I'm still trying to figure out alll this, and I am not very familiar with all the theories, so please help me out. According to many theories, our unkiverse is constantly expanding. Since people can not comprehend infinity, this theory makes sense. Forr the people that still can not comprehend infinity, but accept it, they will often leasd toward the theory that the universe is infinte. If the universe or "space" is expanding, what is it expanding into? Would matter be created during this expansion process? If matter was not created, then there would be nothing in the expansion, so space would be expanding, but it would be nothing expanding in nothing. How is this possible. since energy can not be created or destroyed, then how can the universe expand? Wouldn't this invlolve some sort of energy that does not exist because it is expanding into nothing?

Oh, by the way, I just noticed the other thread regarding universe expansion, but mine kind of asks different questions, so i'll look at the other one too, also how do we know for sure about the expansion. Its not like we can see it expanding or anything. Is there some equation that can prove this?

The `<b>red shifts</b>` of Galaxys are probably the best example that we have experimentaly, (the further away something is the more the light is `shifted` to-wards the red end of the spectrum), to show the universe is expanding.

But when ppl talk about the universe expanding, it`s not a `<i>normal everyday</i>` expansion...there is <i>nothing</i> that the universe is expanding <b>into</b>...

Perhaps it`s better to explain the expansion of space by imagining that all the particles/Galaxy's are <b>shrinking</b>...?

(<i>like the incredible shrinking man, we see everything getting further and further apart...</i>)

No I don't like that explanation because it suggest then that there is a constant absolute size of the universe which there isn't! It IS actually expanding and ILikeSalt is right. Its expanding into nothing. He is also right that it does take energy to expand space and this is one of the reasons why the universe is cooling.

the way i understood the expansion of the galaxy is that its happened many, many, many, many, many, many, many, many times. the "big bang" happened and it spread and spread until it couldnt anymore then it retracted again... it happend like this though. imagine spraying water with your thumb over the nozzle straight into the air while standing on a podium. the water goes up and out and falls around you. now think of a huge, super powerful vacuum underneath the podium that faces down. the water falls past you and then gets sucked back up. only the vacuum was really just a water pump, and you were merely spraying the water it was sucking up. an endless cycle... except that when you think of it in a spacial manner, all matter was originally in a cingularity... it spread out until acceleration stops, it falls back in on itself to create another cingularity until god says "BORING!" and starts another one.... if he exists... but i dont wanna get into that. "STICK TO THE F*CKING SUBJECT!"

@John Connellan
yea, my suggestion was a bit, er, radical...

But have you proof that the universe is not an absolute size...?
(er, apart from the <i>stretching</i>of light in the redshift that basically proves it..) ;)
i haven`t ever come across anything to say otherwise...

The universe is cooling BECAUSE it`s expanding.


(And, I personally think it`s expanding into nothing, BTW)

I think that it's more correct to say that it isn't expanding into anything.

I don't like that explanation because it suggest then that there is a constant absolute size of the universe which there isn't!
Unless it's infinite, of course.

@John Connellan
yea, my suggestion was a bit, er, radical...

But have you proof that the universe is not an absolute size...?
(er, apart from the <i>stretching</i>of light in the redshift that basically proves it..) ;)
i haven`t ever come across anything to say otherwise...

Its a nice analogy but I don't think it is real so it might confuse people even further. Basically I don't think it should be explained like that to people. It is of course, impossible to prove anything!

The universe is cooling BECAUSE it`s expanding.

Thats what I said :rolleyes:

(And, I personally think it`s expanding into nothing, BTW)

Thanks for your support ;)

I think that it's more correct to say that it isn't expanding into anything.

Nah, they're both correct scientifically. Grammatically is another thing! I said it like that so as not to confuse the people I was addressing. By saying it isn't expanding into anything some might take that as it isn't expanding. Know what I mean? :)

If expansion is taking place at every point of space, is it taking place inside the matter too, between the atoms that form this matter, or even betwen the elementary particules that form the atoms ?
In the common analogy of an inflating dotted balloon, nobody is speaking of the variation of size of the dots. Same for the fruit cake analogy : are the fruits inflating with the cake ?
If so, am I inflating with the radius of earth and the whole universe ? (so few in a lifetime). Maybe it is mesurable with the official meter (defined using a radiation wavelength, related to physical constants inside an atom) if it is not inflating too ? :confused:

I think the current consensus is...Yes.....u too are inflating at the same proportional rate as the universe. I don't know what proportional rate the universe is expanding at now, I'll have to Google it.

p.s. the official meter would be inflating too!

