lol

if we get more space are we loosing time?

its all to do with between a and b but thats funny

http://en.wikipedia.org/wiki/Zeno's_paradoxes

and how do point particals...with no internal parts (as they are fundemantal)... interact?.... on the quantum level a place seems to be a fuzzy idea..?

if we live in a world of gravitons and ''fields'' is there any such thing as space time or just relations between things....

and how does a stupid monkey that believes in now and then and here and there make any sense of a universe where light lives in the real world ??


*?*

no here no there no way to tell one place /time from another.....OH!! like a perfect void of nothingness.....perfect symetry

shoot me

lol

If Pamela and Fraser are each still holding on to their end, and we're standing (floating?) next to Damien and his scissors, and we observe Pamela and Fraser receding at 36.75km/sec... then both (cut) ends of the rope will eventually accelerate to 36.75km/sec away from us, depending on the elasticity of the rope... unless the inertia of the rope is somehow greater than the Hubble Constant, in which case we wouldn't observe Pamela and Fraser receding???

...someone pass another beer?

__________________
If something is in me which can be called religious then it is the unbounded admiration for the structure of the world so far as our science can reveal it... of the manifestations of the profoundest reason and the most radiant beauty, which are only accessible to our reason in their most elementary forms...
Albert Einstein

now the bloody rope is elastic ?? lol o ****

and it has inertia????? you said inertia *faints*

Even my cat doesn't get Quantum Mechanics.

And he knew Schrodinger.

Apparently.

__________________
If something is in me which can be called religious then it is the unbounded admiration for the structure of the world so far as our science can reveal it... of the manifestations of the profoundest reason and the most radiant beauty, which are only accessible to our reason in their most elementary forms...
Albert Einstein

Let's say that the rope doesn't stretch.

Before the rope is cut, how does expanding space appear to Pamela and Frasier? Suppose each is in a location with bits and pieces of debris. Suppose the debris is stationary relative to that grid of space. Is this debris flying by Pamela and Frasier at 36.75 km/sec?

How much tension is in the middle of the rope before it is cut?

How much time is required for Pamela and Frasier to reach 36.75 km/sec away from damian1727,with his scissors, after the rope is cut?

If the rope doesn't stretch, how long does it take the information that the rope has been cut to reach Pamela and Frasier, putting an end to their game of (gentle?) tug of war?

What happens if NHR+ gets a longer rope...lots longer. Now the rope is so long that Pamela and Frasier see debris moving past them in their respective grids of space at the speed of light! Can each feed out more rope and see things go by even faster? Will time go in reverse if it does?

I'm pretty sure we can't say the rope will not stretch - even it was a steel rod - it's made of atoms like any other matter. Even a neutron star stretches. I think. (Never tried! )

Information can travel up and down the rope no faster than c (the speed of EM which binds the atoms together - in fact less I think, as light slows down in matter e.g. refraction in a prism).

If the rope were longer, so long it would in theory extend to regions of space which were receding at greater than c, there would be no way to get Pamela and Fraser there, they can't travel faster than c either, so would never catch up.

I suspect relativity would prevent our experiment even with the 1 Mpc rope (my brain hurts if I try to figure it out). Maybe the only experiments you could do in nature would involve light - which is what astronomers do every day when they observe distant galaxies anyway. Maybe there is an experiment you could devise involving cosmic rays, which from memory are massive particles traversing space at near c. The only other place you could observe particles at relativistic speeds is an accelerator - which would be way too small to observe the Hubble Constant, and which is gravitationally and atomically bound anyway. Or maybe something with gravitational waves - perhaps when LIGO goes into orbit?

So, my guess for the debris problem is - Pamela and Fraser will never observe the debris 'cos they can't (really) get there. If we stay with a thought experiment - I'm tempted to say the debris would be flying past, and there is no 'extra' tension due to the expanding universe. But I'm sure there is some reason everyday intuition is wrong, some reason that invalidates the experiment on some level.

__________________
If something is in me which can be called religious then it is the unbounded admiration for the structure of the world so far as our science can reveal it... of the manifestations of the profoundest reason and the most radiant beauty, which are only accessible to our reason in their most elementary forms...
Albert Einstein

It would take 1.6 million years for Damian to observe the effect--0.5 megaparsec=1.6 million light years. This is why I think nature invalidates the experiment in some relativistc way - no one can chug beer for 1.6 million years...

__________________
If something is in me which can be called religious then it is the unbounded admiration for the structure of the world so far as our science can reveal it... of the manifestations of the profoundest reason and the most radiant beauty, which are only accessible to our reason in their most elementary forms...
Albert Einstein

What if Frasier decided to toss the long rope and come up with something lighter. He makes a Megaparsec piece of Nanotube and coils it up. The tube is driven over to Pamela's house where they sigh and pick an end to take for their next game of tug of war. The first thing they notice is that the tube is getting 73.5 km shorter each secord! How do you grab that and pull?

