gravity from mass and energy only, I cannot determine if energy affects gravity. The truth is, you cannot answer if energy affects gravity, not yet at least but judging by this theory, it's pretty safe to assume it does.
If you want to take distance out of the equation then you can caclulate

I haven't thought about what this represents but it is distance-independent (divide by r^2 to get acceleration; or multiply by the "other" mass and divede by r^2 to get force).

To put it more simply, the "gravity" of an object is simply proportional to its total mass+energy (but mass dominates because of the c^2 factor).

52. This is where I get lost ..

So G = (m + c/c2) ?

53. Originally Posted by RichA12
This is where I get lost ..

So G = (m + c/c2) ?
Not quite. G is the gravitational constant, which is the proportionality constant between mass and gravity. The proportionality constant between energy and gravity is G/c2.

So "something" (representing the gravity of an object) = G * m (for mass) or G * e/c2 (for energy) or G * (m + e/c2) for both.

You might as well just use (m + e/c2) though.

54. Aha! This "something" has a name. It is the Standard gravitational parameter. I learnt something new.

55. Right, well my hypothesis refutes the existance of this gravitational constant. I am talking else where about gravity, I paste in what I wrote.

To the space temperature thing, it's confusing me as it puts into question whether mass alone is enough to create gravity. If all of space was 1000'C would matter clump into massive spherical objects? If they do then mass alone can create gravity. If they don't then it proves that gravity is created by a contrast in energy.

We know that mass is easily affected by gravity simply by dropping something. But which affects gravity more, mass or energy? Maybe in the 1000'C space environment, an object would need to have 1000x more mass to create the same amount of gravity, because it's energy is only relative to the amount of energy surrounding it.

Also how can we test how much energy is affected by gravity? Maybe energy is hardly affected by gravity at all but it is easily manipulated by matter or mass, we cannot drop some energy. Weird science.

So to conclude, there is no gravitational constant, gravity is determined entirely by "relative energy" and mass.

56. Originally Posted by RichA12
Those physics still apply, of course atoms take up more space as they get hotter. However if another force, namely gravity, changes then it must become part of the equation. Also when we heat something up here on Earth there are external pressures affecting it's shape or size, we can make things in any shape or size.
We are, though, capable of building vacuum chambers.

Originally Posted by RichA12
If we could heat the Earth up, sure there may be some normal expansion like we would expect but it would be insignificant in relation to the affect the energy would have on gravity or fabric of space time.
Not actually true. As I keep explaining, the mass change due to the heating is negligible, so as a result the change in the gravitational field strength would be negligible - the change at the surface would be far, far less significant than the density contrast of, say, a metal pipe in the ground. It is also relevant that the Earth is cooling down and so thermally contracting, not expanding.

57. Well, if you now want to overthrow all of Newtonian physics and general relativity you have quite a job on your hands.

Originally Posted by RichA12
If all of space was 1000'C would matter clump into massive spherical objects?
Do you understand the relationship between temperature and energy?

How can "space" have a temperature? If you are talking about the interstellar material, then it is very diffuse and this represents a tiny amount of energy.

If they do then mass alone can create gravity. If they don't then it proves that gravity is created by a contrast in energy.
Both mass and energy cause gravity.

But which affects gravity more, mass or energy?
Both affect gravity equally (after you divide the energy by c2).

You really need to do some quantitative calculations to demonstrate the scale of the effect you are talking about.

58. I don't "want" to over through anything or anyone. The question is, does the hypothesis propose there being no gravitational constant and that's exactly what it does.

59. Well, your speculation does, but that means nothing. You can provide no scientific support for it, don't want to bother to do the math, or "go through it". Strange has been very patient with you, but it appears you want to dispose of a century of science, Copernican, Keplerian, Newtonian, and Enisteinian, with no math, and only because it's a great idea you have.

That's not how science works.

60. Originally Posted by RichA12
I don't "want" to over through anything or anyone. The question is, does the hypothesis propose there being no gravitational constant and that's exactly what it does.
Well, unfortunately, there is a gravitational constant. It is the constant that relates mass (and, through mass-energy equivalence, energy) to gravity. If you want to get rid of that, then you have to explain how we feel the force of gravity we do on earth, how the planets orbit the sun, gravitational lensing, and so on and so on.

Do you have a GPS system? Or something that depends on it like a mobile phone or bank account? These wouldn't work if gravity didn't work as we think it does.

61. Originally Posted by RichA12
I edited my post, what is the formula which tells me how much gravity an object has based on how much energy AND mass it has? You cannot use radius or dimensions of any sort, just mass and energy.
Well, this formula would be the Einstein Field Equations :

Size, radius and dimensions do not come into play here; the energy configurations are described by the stress-energy-momentum tensor T. This is in fact independent of any dimensions and sizes, since this tensor equation is invariant under coordinate transformations.

62. Well that looks great. This could easily be tested by creating a high relative energy difference (press a metal plate that's actively cooled to as close to 0K as possible against another plate that is actively heated as high as possible). In theory this ought to create a small gravity well within Earth's gravity well, it would require less effort or energy to move the whole apparatus up, left and right. Maybe just the push of a finger would send it out of Earth's orbit.

I know this is insane, I'm not looking for help with my sanity.

63. My basic question is if you could take all the energy out of a massive object (yes we know that it's mass would decrease fractionally which would fractionally decrease gravity, but ignore this), would taking all of the energy out of a massive object affect gravity?

I don't have much knowledge, I would like proper scientific explanation as to why energy does not apparently influence the fabric of time space.

64. Originally Posted by RichA12
My basic question is if you could take all the energy out of a massive object (yes we know that it's mass would decrease fractionally which would fractionally decrease gravity, but ignore this), would taking all of the energy out of a massive object affect gravity?
Yes it would. Similarly if you were to convert the mass of the earth into pure energy and (somehow) keep it inside a sphere the size of the earth, its gravity would be exactly the same.