Bringing back blobrana's idea of shrinking... how do we know wheter the universe is shrinking or expanding? I'm not saying that the universe might be shrinking with everything getting closer. I'm thinking it as if the galaxies would be going appart and the universe would be "expanding", but the size of the universe to a external observer would still be the same. It's hard to explain what I have in mind. Ok...

Think of the universe as a balloon. The ballon is not expanding to an external observer. However, to an internal observer, the ballon is expanding. Things are getting farther and farther away. However, in reality, things are just getting "smaller" because the expansion is caused by the unwrapping of space-time. In other words: wrapped space-time looks like unwrapped one and instead of it being streching the fabric of space-time, it is actually unfolding.

Another way of seeing it. We are in a "black hole" inside another universe. This black hole had a singularity in its centre. The space-time was extremely folded (lots of space-time in a tiny bit of "space"). The singularity in this black hole exploded and it started to expand. For an external observer the black hole is not expanding. For an internal observer, the space-time is unfolding and expanding. We have the illusion that it is expanding into nothing.

This would result in a new kind of evolution: from stars to new universes.


I don't know. It's a crazy idea. But it's not bad to imagine it... ;)

Btw... this would explain the huge voids or "bubles" in our universe... :D

>>>>I think the current consensus is...Yes.....u too are inflating at the same proportional rate as the universe. I don't know what proportional rate the universe is expanding at now....

i don't believe so. the forces between particles is stronger than the universal expansion.

the way i understood the expansion of the galaxy is that its happened many, many, many, many, many, many, many, many times. the "big bang" happened and it spread and spread until it couldnt anymore then it retracted again... it happend like this though. imagine spraying water with your thumb over the nozzle straight into the air while standing on a podium. the water goes up and out and falls around you. now think of a huge, super powerful vacuum underneath the podium that faces down. the water falls past you and then gets sucked back up. only the vacuum was really just a water pump, and you were merely spraying the water it was sucking up. an endless cycle... except that when you think of it in a spacial manner, all matter was originally in a cingularity... it spread out until acceleration stops, it falls back in on itself to create another cingularity until god says "BORING!" and starts another one.... if he exists... but i dont wanna get into that. "STICK TO THE F*CKING SUBJECT!"


I have often fallen back to this conclusion various times. I first based it upon the number line with the expansion/shrinking ranging from the postive side to the negative side. It's not as good as an analogy because of the 2D limitation, but it still gets the point across. "God" must of really been bored, aye? :bugeye: ;)


fred

I think the current consensus is...Yes.....u too are inflating at the same proportional rate as the universe. I don't know what proportional rate the universe is expanding at now, I'll have to Google it.

p.s. the official meter would be inflating too!
I believe the latest result from the WMAP for the Hubble constant was 71+/-1...

i don't believe so. the forces between particles is stronger than the universal expansion.

It doesn't matter what forces are present in the universe. Forces act through space so if space is expanding then the particles will expand too along with the distance between them.

Boris2 is correct. Local electromagnetic forces (and even gravitational forces in some instances) oppose the universal expansion on local scales.

If humans, for example, participated equally in the expansion of the universe, then we would not be able to perceive the expansion.

We would not be able to perceive the expansion anyway :confused:

Boris2 is correct. Local electromagnetic forces (and even gravitational forces in some instances) oppose the universal expansion on local scales.

If humans, for example, participated equally in the expansion of the universe, then we would not be able to perceive the expansion.
Electromagnetic?!? I thought that was only strong enough in small scales... :confused:

Still, there are gravitational forces in local scales. For example, Andromeda is getting closer, and we are going in the direction of Virgo. So... I guess we see blueshifts when we look at those. If there are always blueshift in local scales, would the universe really be expanding? Or is the expansion just an illusion?

