There is no "fabric of space"

[Guido]

I'm gonna play devil's advocate here and go on a limb by saying gravity does not affect the fabric of space because there is no such thing. Gravity affects other objects the same way a magnet affects ferrous objects. Nothing to do with space fabric at all.

 

Why we can't compare gravity with a magnet? They both generate a "field of strength" that requires no medium, yet why does space need to have a "fabric"? Rolling a steel bearing towards a magnet will cause it's path to deflect the same way a planet does when it nears a star.

 

Why does gravity need to warp space, yet a magnet doesn't?

[Vagabond -SC2-]

If a magnet was large enough or better yet strong enough then would it possibly warp space?

[Guido]

I don't think so because it would only affect ferrous items. BUT, if this planet only contained ferrous items, then we humans would probably believe that it would warp space because everything (in our world) would be affected.

How are we sure that everything in our universe is affected by gravity?

And, if a magnet can affect certain things without warping space, why can't gravity do the same?

[pgrmdave]

Gravity warps light's path. Since light travels in straight lines, that must mean that the 'path' is curved. Thus gravity must affect that 'fabric'.

[C1ay]

Gravity warps light's path. Since light travels in straight lines, that must mean that the 'path' is curved. Thus gravity must affect that 'fabric'.

Maybe gravity is just affecting the photons, not some supposed medium they are traveling through....

[ldsoftwaresteve]

Gravity warps light's path. Since light travels in straight lines, that must mean that the 'path' is curved. Thus gravity must affect that 'fabric'.

But if McCutcheon is correct, the photons of light are expanding along with all other configurations causing the effect described as a warping of space-time. Same phenomenon just a different way of looking at it. Relative, in other words. Einstein deals with the effect while McCutcheon deals with the cause.

[cwes99_03]

I don't think so because it would only affect ferrous items. BUT, if this planet only contained ferrous items, then we humans would probably believe that it would warp space because everything (in our world) would be affected.

How are we sure that everything in our universe is affected by gravity?

And, if a magnet can affect certain things without warping space, why can't gravity do the same?

Actually, that is not true.

 

Strawberries can be levitated in a magnetic field of great strength. It has been done (in Korea or Japan I believe).

[Guido]

Actually, that is not true.

 

Strawberries can be levitated in a magnetic field of great strength. It has been done (in Korea or Japan I believe).

Why does it take so much more energy to levitate a strawberry compared to a steel ball of same mass? If the magnetic energy were affecting the fabric of space, then all objects (of equal mass) on that fabric would be affected equally, regardless of what they're made of. But the fact that objects of same mass are not affected equally by a magnetic field means (to me) that there is no fabric being warped, that the field is acting directly on the object.

 

If magnetism doesn't require a fabric to affect objects, who does gravity?

[Vagabond -SC2-]

Could this so called "fabric" just be a means to an end, say so one can understand or perhaps diagram what is going on?

 

I like the light photon point earlier. Yes, the light is bent. Light is both wave and particle, perhaps the gravity is effecting the particle part.

 

On the other hand dismissing the levitating strawberry did not really make sense to me. There are lots of things that require vastly varying quantities of energy to make work/move/produce etc not all make complete sense.

I good question would be how is the strawberry levitated?

Fruits are not ferrous substances? Is there trace amounts of ferrous ions within the strawberry to allow this to happen? If not then what is forcing it to levitate?

Is there any situation in which a strawberry would be levitated with less energy then a metal ball?

If you did this on the moon the strawberry would require a lot less energy.

[Pyrotex]

Strawberries can be levitated in a magnetic field of great strength. It has been done (in Korea or Japan I believe).

Yes. In Japan, much of the annual crop of strawberries is transported to Tokyo by MagLev (magnetic levitation) train. :hihi:

[Pyrotex]

Maybe gravity is just affecting the photons, not some supposed medium they are traveling through....

pgrmdave is pretty close to having an answer for Guido.

 

Gravity has been compared to magnetism for centuries. They just aren't alike enough to support any argument that draws parallels between them.

