Theory of Relativity

Quote:

---

Originally Posted by YesNo

I'll have to look at some quantum physics text to see if makes sense that those leptons and quarks are as small as one can get. I wonder if "particle" is even a good metaphor to use to describe them. With the detection of the Higgs boson recently, that theory is probably on firm ground, but I don't know much about it.



I think you are right about the problem. There is a difference between the process of getting closer and closer to an infinite collection of something and actually finishing that process and having the infinite collection to work with.

If one assumes one can actually have infinite sets of things then one can use logic to see what consequences follow even if in the real world infinite sets of things don't exist.

---

Quote:

---

We won't be able to reach that galaxy to test out whether we would need to do anything special or not to play tennis or use a microwave oven. However, from the point of view of anyone on that galaxy moving away from us, we are in that situation right now. They think we're moving away from them at a fast speed.

---

May I ask what galaxy is this?
What I am trying to say is who is THEY in the galaxy?
How does one know there is anyone in that galaxy and if so how can one reach such conclusions if they have never actually experienced it themselves?

Quote:

---

Originally Posted by YesNo

I was trying to think of what space and time might be like without matter or energy. I doubt that space and time could really exist without them, however.

---

Why? Max Tegmark suggested the ultimate multiverse idea that any universe you can think of actually exists. You've just thought of a universe without mass or energy but space and time. So it exists! Even without Max's zany ideas surely in principle it could exist. Why not? Pretty boring place, though :)

Quote:

---

Originally Posted by YesNo

Now that the universe has started, does it go on forever or will matter and energy decay at some point into nothing destroying space and time when it is all gone?

---

The big, basic unbreakable rule of physics is conservation of mass energy - matter and energy CANNOT dissolve into nothing - have you heard of the heat death of the universe? That's been a standard "end of it all" explanation for many decades and it's still basically what the average cosmologist expects. As the universe expands the uniform distribution of energy, "heat", just gets, more and more diffuse tending to nothing - "death".

Any "loose matter" - us, the remnants of our sun after supernova, etc, get sucked into black holes. But as black holes evaporate (according to Hawking) eventually you will have just weakening energy permeating space. I think space and time will still be there, though.

I've never seen it suggested than vanishing small energy levels will result in the destruction of space & time.

Dark energy and dark matter may still be around - we have no idea what they are, so who knows what they will get up to in the distant future. I think the best guess is that they'll just "be there", like now, while "normal" mass energy just gets on with getting more homogenous, and weaker.

Quote:

---

Originally Posted by mal4mac

Why? Max Tegmark suggested the ultimate multiverse idea that any universe you can think of actually exists. You've just thought of a universe without mass or energy but space and time. So it exists! Even without Max's zany ideas surely in principle it could exist. Why not? Pretty boring place, though :)

---

I don't know if thinking something exists makes it exist except as a thought, but that is an interesting idea.

Quote:

---

Originally Posted by mal4mac

The big, basic unbreakable rule of physics is conservation of mass energy - matter and energy CANNOT dissolve into nothing - have you heard of the heat death of the universe? That's been a standard "end of it all" explanation for many decades and it's still basically what the average cosmologist expects. As the universe expands the uniform distribution of energy, "heat", just gets, more and more diffuse tending to nothing - "death".

Any "loose matter" - us, the remnants of our sun after supernova, etc, get sucked into black holes. But as black holes evaporate (according to Hawking) eventually you will have just weakening energy permeating space. I think space and time will still be there, though.

I've never seen it suggested than vanishing small energy levels will result in the destruction of space & time.

---

I think you are right that the likely end of the universe is some sort of heat death. Since the energy is still present, the space-time would be as well, but I think you are claiming that space-time can exist without energy. The reason I think it cannot is because it gets distorted by the presence of energy which makes me think it is dependent on energy.

Quote:

---

Originally Posted by YesNo

I don't know if thinking something exists makes it exist except as a thought, but that is an interesting idea.


I think you are right that the likely end of the universe is some sort of heat death. Since the energy is still present, the space-time would be as well, but I think you are claiming that space-time can exist without energy. The reason I think it cannot is because it gets distorted by the presence of energy which makes me think it is dependent on energy.

---

"The imagination is important. But the imagination without knowledge is like a toilet without water." ~ C A Cafolini

Quote:

---

Originally Posted by YesNo

The reason I think it cannot is because it gets distorted by the presence of energy which makes me think it is dependent on energy.

---

I don't see it - think of the trampoline metaphor for GR - you can think of the trampoline as space and balls lying on the trampoline as planets "distorting" that space. The planets curve space. But take away the planets, and every other "mass-energy ball", and the trampoline (space) is still there.

Why need space be dependent on energy?

Show me the equations my old prof. would say. And those equations would have to predict every known result of physics and some more...

Then again...

By talking about "distorting space" I'm thinking you are are in the realms of GR. But if you are thinking in quantum terms you might have something - but it's already been "discovered" - the concept of "vacuum energy of empty space" (= dark energy?)