Also, another possibility. Just as in stars we have hydrostatic equilibrium with the net gas pressure and gravity, we might have a "doppler equilibrium" where the forces that expand the universe and causes redshift are as big as the forces that causes blueshift. In this scenerio the universe would have a definite constant size, and it would probably be rotating.

Have U heard of the moon going away from earth. It must be the same reason – the centrifugal force. The universe must be rotating at a point and hence everything is falling out. To prove this we should look if the expansion is at a equal rate in all direction or not.

The reason that this must be possible is that it is observer that the rate of this expansion is also increasing ie. The expansion is accelerating.

check this out http://www.sciforums.com/showthread.php?t=34490

Have U heard of the moon going away from earth. It must be the same reason – the centrifugal force. The universe must be rotating at a point and hence everything is falling out. To prove this we should look if the expansion is at a equal rate in all direction or not.

The reason that this must be possible is that it is observer that the rate of this expansion is also increasing ie. The expansion is accelerating.

The Moon's distance from Earth has increased steadily since it was formed; the generally accepted explanation for this, though, is that angular momentum from the Earth's rotation is transfered to the Moon's orbital motion. This is to balance the slowing of Earth's rotation by friction resulting from lunar tides.

If the Moon's centrifugal force was greater than its gravitational bond with Earth, it would not be in a true orbit, and before long break away.

The expansion of the Universe does not seem to be fastest along an "equator," as it would be in the case of your centrifugal expansion model. You're right, though, that the expansion seems to be accelerating.

Why all your post have links to other posts? :D
Anyways...
Have U heard of the moon going away from earth. It must be the same reason – the centrifugal force. The universe must be rotating at a point and hence everything is falling out. To prove this we should look if the expansion is at a equal rate in all direction or not.
It is. The Hubble constant says that as we look further back in time, the expansion is accelerating. The trick is how we interpret this. That does not necessarily mean that as the distance increases the expansion increases, because we are looking back in time, through the fourth dimension. Another possiility is that the universe is rotating, and we get the illusion of the expansion. Back to the ballon, we would be looking in a perpendicular angle, in the direction of the big bang. We can't see how things look like right now because light is not fast enough to bring us the information at the present stage, The trick is to recognize wheter it is expanding, contracting or simply rotating. If all the blueshifts and redshifts add up, then the universe is actually rotating. If you graph the Hubble constant relation plotting the speed and the distance, you will see that it exactly matches a solid body rotation.

As far as we go, we interpret it as the universe expanding. We see all the galaxies going away from us, but it is actually us going away from them, because we are in the present and they are in the past.


The reason that this must be possible is that it is observer that the rate of this expansion is also increasing ie. The expansion is accelerating.

Btw... I can't see how it can be accelerating. If the universe is flat, I would guess that the speed should be constant... :/

The expansion of the Universe does not seem to be fastest along an "equator," as it would be in the case of your centrifugal expansion model. You're right, though, that the expansion seems to be accelerating.
Huuuum... the universal equator... :D
Anyways... why would the universe do that anyways? How would the universe rotate? Could it rotate like the sun?

Anyhow... all that I know about centrifugal is when it comes to washing machines... :D :D

Even if the Universe as a whole - not just our observable part of it - is spherical in form, I don't see why it would be rotating. Everything from planetary satellites to spiral galaxies is believed to possess axial rotation because the way they formed, condensing from previously-rotating gas/dust clouds. The Universe originated the opposite way, exploding outward from a dense original state. Does an explosion rotate?

Even if the Universe as a whole - not just our observable part of it - is spherical in form, I don't see why it would be rotating. Everything from planetary satellites to spiral galaxies is believed to possess axial rotation because the way they formed, condensing from previously-rotating gas/dust clouds. The Universe originated the opposite way, exploding outward from a dense original state. Does an explosion rotate?
I would guess it depends on the mass and gravity of all the objects in the universe. It is hard to say that the entire universe behaves in the same way as its parts. I mean... galaxies behave completely differently then stars and solar systems! Their rotation is completely different. Just because the universe might be an explosion, that doesn't mean that it might not be rotating.