 

You can generate a magnetic field with electricity in some moving wire. Easy. You cannot generate gravity. Magnetism affects only certain atoms, gravity affects all. Magnetism produces secondary effects, like generating electricity. Gravity has no secondary effects. Magnetism is bipolar in shape, a field has a distinct N end and a S end ("two poles"). Gravity does not; gravity is monopolar. The equations that describe bipolar and monopolar fields are not the same and cannot be "merged".

 

Magnetism appears to "work" because of certain properties of and within the atom. Gravity appears to "work" independently of any property of atoms. Magnetism doesn not affect photons or bend their paths. Gravity does. However, the theory of light indicates that photons have a "spin" property that would make them immune to any ordinary field-forces. Therefore gravity cannot be a field-force. It must be something else.

 

If photons cannot be affected by fields (or the math would go to hell) (and lab experiments verify this) then they must travel in straight lines. But a straight line in what kind of geometry. There is a thing called a geodesic that is a straight line in flat Euclidean geometry, that is also the "shortest path between any two points" in all other rational geometries. Photons follow geodesics. If a photon follows a geodesic and curves around the Sun, then it follows that the Sun is affecting ("warping") the geometry of its local space.

[Guido]

Could this so called "fabric" just be a means to an end, say so one can understand or perhaps diagram what is going on?

It would be OK if it were described as a "teaching aid", but general relativity predicts that gravity warps space, which affects the movement of objects (including light) travelling in this warped portion of space. It doesn't say gravity affects the objects directly.

 

I like the light photon point earlier. Yes, the light is bent. Light is both wave and particle, perhaps the gravity is effecting the particle part.

I like C1ay's response.

 

On the other hand dismissing the levitating strawberry did not really make sense to me. There are lots of things that require vastly varying quantities of energy to make work/move/produce etc not all make complete sense.

I good question would be how is the strawberry levitated?

Fruits are not ferrous substances? Is there trace amounts of ferrous ions within the strawberry to allow this to happen? If not then what is forcing it to levitate?

Is there any situation in which a strawberry would be levitated with less energy then a metal ball?

If you did this on the moon the strawberry would require a lot less energy.

I did not intend to dismiss the levitating fruit - I believe it did happen. Probably it contains enough iron to levitate.

 

I was simply trying to point out that I don't believe a magnetic field warps space, because if it did then the same way a 10 gram steel ball is attracted to the magnet (by following the curvature), so will a 10 gram rubber ball because they're both following the same curvature. So the fact that a magnet acts directly on the object (instead of the object reacting to the curvature) leads me to question why can't gravity act directly on the object too?

 

Is there any situation in which a strawberry would be levitated with less energy then a metal ball?

In a magnetic field? I don't think so. But using air pressure from below would levitate the strawberry easier than a similar mass metal ball.

 

If you did this on the moon the strawberry would require a lot less energy.

And the metal ball would require a lot less energy also.

 

Remember, I'm playing devil's advocate as a way to pick people's brains (and my own). The only point I can think of that helps prove the existence of a fabric is the increasing redshift of light the "older" it gets. I don't see what would cause light to stretch without an outside force being acted on it (stretching fabric). But then again, some scientists think light gets "weak" over time.

[pgrmdave]

Why does it take so much more energy to levitate a strawberry compared to a steel ball of same mass?

 

I did some research and I came across this site:http://www.badscience.net/?cat=34

 

Here's what it has to say (in the June 3rd, 2004 entry)

 

Diamagnetism was first thought through 150 years ago: the electrons orbiting an atom, being charged, are going to readjust their orbits when you stick them in a strong magnetic field, as you might expect. But in doing so, they then create their own magnetic field. To be fair [coughs] the effect is so weak that the rest of the world is roughly one billion times less magnetic than a lump of iron but yes, hands up, that doesn’t mean it’s not significant.

 

But most promising is the work of Berry and Geim, who in 1997 levitated practically everything they could get their hands on, from hazelnuts and pieces of pizza to frogs and a mouse. Watching the video of a frog hovering in mid-air is a humbling and weirdly tranquil experience. For the anti-vivisectionists among you there is a film of a levitating strawberry.

 

 

Wikipedia also has a good article on diamagnitism: http://en.wikipedia.org/wiki/Diamagnetism

[Guido]

How come a 10 ton space station requires the same gravitational energy to maintain in orbit as a 10 ton meteor in the same orbit, YET a 100 gram frog requires exceptionally more energy to magnetically levitate than a 100 gram chunk of iron?