I don't have much knowledge, I would like proper scientific explanation as to why energy does not apparently influence the fabric of time space.
It does. Mass and energy are equivalent. They both cause gravity (curve spacetime). Did you skip posts 35, 37, 39, 41, 42, 44, 49, 50, 52, 56, 59 and 60?

You can calculate the effect using the Einstein field equation (post #60) or (as a good approximation in normal circumstance; e.g. not near a black hole) using Newton's law of gravitation and mass-energy equivalence (e=mc2).

65. So can you tell me how much gravity there would be if all the energy was taken out of Earth? I am not interested in the affect energy has on mass, I am only interested in the affect energy has on gravity.

66. Originally Posted by RichA12
So can you tell me how much gravity there would be if all the energy was taken out of Earth?
What do you mean by "all the energy"? Do you just mean thermal energy (reducing it to absolute zero)? Do you mean the energy being emitted by the various radioactive elements? Do you mean the binding energy holding the various chemicals together? Do you mean the binding energy holding atoms together?

I am not interested in the affect energy has on mass
HELLO! ANYONE HOME!

THEY ARE THE SAME THING!

MASS EQUALS ENERGY (with a scaling factor, which you can set to 1 if you use the right units).

Most of the mass in an atom comes from the binding energy holding the quarks and nucleons together in the nucleus. So mass is energy. They are the same thing. Energy = mass. Mass = energy.

Do you begin to see a theme here?

I am only interested in the affect energy has on gravity.

67. I mean mostly thermal energy, so basically it's just a cold rock with the same amount of mass or frationally less mass due to loss of thermal energy.

68. Originally Posted by RichA12
My basic question is if you could take all the energy out of a massive object (yes we know that it's mass would decrease fractionally which would fractionally decrease gravity, but ignore this)
We can't "ignore this" because "this" is what you are asking about.

Why do you think that an objects mass increases when you add energy? Do you think the energy is being turned into atoms or something?

No, it is just the energy's effect on gravity. Greater gravitational effect means the object "weighs" more; i.e. it has more mass.

69. Originally Posted by RichA12
I mean mostly thermal energy, so basically it's just a cold rock with the same amount of mass or fractionally less mass due to loss of thermal energy.
You need:

- the mass of the earth
- its specific heat capacity
- its average temperature

From that you can work out the total thermal energy. From that you can work out how much of the effective mass (gravitational effect) is due to that energy. I am not going top do that research for you.

70. Originally Posted by RichA12
So can you tell me how much gravity there would be if all the energy was taken out of Earth? I am not interested in the affect energy has on mass, I am only interested in the affect energy has on gravity.
All forms of energy are a source of the gravitational field; this can be mass, EM radiation, stress in a solid body, kinetic energy, or any other type of energy. They are all sources of gravitation. The calculation is done via the formula in post 60 - the basic form of the equation reads "space-time curvature <-> energy".

71. Please, someone tell me roughly how much gravity there would be if all the thermal energy was removed from Earth - that equation in 60 is way over my head. Tell me how much 1kg on normal Earth would weigh on an Earth without any thermal energy.

72. Well, I am certainly not going to tackle the Einstein filed equation. And I think it is overkill for this. It just shows that we can use energy and mass interchangeably (they are the same thing, remeber).

Temperature: 6000K (lets assume the entire planet is the same temprature as the core, for simplicity)
Specific heat capacity: 0.5 J g K (that is about right for iron)

Multiply those together, you get 1.8x1031 joules. Quite a lot of energy.

What proportion of the earth mass (i.e. "gravitational effect") is that? Well, divide it by c2 and we get 2x1014kg which is about 0.000000003% of the total mass of the earth. So it will not make a big difference.

So 1kg would weight 0.99999999997kg

Happy now?

73. OK thanks. So you have converted energy to mass and worked out the difference. So it's safe to say that thermal energy has virtually no affect on gravity.

What I don't get is that if all the thermal energy is taken out of Earth, the mass is virtually unchanged and yet e=mc2, therefore energy would be almost exactly the same but it's pretty obvious that our Earth has a lot of energy when compared to a stone cold Earth.

74. Originally Posted by RichA12
OK thanks. So you have converted energy to mass and worked out the difference. So it's safe to say that thermal energy has virtually no affect on gravity.
Yes. Because it is a tiny proportion of the total.

What I don't get is that if all the thermal energy is taken out of Earth, the mass is virtually unchanged and yet e=mc2, therefore energy would be almost exactly the same but it's pretty obvious that our Earth has a lot of energy when compared to a stone cold Earth.
Yes. The thermal energy is a pretty huge amount of energy. But it is tiny compared to the total mass-energy of the planet. 100000000000 times as much energy is present as the mass of the earth. If you want to convert all that mass to energy and remove it ... you will be left with zero gravity!

75. Yep, takes a lot of energy to bind mass, the thermal energy is kind of deceiving. I wonder if the Earth was hot enough to have nuclear activity in it's early days which in turn caused the Earth to have more gravity. Obviously there was a lot of trapped water for a long time before it was released and became the oceans.

76. Originally Posted by RichA12
Yep, takes a lot of energy to bind mass, the thermal energy is kind of deceiving. I wonder if the Earth was hot enough to have nuclear activity in it's early days which in turn caused the Earth to have more gravity.
The Earth still has nuclear reactions going on throughout. Why should this influence the total mass? Energy, and so mass, must be conserved in all interactions.

Originally Posted by RichA12
Obviously there was a lot of trapped water for a long time before it was released and became the oceans.
That's still a matter of debate - whether the oceans primarily came from comets hitting the Earth after its formation, or from chemical reactions releasing water.

77.

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