Clearly I don't have any idea what I am talking about. What would really happen?

The gap in my understanding (in a field of many) touches on an issue that I think Steve brought up in another inflation discussion. Are the units of dimension (say planck length) inflating between two points or are there more unit being squeezed in over time.

Please correct me where I fall off track here. We have inflating space as a model for the expansion of the universe. Would shrinking matter (and decelerating light) work as an alternate model? Could the size of the Universe be constant while the matter within it shrinks, and appears to grow further apart?

The best I could find out was 'we don't know how space expands' but I got the impression the planck length probably isn't changing. I wonder if we could even tell - wouldn't one have to be 'outside' the universe to observe it? The best guess seems to be that vacuum energy and/or virtual particles somehow expand space--then there is even more space, more energy/particles, and space expands even more. The effect must be weaker than the electro-magnetic and strong nuclear forces, and stronger than gravity only on the largest scales. Something similar (or not?) is said to be responsible for inflation - but tied up with thermal (like?) phase transitions, like water changing to ice, when gravity condensed out of the super-force? If the universe ends in a Big Rip - then expansion/dark energy eventually wins somehow...

Of course I could have no idea what I'm talkin' about too! I usually get only so far and my brain melts - or it's time to mow the lawns.

I like your rope conundrum. I'm still thinking about it - maybe others will chip in?

Maybe I need to go listen to Fraser and Pamela's show again - unfortunately there weren't any show notes with the Inflation episode - I've found they usually help!

__________________
If something is in me which can be called religious then it is the unbounded admiration for the structure of the world so far as our science can reveal it... of the manifestations of the profoundest reason and the most radiant beauty, which are only accessible to our reason in their most elementary forms...
Albert Einstein

I've been trying to think about this CPMosh's "rope conundrum", and I have to say I just don't know WHAT would happen. All real ropes (or nanotubes, for that matter) would HAVE to be somewhat elastic, and also I don't think there really is (or ever will be) any ropes some megaparsecs in length... think about the sheer mass of such a rope! But thinking it just as a thought experiment... my brain still seems to shut down.

Interesting thought, though.

I don't think shrinking matter and decelerating light would do very well as an alternate explanation, but anything "scientific" to base this "gut-feeling" on, that's totally beyond me, of course...

Where do we stand so far?

Would our coiled-up Megaparsec-long nanotube contract at 73.5 km/sec? Imagine the coil flipping around, in the back of Frasier's car on the way to Pamela's house, as the nanotube gets shorter.

Or... What if the coiled nanotube didn't contract? Pamela and Frasier straighten the tube and do find, however, the expanding space drifts by each (now distant) end at 36.75 km/sec (relative to the center of the nanotube).

Are there a boatload of observations that the shrinking matter (and decelerating light) model fails to explain? Would the alternate model rescue us from the need for a Dark Energy concept?

Forgive me for flogging this horse. I am grateful to everyone for taking the time to help explain this.

There's a transcript for the inflation episode now:
http://www.astronomycast.com/cosmolo...-58-inflation/

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Fraser Cain
Publisher
Universe Today - Free space news delivered by email every weekday.

Ok. I'll have another crack at this... fortune favours the bold!

As long as the nanotube is in Fraser's truck - or anywhere in the Milky Way (or any other galaxy) - it ain't gonna shrink. Space does not expand within gravitationally or electro-magnetically bound systems like trucks or galaxies. I'm not shrinking. You're not shrinking.

Space is thought to be expanding on the largest scales due to observations of distant galaxies.

The current theories relating to the 'expansion of space' and the 'Big Bang' are well accepted by the scientific community. Even Hoyle (who hated the Big Bang 'til his dyin' days) was able to deduce the nucleo-synthesis of atoms heavier than hydrogen and helium because he also observed the expansion of the universe. (Hoyle's 'mistake' was only that he thought matter was generated somewhere in space in a 'Steady State' universe - it was later discovered the heavier atoms were generated inside stars.)

Somewhere (I don't know where the 'boundary' would be) this expansion effect (dark energy?) overwhelms gravity and the galaxies are observed to recede. I think astronomers caluclate for expansion even when they observe Andromeda, which has a net velocity towards us.

As far as I know, these observations are all really real.

But we don't know how space expands. Max Tegmark (I think) described Dark Energy as simply a name for our ignorance. It's even possible Dark Energy is nothing more than a slight misunderstanding of Gravity. But I don't think scientists anticipate any major problems with our concept that the universe is expanding... people like Brian Greene are on the cutting edge of stuff like String Theory and I've never heard them even suggest a problem with expansion.

