losfomot

It seems that I am wrong about this... most of the galaxies that we see are receding from us faster than light already. See... that's just weird.

Yes we do see endless (well... not endless) amounts of galaxies when we extend our view deep into space. A patch of space which, through an average telescope, shows mostly blackness is actually rich in galaxies. The deepest we've ever looked, I believe, is called the Hubble Ultra Deep Field. You can check it out here.

In our universe, we look in one direction, and we can see galaxies roughly 13-14 billion light years distant. We can't see further than that because things are moving away from us at close to the speed of light, and are redshifted out of existence (so to speak). We see the same thing in the opposite direction. If we were to pick a galaxy from each direction, each at a distance of 13 billion LY (we'll call them galaxy A and B), we would be looking at 2 galaxies that are moving away from eachother faster than light. Nothing can move faster than light, so how is this possible? This has been explained by the fact that the motion of these galaxies, relative to eachother, is due to space 'expanding', and therefore is not subject to the speed limit of C. However.. 'fact' seems like a strong word here. If space is not a physical entity to expand, then it seems like this explanation breaks down. If 'space' is not really expanding, then galaxies are simply moving away from eachother faster than light (thereby (assumedly) increasing the area of the universe (maybe volume would be a better word?)). So we are still left with the question... How can these objects be moving apart faster than the speed of light?

I thought that this was a good idea at first, I like the idea that threads be kept 'on track'... but too much was junked... better to have a thread that gets off track than to have a thread that is amputated. Oh well, now I know. Funny how this one got off track right away again.

OK, How about this... If you were to set up a mirror on a stat. sat. and then shot a laser at it (from Earth) to reflect back down at you, would the laser be shot back at a single spot, or would it move around?

1- Is an object in geostationary orbit, pointing in a steady direction toward the Earth (not rotating) considered to be at rest WRT the Earth? 2- If X and Y are at rest WRT eachother, and Z and Y are at rest WRT eachother, then Z and X must be at rest WRT eachother. True or False? Thanks.

I've read the book, and the movie is going to rock. Getting down to business!

So, LIGO has been operational for a few years now, and they haven't picked up a single gravitational wave? So it just sits there, running, until some huge event occurs close enough that LIGO might detect it? Can't they make the arms longer, and thereby, more sensitive, so that it might pick up something from a nearby binary? And shouldn't the facility have 3 arms to cover the 3 dimensions of space? And (one more, sorry) shouldn't we be able to pick up gravitational waves from the moon? It's an accelerating mass, isn't it? Probably should've started a new thread for this

But now we've eliminated curved space again. If gravity is just a particle that is exchanged between masses, then there is no need to talk about mass warping space and relativity is nullified. See this was my problem right from the start. How can relativity be right about mass changing the geometry of space and still there is such a thing as a graviton. The only way they can both be right is if gravitons are constantly altering the geometry of space, but your description of gravitons doesn't show that at all. You're saying that gravitons only interact with other massive bodies. See, if each graviton has energy and that energy had to come from somewhere then: A- The Earth is constantly losing mass/energy B- The Earth only emits gravitons toward another massive body which, in turn, emits gravitons back to the Earth. or C- The Earth does not emit gravitons, but rather has a constant field of gravitons around it that interacts with any mass entering the field. (I'm not sure if this option even allows for gravitons as particles) The only one of these choices that could include relativity is A. B and C are self sustaining, the concept of warped space doesn't exist with them. Sorry, I'm not trying to be a pain, I'm just trying to understand.

And now, just like that, I can understand how gravitons and relativity might exist together. So, it may not be the mass itself that tells space how to curve, but rather a by-product of mass, a particle that mass produces, called the graviton. It's amazing how something worded just right can bring forth enlightenment, thank you. Of course, gravitons must come with some heavy baggage, so to speak. For one thing they must be continually emitted in ridiculous, near infinite number. And they must have energy to curve spacetime... if mass emits them in amounts that can alter the geometry of space, that energy must be substantial. Where does it come from? Is the Earth constantly losing mass at a rate equal to the energy needed to curve spacetime the way it does? And if the graviton is a particle, does the gravity, it itself produces, affect it? (I'm sure that I've seen this question in another thread, so I'm not asking for an answer, Im just giving examples of the numerous problems that must be associated with a force carrying particle for gravity). I kinda like my idea of mass displacing space better.

I think the main question is 'What is space?' (or spacetime) For relativity to talk about space being stretched, warped, curved, whatever... it must by a physically connected whole, just like the sheet of rubber. A ball on a sheet of rubber stretches the rubber, not just at the point of contact, but beyond. There is no force particle necessary to jump back and forth between the ball and the rubber to tell the rubber how to form itself at every single point of it's warp because the rubber can tell itself. It's all connected. So is space. It is a physical thing that we can feel (gravity) but not actually touch or see (yet). In a way, we can even see it (gravitational lensing). It must be a physical thing which is physically connected, or all talk of warped, curved, and expanding space is absolute nonsense (or, at least, a misnomer). And a physically connected space with a geometry that can be warped, does not need a force particle to tell it how to warp. If you push on a section of space, all connecting sections of space will be pushed as well, only to a lesser and lesser degree as distance increases from the original push. Now you are left with HOW a section of space might be pushed, or stretched, or warped, or curved. Mass. How/Why does mass warp space? Perhaps it displaces space. However, that seems unlikely since an atom is mostly comprised of space itself, so it would take an awful lot of mass to displace any significant amount of space that we might notice any 'gravitational effects'.... wait a minute... it does take an awful lot of mass... that could explain why gravity is so weak. Average mass is so anti-dense (I can't think of the opposite of dense at the moment) that it takes an enormous amount of it to significantly displace (or warp) space. Well, it's a possibility. Anyway, the alternative view is that space is nothing. It's just a void that happens to have some stuff in it and happens to be getting bigger and bigger. In this case you do require a force particle to explain gravity, but to say that gravity is the result of warped space in this view would be wrong. You can't warp nothing. You can't stretch it either. I don't think nothing can curve. So here we have a universe in which force particles (we'll call them gravitons) are responsible for the 'force' called gravity. Warped space has nothing to do with it. And that is what I see... one or the other... both doesn't make sense. Do you see what I mean?