Quote:

---

Originally Posted by mal4mac

I don't see it - think of the trampoline metaphor for GR - you can think of the trampoline as space and balls lying on the trampoline as planets "distorting" that space. The planets curve space. But take away the planets, and every other "mass-energy ball", and the trampoline (space) is still there.

Why need space be dependent on energy?

Show me the equations my old prof. would say. And those equations would have to predict every known result of physics and some more...

Then again...

By talking about "distorting space" I'm thinking you are are in the realms of GR. But if you are thinking in quantum terms you might have something - but it's already been "discovered" - the concept of "vacuum energy of empty space" (= dark energy?)

---

It is energy that's dependent on having space. Energy is and will remain an ability of mass to do work. It is the ability of mass to force a displacement. Forget the tranpolin and that stuff. Space doesn't get curved. That would be ridiculous. Space is there for displacement to occur.

The next question that came to mind is this

When does big becomes big? In relation to what?
If we are and we must bear in mind that there is nothing bigger then the universe itself.
In other words when does size becomes a size?

Quote:

---

Originally Posted by mal4mac

I don't see it - think of the trampoline metaphor for GR - you can think of the trampoline as space and balls lying on the trampoline as planets "distorting" that space. The planets curve space. But take away the planets, and every other "mass-energy ball", and the trampoline (space) is still there.

Why need space be dependent on energy?

Show me the equations my old prof. would say. And those equations would have to predict every known result of physics and some more...

Then again...

By talking about "distorting space" I'm thinking you are are in the realms of GR. But if you are thinking in quantum terms you might have something - but it's already been "discovered" - the concept of "vacuum energy of empty space" (= dark energy?)

---

I need to see the equations also to be convinced, but I don't know what they are. The problem with equations is that they may be just approximations to reality especially around singularities.

I went back to the library to look for Orzel's How to Teach Relativity to Your Dog, but it was checked out. So, I'm reading Joseph Mazur's The Motion Paradox instead. It is also a survey written for the curious, but supposedly it will point in some interesting direction since it is more specifically about time and space.

The distorting space concept would come from general relativity. I guess I don't know what space is without the stuff in it to define it.

Cacian asks what "big" is. I assume the space of the universe is finite and expanding, but I wonder if that assumes it is dependent on matter. Cafolini doesn't think space gets curved by matter so then we are back to Newton's force of gravity acting instantaneously over a distance.

Quote:

---

Originally Posted by YesNo

I need to see the equations also to be convinced, but I don't know what they are. The problem with equations is that they may be just approximations to reality especially around singularities.

I went back to the library to look for Orzel's How to Teach Relativity to Your Dog, but it was checked out. So, I'm reading Joseph Mazur's The Motion Paradox instead. It is also a survey written for the curious, but supposedly it will point in some interesting direction since it is more specifically about time and space.

The distorting space concept would come from general relativity. I guess I don't know what space is without the stuff in it to define it.

Cacian asks what "big" is. I assume the space of the universe is finite and expanding, but I wonder if that assumes it is dependent on matter. Cafolini doesn't think space gets curved by matter so then we are back to Newton's force of gravity acting instantaneously over a distance.

---

No. Actually we are not back to forces acting at a distantce. That would be ridiculous. There has to be physical contact. Forces at-a-distance do not provide it. Newton did not claim the action of forces at-at-a-distance. His model was one of behaviour, based on Kepler's descriptions. And so were Halley's predictions.
Stringettas with papal cheese were an invention to fake the appearance of physical contact. A funny cardinalia myth established to keep going with the BS.
The M&M experiment was another funny idiocy if taken as scientific. Aristrotle spoke of the Aither (the ether they went to test). That's similar to the palpitations of some freak that suspects there is someone at the door, goes to check and not finding anyone says "he wasn't there. So, there has to be a principle based on why he wasn't there." Ridiculous.
What's going on is based on travelling through densities. That's dynamic, and that's where the answers are and have been found. The speed of light or ANY other matter could be ANY based on the density of the area they are travelling. And this is no longer a static situation measured by matter/volume, but a very dynamic one where V (the full vector) play a part. Density encountered changes with V. Jesus knew this and that's why he walked on water. The pigmies of Africa learn how to run over swamps. Mythbusters walked over a swiming pool where the density of its water was increased with corn starch. Have fun. :nopity:

Quote:

---

Originally Posted by cafolini

No. Actually we are not back to forces acting at a distantce. That would be ridiculous. There has to be physical contact. Forces at-a-distance do not provide it. Newton did not claim the action of forces at-at-a-distance. His model was one of behaviour, based on Kepler's descriptions. And so were Halley's predictions.
Stringettas with papal cheese were an invention to fake the appearance of physical contact. A funny cardinalia myth established to keep going with the BS.
The M&M experiment was another funny idiocy if taken as scientific. Aristrotle spoke of the Aither (the ether they went to test). That's similar to the palpitations of some freak that suspects there is someone at the door, goes to check and not finding anyone says "he wasn't there. So, there has to be a principle based on why he wasn't there." Ridiculous.
What's going on is based on travelling through densities. That's dynamic, and that's where the answers are and have been found. The speed of light or ANY other matter could be ANY based on the density of the area they are travelling. And this is no longer a static situation measured by matter/volume, but a very dynamic one where V (the full vector) play a part. Density encountered changes with V. Jesus knew this and that's why he walked on water. The pigmies of Africa learn how to run over swamps. Mythbusters walked over a swiming pool where the density of its water was increased with corn starch. Have fun. :nopity:

---

Jesus did not walk on water cafolini.
If you believe that you believe anything.
Jesus was a person just like you and mme and so he did not cure diseases either. He did not have magic hands.
And he most definetely did not turn water into wine. I thought he walked on it.

Quote:

---

Originally Posted by YesNo

I need to see the equations also to be convinced, but I don't know what they are. The problem with equations is that they may be just approximations to reality especially around singularities.

I went back to the library to look for Orzel's How to Teach Relativity to Your Dog, but it was checked out. So, I'm reading Joseph Mazur's The Motion Paradox instead. It is also a survey written for the curious, but supposedly it will point in some interesting direction since it is more specifically about time and space.

The distorting space concept would come from general relativity. I guess I don't know what space is without the stuff in it to define it.

Cacian asks what "big" is. I assume the space of the universe is finite and expanding, but I wonder if that assumes it is dependent on matter. Cafolini doesn't think space gets curved by matter so then we are back to Newton's force of gravity acting instantaneously over a distance.

---

Do you know YesNo I personally do not believe gravity exists. I have my own reasons to think that.
I think the apple fell because it was ready/ripe to fall. When a fruit is a ripe it falls off the tree.

Another point when does distance becomes distance? It is perspective rather then further or closer away.
I am not sure.
It is the same as the size issue.

I agree with you that the apple falls when it is ripe.

Daniel Chamovitz's What a Plant Knows: A Field Guide to the Sense is a survey of what is known about plant sensation. If I recall correctly, plants will ripen their fruit when they detect a certain "smell". Since they do not have noses, their sense of smell functions differently than ours. What Chamovitz does is finds correlations between our sensations and plant sensations and then shows if there is scientific evidence that plants actually do have such sensations. The only comparable sensation that he could not find was hearing.

I finished Mazur's The Motion Paradox. It was a history of the ideas of motion and illusion from Zeno to the present day. Zeno claims that a continuous space and time, which is what our senses perceive and our mathematics models with the continuous number line, implies change is an illusion. The continuous model of space and time has had to be patched with the discovery that space and time are relative and the speed of light is constant, the discovery that dense mass increases the curvature of space and the discovery that the smallest particles behave also as waves fluctuating through quanta and not continuously. The search for a unified theory of quantum mechanics and gravitation is an attempt to replace the patched mathematical model of space-time with a new model.

YesNo thank you for the post.
Here is my next thought

does weightlessness exists ?
Because if it does not then stilness cannot be either.

I don't really have any answers, just some ideas of what makes sense to me at the moment based on reading and trusting, perhaps too eagerly, what I've read.

Weightlessness is what one would experience in "free fall" which is the inertial frame of reference that general relativity claims the laws of physics should be verifiable in. Special relativity only holds for frames of reference where the relative motion of the frame is uniform, what the Mars rover was in while en route to Mars. Although it is called a kind of "fall", it is what one would experience orbiting the earth, weightless and motionless.

I don't know what you mean by "stillness cannot be either". It sounds like what one would experience when one does not have fear or desires. I think one could experience that while on earth with the earth keeping us grounded.

Quote:

---

Originally Posted by YesNo

The distorting space concept would come from general relativity. I guess I don't know what space is without the stuff in it to define it.

---

Why does it need "stuff in it" to define it? The inside of a watering can is not defined by water ... or the can ... or air. It's just space.

Quote:

---

Originally Posted by YesNo

Cacian asks what "big" is. I assume the space of the universe is finite and expanding, but I wonder if that assumes it is dependent on matter.

---

One should never make assumptions with this crazy stuff :) Read what the crazy cosmologists write. The current favoured model is an infinite, expanding space. The infinite space was created at the moment of the Big Bang... note it's now thought to be "flat", a nice 3D space, so nice and easy to visualise (?)

As infinite space was "just there" after the Big bang, I can't see matter had much to do with it. In any case, one could imagine a universe that is just flat and infinite without matter. Couldn't one?

Anyway, matter is just an impermanent fluctuation in the quantum vortex... when it's all been swallowed into exploding mini Black holes and there will just be energy.. and that will (due to expansion) attenuate into a level indistinguishable from vacuum quantum fluctuations... so space will indeed by all there is (unless you want to count quantum vacuum fluctuations...)