Also, if you see it as an spiral expansion, it would probably rotate, eh? :D

And maybe the redshift and blueshift only means that the universe has a constant size and it is rotating, wheter then expanding. Andromeda is coming towards us, and we are going towards the Virgo supercluster. And the Virgo supercluster might be going towards something else. If the universe is spheric and those blueshifts continues to go on and on, in the end it will make an entire turn around the universe, which would mean that the universe is rotating. ;)

TruthSeeker wrote: Or is the expansion just an ilusion ?

I would be inclined to agree with that statement. Yes it is true that we are moving towards andromeda, and the local group of galaxies (I beleive there is 6 including andromeda) is moving toward the virgo cluster.
Yes it is quite posible the expasion is an illusion. I remember reading that Edvin Huble,who discovered the redshift insisted all his life that the redshift should not be interpeted as a dobler effect. but only as a distance indicator.
Regards APOLO

Cool! This is at least the third time I've thought like a genious!
...17 more and I'll be considred a fully genious... :D

Please, don't pet my ego... :D

But wait... wasn't Hubble the one that found the Hubble constant and plotted the distance and speeds of the galaxies? :confused:

Truthseeker:

If you really want to be considered a genius, a good first step would be to learn how to spell the word.

Truthseeker:

If you really want to be considered a genius, a good first step would be to learn how to spell the word.
Hey! Chill out dude! I was just making fun of myself... :D
...and of my inherent capatibility of processing data within a series of instructions in my brain, through electromagnetic charges and hormones such as endorphin, serotonine, testosterone, and morphine!!! :D :D

TruthSeeker wrote: Or is the expansion just an ilusion ?

Yes it is quite posible the expasion is an illusion. I remember reading that Edvin Huble,who discovered the redshift insisted all his life that the redshift should not be interpeted as a dobler effect. but only as a distance indicator.
Regards APOLO

If such a radical departure from accepted modern cosmology should prove to be true, it would require a complete overhaul of astrophysics in general; decades of theorising rubbished! I do not relish such a prospect; but then neither did the Rennaisance theologians whose cosmology was challenged by Copernicus & Galileo. :eek:

Just suppose the Universe is not, after all, expanding: would we have to revert to Einstein's original version of the cosmological constant, to explain why it doesn't collapse under its own gravity? And perhaps even ressurect Fred Hoyle's continuous creation theory, to explain how a cosmos of baryonic mater can be infinitely old? :bugeye:

Just suppose the Universe is not, after all, expanding: would we have to revert to Einstein's original version of the cosmological constant, to explain why it doesn't collapse under its own gravity? And perhaps even ressurect Fred Hoyle's continuous creation theory, to explain how a cosmos of baryonic mater can be infinitely old?
I might be able to give some insight n the first comment. The other comment are completely strange to me.

Why doesn't the solar system collapse on its own gravity? Simple, because while the planets are moving towards the sun, they are also moving in a tangential direction. And that's why they have a circular motion, right? In the same way for the universe, the redshift would be a sign that the stars might be moving away from the center but at the same time the blueshift move them back, and we have once again the circular motion. So if the universe, the principle would be the same and the only difference would be the direction of the movements ;)

Expanding into nothing?

Well sir, you seem sure of yourself (really sure of 'them'), what is this "nothingess". it couldn't possibly be 'the ether' could it?!

Huh.... Mr... ehhh.... that discussion is long gone, ya know? :D ;)

Hi TruthSeeker
Yes you might be considered a genius 10 years from now when
thw BIG BANG theory goes down the drain.
Aside to STARTHANE XYZTH yes we will eventualy revert to Fred Hoyle's steady steady state theory as the only one that makes sense.
In essense the BB theory says that there was an absolute beginning and there will be a cold death end to the universe.
I have just finished reading Bryan Green's "THE FABRIC OF THE COSMOS" and though he is a fan of the BB theory He spends 522 pages explaining the string theory, which leads to the theory of branes whichh in turn leads to the conclusion that there realy is no beginning or end to the cosmos. It is (according to Greene) just a creation and recreation of different universes. including the one we live in. In other words a no absolute beginning or ending, but in a round about way. not realy different from Fred Hoyle's steady state..
theory.
For anyone who is interested ($56.00) I recomend reading A DIFFERENT APPROACHT TO COSMOLOGY by F.H. puplished in Jan. 2001 6 monht before Hoyle death..