I've never heard an 'expert' talk about light slowing down or matter shrinking either - but hey, I'm just a science fan, not a scientist.

Just my $0.02 - and I love to debate this stuff...





Going back to our rope, in the void...

We can imagine Fraser is in a bubble of space which *pop* becomes bigger--and at the same time Pamela's bubble of space *pops* too.

I don't imagine that any debris (or any particles) that share Fraser's bubble are suddenly rushing past - why would they?

But... what has happened to the rope?

I imagine the distance between Fraser and Pamela is larger. Light travelling between them is red-shifted. No problem.

Ok. I imagine that, because every 'bubble' of space along the megaparsec of rope has also *popped*, the net effect has overcome the electromagnetism of all the atoms that make up the rope, and the rope has stretched. There are a heap of atoms along that rope and they can each, all handle being stretched apart a little. One day, they'll be too stretched and the atoms will fly apart.

There's the Big Rip astronomers talk about.

We can probably observe a kind of rope stretching today - the filaments that make up the structure of the universe we see in things like the Sloan Digital Sky Survey.

Any good?

__________________
If something is in me which can be called religious then it is the unbounded admiration for the structure of the world so far as our science can reveal it... of the manifestations of the profoundest reason and the most radiant beauty, which are only accessible to our reason in their most elementary forms...
Albert Einstein

Wow, Steve. You know stuff! I have lots of homework, looking into the various theories: pops, space filaments, and space bubbles at the end of long ropes. I intend to spend quite a bit of time with your answer, but first...

Please everyone, bear with me while I get the following concept off my chest. What if the universe started out at its present size, absolutely filled solid with matter. Crazy? Well, it gets worse. The big bang (fizzle?) occurs, and matter starts to decay; to shrink. No expansion. The shrinking, decaying matter clumps and swirls around together, making slowly decaying galaxies all across the stable-sized universe as time passes.

From our perspective, or at least my pathetic perspective since I don't have any idea what I am talking about, the grid of space appears to be expanding. Our frame of reference seems stable, so we assume that it is space that is doing the changing. Matter would not have to decay (shrink) perceptably to make a HUGE megaparsec of space seem only 73.5 km/sec bigger. Maybe we wouldn't even notice since everything made of matter which we perceive shrinks too, except space!

This helps me with two troubling concepts in particular. Pamela, in the inflation show, was talking about the peculiar homogeneity (sp?) of space in all directions. This would not be as irksome if everything was already spread out across the stable sized universe. It is just the spaces between things that appear bigger. With any luck, the model also relieves us of Dark Energy. Again, with everything already out there, we don't need this mysterious (to me) force shoving it all apart.

I am trying to figure dark matter into my ridiculous unified theory, but I haven't.

Whew, thanks for listenting to this nonsense. Please, no one needs to waste time explaining all the ways this is a ridiculous concept. I know, surely it is like some kid asking why their dog can't be president of General Motors.

Out to Pamela and Fraser (I got the spelling right this time), thanks for the show. It even appeals to someone who knows as little as I do.

Hey CPMosh.

I know what you mean about the homogeneity and flatness of the universe. Alan Guth came up with 'inflation' to explain it... otherwise, working back from the expansion they see today, astronomers figured the universe should look heterogeneous and curved. Inflation always seemed a bit convenient and arbitrary to me--but if you google 'sonic waves in the cosmic microwave background' there is a bunch of esoteric research by really clever people - and they all seem perfectly happy. So who am I to worry?

Damien doesn't think any of it's real - he figures we're all a figment of his imagination! Something like that... Hi Damien.

Does anyone like the *popping* space bubbles? I wouldn't mind betting when/if they do figure out how space expands - it'll be some kind of quantum effect.

*pop!*

...oops, sorry, that was just my soda.

__________________
If something is in me which can be called religious then it is the unbounded admiration for the structure of the world so far as our science can reveal it... of the manifestations of the profoundest reason and the most radiant beauty, which are only accessible to our reason in their most elementary forms...
Albert Einstein

I am trying to understand the pop hypothesis.

To summarize, we have a megaparsec-long piece of straignt rope in an otherwise empty part of space. The question is, are the ends of the rope, with Fraser and Pamela hanging on, flying through their respective grids of space at 36.75 km/sec or are they stationary within their grids while the rope stretches? If the rope is stretching, at what connective level does it do so?

The pop hypothesis doesn't seem to rely on the length of rope at all. Each bubble is expanding irrespective of whether it is connected to another bubble, or lots of other space bubbles.

It seems that the pop theory has the expansion on the atomic level. This is somewhat confusing. I thought I understood that the electromagnetic force simply laughed at the inflationary force. Does this also mean that the planck length is inflating?