 

The current answer in the scientific field is because a magnetic field acts directly on the object and the substance it's made of (which is why different substances require different energy to be affected), while gravity acts only on the fabric of space and any objects of equal mass caught in that part of fabric are affected equally, regardless of substance.

 

My real question that prompted this thread is why can magnetism act on an object directly, yet gravity can't? It has to go through a medium (the fabric).

I don't see why gravity requires a medium (except for the redshift point I made above).

 

I guess we'll have to wait an see what LIGO et. al. says about that.

[Pyrotex]

How come a 10 ton space station requires the same gravitational energy to maintain in orbit as a 10 ton meteor in the same orbit, YET a 100 gram frog requires exceptionally more energy to magnetically levitate than a 100 gram chunk of iron?....

I keep seeing this idea of gravitational energy in several threads. It appears that a misconception of "energy" is quite commonly believed.

 

It does not "take" any gravitational energy to maintain the space station's orbit. Or the Moon's or anything else. It takes NO ENERGY of any kind. Once a satellite has the proper velocity, it takes NOTHING AT ALL for it to maintain its orbit. Even that is misspoken--a satellite does not "maintain" its orbit. Nothing does. The satellite is in free fall. Period. It is freely falling. It is under the influence of a FORCE (not energy)--the force of gravity. This force gently curves the freely falling path of the satellite into an ellipse. NO energy is used, transferred, or expended by either the satellite or the Earth or the gravitational field.

 

So, the way you worded your question makes the entire question unanswerable. I'm really sorry about that. I don't mean to criticize or belittle anybody's understanding, but sometimes the words chosen make all the difference in the world. Thank you for your patience.

[Guido]

I appreciate you pointing that out. The more errors people find in my posts, the more I learn. And that's why I'm here.

 

My understanding is:

The force of gravity act equally on objects having the same mass yet the force of magnetism is more related to an object's substance than it's mass?

 

Does the above statement (if true) have anything to do with the fabric of space, and if so, how?

[Pyrotex]

...The force of gravity act equally on objects having the same mass yet the force of magnetism is more related to an object's substance than it's mass? Does the above statement (if true) have anything to do with the fabric of space, and if so, how?

You are gracious, thanks. :)

The force of gravity acts equally on all objects at the same distance. A bulldozer and a thumbtack in the same orbit will travel the same ellipse, despite their difference in mass.

Magnetism is indeed related to an object's substance, particularly the structure of the electron orbitals around the atoms.

 

The "fabric of space" is a turn of phrase used to represent an idea, in an attempt to make the idea somewhat more graspable. There is no fabric. But empty space does have properties! It has specific electrical and magnetic properties just like a piece of copper wire! (But not the same values, of course) It has length, dimension, volume.

 

The association of these facts is something like this: magnetism acts through a "force field" which can be detected and generated. Gravity, acting on all substances alike, even on photons (!!!) cannot be a "force field". So what is gravity?

 

If you created a perfect sphere one molecule thick and had a way of precisely measure each and every cubic centimeter and adding them all up, you would get the volume. Put the Sun at the center of your sphere and repeat. You get a larger volume.

 

One way of "expressing" this is to say that gravity is not a force field but a stretching of the geometry of space. Does it really? :) :phones: It's just a way of describing the difference in volume. A photon appears to "bend" around the Sun (slightly). Does it really? :wave: :hihi: It's just a way of describing or interpreting experimental results. Atomic clocks in different orbits around the Earth run at different speeds. Do they really? :lol: :shrug: You can't be in two different (moving) places at the same time so you have to do complicated comparisons and it appears that they do. If we replace 3D Euclid geometry with 3D Riemann geometry, which says that some straight lines are "warped" in certain ways (but still remain "straight" lines, you know) then all the experiments agree with the math!

 

The Sun does in fact affect photons and thumbtacks. How to get all the experimental observations to agree? And to agree with Newton and Michael-Morley and others? And to agree with electro-magnetic radiation (light) theory? Conundrum!!! :friday: :)

 

The only way so far is to say that gravity affects space itself, and this warping of space is what causes objects and photons to travel geodesics that do not appear straight to us mortals with our bamboo yardsticks.