I cannot resist adding a humourus not to this post. In August 2001 when Fred Hoyole's funeral was taking place in London, a friend of mine was in London on a buisiness trip,
and when he was registering at the hotel desk, he notised several famous astronomy names on the register. so he asked the name of the person standing next to him his name, it was Carl Sagan, so he said, you people have been batling Hoyle all your life; why are you here for his funeral? The answer
"we just want to make sure he is dead"
regards APOLO

I might be able to give some insight n the first comment. The other comment are completely strange to me.

What I meant by maintaining a baryonic Universe: to allow for a predominance of matter over antimatter, there must be some violation of what physicists call baryon number order, a fundamental property of protons and neutrons. This means, (for reasons I'm not 100% clear on) that protons are unstable, and will decay with a half-life of maybe 10^38 years - becoming positrons, neutrinos and gamma-ray photons. In an open Universe, all protons will, eventually, decay, and no coherent matter will remain - not even single atoms.

If spacetime is infinitely old already, there must be some mechanism continuously creating new protons (and neutrons). Otherwise there could be no galaxies, stars, planets or atoms in the Universe today!

What I meant by maintaining a baryonic Universe: to allow for a predominance of matter over antimatter, there must be some violation of what physicists call baryon number order, a fundamental property of protons and neutrons. This means, (for reasons I'm not 100% clear on) that protons are unstable, and will decay with a half-life of maybe 10^38 years - becoming positrons, neutrinos and gamma-ray photons. In an open Universe, all protons will, eventually, decay, and no coherent matter will remain - not even single atoms.
Oh! I know that! I didn't know it had a name! :D
Wasn't the lifetime of a proton 10³⁰ years??
Or there has been more studying to make it more accurate?
Protons can't really be called "unstable". I mean... their half-life is 10³⁸ years! Seems pretty stable to me. But I understand what you are saying. We can't have matter as we have when all the protons decay. However, the universe won't suddenly disappear either. The universe can have an infinite lifetime eventough everything decays some day. Maybe someday we will have an empty universe, but that doesn't mean that it doesn't exist anymore. As far as I know, space-time never decays. ;)



EDIT: Opps... forgot this part...
If spacetime is infinitely old already, there must be some mechanism continuously creating new protons (and neutrons). Otherwise there could be no galaxies, stars, planets or atoms in the Universe today!
Then I guess it is not infinitely old yet, eh?
What it means to be infinetely old anyways? Also, if we are considering that the universe is rotating, there should be an energy capable of doing that. Also, since the universe is rotating, this rotation might be creating energy and maybe, let's say... reviving the protons? :D I don't know.... the universe is weird anyways...

Expanding into nothing?

Well sir, you seem sure of yourself (really sure of 'them'), what is this "nothingess". it couldn't possibly be 'the ether' could it?!

What is the problem with people?! :D

If nothingness was ether (or even 'something') then it wouldn't be nothing would it? Think about it!

i don't think that the cmbr shows a rotating universe, neither do i think that the big bang theory will be abandoned in the near, or far, future. there are not many supporters of hoyles steady state unverse.

i don't think that the cmbr shows a rotating universe, neither do i think that the big bang theory will be abandoned in the near, or far, future. there are not many supporters of hoyles steady state unverse.
My math teacher once said "Math is not democratic." If 25 people say that 1+1 is 5 and 5 people say that 1+1 is 2, the 5 people are still correct. The same is in Physics, Astronomy, in the universe, basically. Just because most people support the big bang, that doesn't mean that that hypothesis is right.

Scientists often spend too much time banging their heads on the window, until someone opens the it and they finally fly away... :D

If you can ascribe any sort of noun or 'description' to what you consider "nothing" than it obviously has an existence does it not?

Tell me, how can something be seperated from existence?