The rope can stretch on a variety of levels. The filaments of rope can pull apart or break. The molecules within the rope can separate from one another. The atoms within the molecule can pull apart into separate elements. The protons, neutrons, and electrons within the atoms can pull apart. The quarks and up quarks and down quarks can pull apart. I am sure I left something out. Where does inflation do its work under the pop hypothesis? It sounds like the current pop theory relies on the atoms falling apart.

Here I go again with another ridiculous example. What, instead of the rope, a whole bunch of fist-sized stones were found in a tremendous line. The stones are touching each other and in a megaparsec-long straight line. Is there expansion in the chain? Where is it? Do the stones get further apart? The stones are only touching; no glue. There is nothing to resist tension. Do the stones break apart over time as the molecules fall apart? Do the elements within the stone disassociate? Does each stone grow slightly larger and less dense as the atoms get bigger? Do the parts of atoms get bigger? Do the spaces within the atom get bigger?

Do the forces within matter which usually laugh at expansion eventually grow exausted and submit to the pop?

I think Fraser and Pamela are stationary with respect to their local space ('bubble' of space as I imagine it)--just like the Milky Way is. At least as far as expansion is concerned--we're not considering spin or tidal forces or any of that good stuff.

If we think of our rope as just atoms, not molecules and all that complicated chemical stuff, I think it stretches at the level of the electro-magnetic bond between atoms--which is why I think we can compare it to the concept of the Big Rip--at some time in the distant future the atoms fly apart when they can't stretch no more. I think this is kinda comparable to the red-shifted light astronomers observe--when you think about it, photons are the force carrier of electro-magnetism, and light is photons too... my thinking is that the electromagnetism, like light, just gently stretches to accomodate the increase in distance. Red-shifted light, at least, we already observe.

I think all this would look nice and soft and gentle to an observer if we could see the whole length of the rope at once (which we can't because of relativity). I think if we consider how long the rope is, compared to how much it stretches - it's a tiny percentage. I reckon the entire observable universe expands about one ten thousandth of one percent over a whole year. So in other words - our rope ain't expanding much. We could stretch a rope ourselves that much right here on Earth, and you and me are only very small regions of quarks, gluons, electrons and photons.

The universe is expanding everywhere, all at once, except where gravity (mainly gravity because it is a force that acts at a distance, but also the other forces I suppose) is holding it back. I'm dividing up space into bubbles to help me imagine what might be happening where Fraser is, and where Pamela is. We could imagine dividing space into bubbles up and down the entire length of our rope, and suppose that they are all expanding simultaneously.

Not even on the atomic level perhaps? It's space (spacetime) that is said to be expanding, so in other words the 'background' on which all particles and forces exist - I'm thinking more of red-shifted light now, which is a real observable phenomenon.

Remember - I don't think nature really has to worry about actual megaparsec ropes 'cos they don't exist.

Space is the background - but it also interacts with particles and forces, for example via electromagnetic fields. And, I'm thinking particles are also wave-like, and waves happily expand every day, just like at the beach. And we know that space happily bends and curves and stretches... General Relativity tells us so and we (well not me!) have tested it. Heaps. I suspect somewhere in all of that stuff, is the mechanism whereby space expands, whether its vacuum energy, virtual particles, dark energy or some screw-up with gravity. But we don't know.

On the scale of atoms, Frasers, trucks and galaxies - the 'normal' forces do laugh at expansion, 'cos after all, we aren't expanding, at least not in any meaningful way anyone has observed. On the largest scales, distant galaxies are all receding from each other, apparently due to the expansion of space between them. Astronomers see it through their telescopes. I think we have to go with that.

I don't believe the planck length is changing at all. The reason I don't believe it, is that I've never seen or heard of any evidence that it is. But I have often wondered, like you. I've concluded, even if it were changing, we wouldn't know, because any measure stick we could devise, would be changing exactly the same, and so would we.

The Big Rip hypothesises first galaxies, then solar systems, then planets, then atoms, then all matter... is torn apart by the accelerating expansion of the universe. Then time stops. Apparently. But it's all hypothetical. Like our rope. Try this link perhaps?

http://www.space.com/scienceastronom...ip_030306.html

The *pop* is just how I have imagined the expansion, 'cos I've never seen it myself. It could be smooth and classical. If it were quantized (we don't know) it could really be a *pop* from a certain point of veiw. To paraphrase Obi-Wan.

I don't know how we would line up our stones, any more than I know how we would make a megaparsec rope.

There are plenty of stones in space, but all the stones we can see are in our galaxy and wouldn't count. If a comet or meteor, or even a planet, somehow got chucked into an intergalactic void where there was no gravity (there would probably be some?) - I don't imagine that anything particular would happen to it any time soon.

We're much better off sticking with light.

I'd be more inclin