Which is exactly what I'm saying. I have to disagree with you there. I think you are saying they exist. Your entire argument for gravitons is just the opposite question: How could space be warped without gravitons? see: You can't put forward an argument that says gravitons MUST exist (which is what you're saying) and then say

Oh, I figured it had to do with magic, mentalism and all that, If I had known it wouldn't show up in the active topics list, I wouldn't have posted it here.

Just a quick question.... why can't I see this thread on the main page? Usually if I post something and then click on the home link for sfn, I can then see the thread at the top of the list... is pseudoscience excluded from that honor or are my settings wonky, or what?

I am curious about spoon bending. How is it done? It looks pretty impressive on TV. You can buy kits that will teach you how to do it for like $20. Do you need a special spoon or is it all just sleight of hand stuff? Can anyone here do it?

Not entirely, no. The gravitational term in the timing correction could be because: A- A GPS satellite is in freefall, and therefore does not experience time dilation (from the Earth's mass) while we on Earth's surface do... hence a timing correction. Or B- A GPS satellite is further away from the surface than we are, and therefore experiences less time dilation (from the Earth's mass) than we do... hence a timing correction.

When you are in freefall or in orbit around a planet, you no longer feel gravity... you become weightless. Do you still experience time dilation at the same rate as you would if you could feel gravity. For clarity.... John is standing on a platform on the moon. Jane is orbiting the moon at the same height as the platform that John is standing on. Does time pass at the same rate for both Jane and John? Damn... I can see I'm going to get into some trouble with the fact that Jane and John are moving WRT one another... hopefully you know what it is I am asking.

I don't know a lot about gases, but it sounds like you could run a motor with this gas and never have to refuel it.... sounds too good to be true, so probably not.

I don't understand how this could be right. It looks like a perfect setup for FTL communication: Fire two entangled photons in opposite directions, one at a manned station 1 AU away, and the other at a manned station 1 AU away. Have double slits for them to pass through at each station. But at one of the stations, garner which path information from the entangled photon if you want to say hello to the other station 2 AU away. This will destroy the interference pattern for the other photon instantaneously. The other station could easily read it as: Interference pattern = no hello No Interference pattern = hello

But gravity is not a 'wave' theory' date=' that's my point. I'm not saying that gravity waves cannot exist, Im sure that a dense vibrating mass, or a tight binary system, or some massive event like a supernova could all make 'gravitational waves' But that does not make relativity a wave theory of gravity. Water can come in some pretty huge waves too. Heck, you can make waves in a tub full of marbles... marble waves.... ha I bet you the wave function of a marble is pretty damn small. If the ball/sheet analogy is just a way of picturing it and the real reason the moon is orbiting us is gravitons, then there is no warping of space at all. To me, this is what your saying. Warped space does not exist, gravitons are what tethers the moon to us. Do you see what I mean? It can be one or the other, but not both. We are not dealing with a wave/particle argument, we are dealing with a warping of space/particle argument. I understand that the smaller things are, the stronger the wave function. And I find the fact that light, or even electrons and other small particles, exhibit characteristics of both a wave and a particle... I find that fact amazing. I find the double slit experiments fascinating, and if someone tried to tell me that is how things worked without showing me experimental evidence, I would not believe it. So maybe you are right... maybe. It just seems not a satisfactory explanation to just point at wave/partical duality and say 'Oh, I guess you don't believe in that either?' (that's not meant to be a direct quote) Yes I believe in that, but only because there is experimental evidence to back it up. Back to the ball and sheet analogy, you said there is physical contact, and that is what causes the sheet to contort, but move two inches away from the bowling ball and the sheet is still contorted. There is no physical contact at this point, and yet a marble will still change direction if rolled over this area. THAT is how the moon is orbiting us (I thought.) The Earth has physical contact with Space (if such a thing is fathomable) Space is stretched, to a lesser and lesser degree the farther you get from the massive object, just like the ball and sheet. Relativity talks about more than just the effects of gravity, it talks about the mechanism (warped space). Gravity does not need to travel. In the rest frame of the sun, for example: The mass of the sun has warped the space around it and the planets move accordingly, the warp is permanent as long as the mass of the sun remains the same. Anyways, you are probably right, and I am probably wrong, I just wish I could understand how both ideas could be right, when they seem like two completely seperate mechanisms of gravity.

I am going to second this call for an explanation. Transdecimal's original question, coupled with Rekkr's question above seem unanswered. I am led to believe that gravity (according to relativity) is the warping of space, by mass, just as a bowling ball placed on a rubber sheet warps the sheet so that a marble rolling by will get caught in the dip and orbit the bowling ball. If this is truly what is causing the 'force' we call gravity, then there is no need for a force particle, in fact they should not exist at all. To go a step further, it would seem to me, the confirmed discovery of the graviton should completely disprove relativity. It does not make sense that relativity could be right AND there are such things as gravitons. Unless, like Rekkr suggests, space is made of an aether of gravitons. So, to quote Rekkr "Someone please explain."