My math teacher once said "Math is not democratic." If 25 people say that 1+1 is 5 and 5 people say that 1+1 is 2, the 5 people are still correct. The same is in Physics, Astronomy, in the universe, basically. Just because most people support the big bang, that doesn't mean that that hypothesis is right.

Of course. I also think that Big Bang model won't be abandoned in the near future - not because of its popularity, but because of its internal consistency, robustness, and supporting observational evidence.

I think that the BB model is popular because it's very close to the truth, not the other way around.

If you can ascribe any sort of noun or 'description' to what you consider "nothing" than it obviously has an existence does it not?

Tell me, how can something be seperated from existence?

No. I can name a word God but that doesn't mean he has to exist. As humans, we have the ability to put words to anything whether they exist or not which allows us to talk about the idea. Certainly, ether cannot be nothing!

Of course. I also think that Big Bang model won't be abandoned in the near future - not because of its popularity, but because of its internal consistency, robustness, and supporting observational evidence.

I think that the BB model is popular because it's very close to the truth, not the other way around.
Newton was pretty popular too, for many centuries! And the BB is very new compared to Newton's ideas. Yet, Einstein came along and proved both Newton and Galileo to be wrong in some of their ideas that were thought to be right.

You can't say for sure if it is very close to the truth or not. What we have is data. The trick is to interpret the data correctly. There is no real answer. At least not yet....

Boris2 wrote: Not many people still beleive in Hoyles steady state theory.

You will be surprised Boris. Apart from Hoyle several other qualified scientists ccme to mind, Geoffrey Burbidge, Jayant V. Narlikar, Halton Arp And many others. The reason the Steady State (SS) theory has a hard time gaining acceptance is that there are too many Nobel loreates and PHD's who has become famous because of amendments and explanations they have added to the Big Bang (BB) theory in order to explain inconsistensies in the theory. F.ex. When it became obvious that the universe could'nt look the way it does today according to the original BB theory. Some one said: now if we just asume that there was a big inflation in the speed of expansion shortly after the big bang, this inflated speed (greater than the speed of light) went on for some years, and then the speed slowed down to just the right amount we see today. But no one can explain what caused inflation to start at just the right time to suit the BB theory, or why it slowed down again at just the right time? or for that matter what was the cause that made a point of zero dimention blow up and create all the atoms (more than 10^84) that makes up all the galaxies we see today. There is abslutely no proof of any of this, someone just said so and people beleived him.
You might say, but the MBR of 2.8 degrees K is the radiation left over from the BB, and that proves it. It doesn't prove a darn thing, again just someone said it did and most people beleived him.
It is natural that there should be a simple low background temperature in space that would be none zero, and 5 astronomers worked on this betveen 1895 and 1904 (I havent got their names here but I can look them up) they calculated this temperature, and in 1904 came up with 3.0 K
this is 0.02 K within the actual temperature found experimentaly in the 1960s. I think this is a marvelous feat
by these scientists but it has nothing to do with leftover radiation from the BB. and those scientist ought to get equal recognition with Pezias and Wilson who proved their calculations to be correct 60 yers later.

What it comes down to is; if we chose to beleive in the BB theory ( A beginning and creation ex nihilo) rather than the
SS theory (no beginnig and no ending) we cannot do so unless we mention the word GOD. And scientist dont like to do that.

1. I disagree with the god explanation, it could be a very rare natural event. it's very stupid to apply some god idea to a natural universe :) at least imho

2. I find the rotating universe idea with no banging beginning a very interesting theory and it somehow makes more sense than the unexplained big bang blast, but how do you explain red shift then? Because it somehow points out to a huge event a particular period of time ago of what is now thought as the begining of our universe.

3. To return to the BB theory I have a question: what to your mind would make a singularity unstable? (of course it is possible that there was no singularity and all came just very very close together and then expanded), but still I place my question.

4. Is it possible that if a singularity blew inwards it could greate an infinite universe within a finite black hole or some other more weird formation in another universe. and if the black hole universe would cease to exist the newborn universe would still continue to exist, because it was outside of the originating universe and the black hole there was nothing more than like a scar. An infinite multiverse in time but not neceseraly in space.

If we for a moment imagine that we know that singularities can become unstable what could be the physics behind it?

apolo what you have posted has been posted in one form or another many times on the two forums i post to.

>>>Newton was pretty popular too.....

still is as far as i know. weren't the probes sent to mars guided by newtonian mechanics?

To Boris2

I have no doubt it has been said before. That proves others agree with my theory.

Yes newtonian mechanics certainly applies on a macroscopic scale, Einstein merely refined Newton's laws and added a few things that Newton could not possibly have been aware of, such as the fact that the gravety of a large object (a star or a planet)can bend light rays from a far away source.

To Avatar.

Point 1: No I dont beleive there was a GOD who said "let it be" I merely said, that would be the only way you can explain
creation out of nothing.

Point 2: The redshift? I have already explained in a previous post that I dont beleive the redshift is a doppler effect, i.e. it is not an indication of the speed of an object, ergo, the far galaxies are not moving away from us. So, THE UNIVERSE IS NOT EXPANDING.
The man who discovered the redshift Edwin Hubble wrote many papers and several books during his life time, and in all his publications exept one paper in 1929 does he insist that the redshift was not a doppler effect. Unfortunately later day scientists grabbed that 1929 paper and it has been copied in every astronomy book ever since.

Point 3 and 4 I cannot answer those, they are purely hypothetical, and when you get in to quamtum mechanics you can prove darn near anything

REGARDS APOLO

>>> That proves others agree with my theory.

doesn't make it correct, and the evidence shows that the steady state theory as stated by hoyle is incorrect.

>>>>(d). The linear velocity-distance relation was set out in a discovery paper in 1929, followed by a series of papers with Humason between 1931 and 1936 that verified and extended the relation to large (i.e. 60,000 km s[-1] redshifts. This discovery lead to the notion of the expanding universe which is the centre-piece (being the necessary condition) for the cosmological models of the present day.

http://antwrp.gsfc.nasa.gov/diamond_jubilee/1996/sandage_hubble.html

Looks like there was not one paper in 1929 but several up to 1936.

Hi Boris2

You are correct. The fact that others (including renowned scinentists) agree with me does'nt prove i'm right. Only that I'm not a lonely cracpot out in left field.
BTW what is the evidence you claim that prove Hoyle's SS theory is wrong?
Have you read Hoyle's last book, published in Spring of 2001
on his modified SS theory " A Different Approach to Cosmology

Re Hubble: yes it is the 1929 paper I refer to, the first one
on the redshift where Hubble says that he thinks that the redshift indicates both a dobbler effect and a distance indicator. but in subsequent papers and books he changed his mind, and he kept puplishing right up untill his death in the early 50s. But if you can print me a quote from one of his later publications where he says "the redshift is a dobbler effect". I will be interested in reading it. I'm always willing to admit a mistake.

If you and Avatar is interested in reading a book that explains the complete repudiation of the BB fiasco. You can order from amazon.com "Astronomy on Trial" by Roy C. Martin.
Published by university press of america in 1999. I have at least 10 other books on the same subject by well known scientists, but that one is a fairly easy read, only 235 pages, and not too much heavy math.

REGARDS APOLO

it is immaterial whether hubble thinks that the redshift is not a doppler effect. others have done the same and better observations since the '20s. and the BBT is still the one. it is up to you to prove to the nobel laureates and phds that the sst is correct.

If the redshift - increasing with distance - is not a doppler effect - then what DOES cause it? If it's merely the effect of light rising against gravity, then surely it would vary randomly across the sky dependent on how much mass is present along a particular line of sight.

If the redshift - increasing with distance - is not a doppler effect - then what DOES cause it?

The expansion of space itself. Think of this way, if the distance between two points where static a wave propagated from a star will arrive at the same frequency as that emitted. Now move the points apart so distance increases, light speed can not vary so the light increases in wavelength. It has no option.

If you maintin a constant rate of expansion object further away are moving away faster, so redshift increases linearly. OK, recent observations show the increase is not linear but that's the basics.

If it's merely the effect of light rising against gravity, then surely it would vary randomly across the sky dependent on how much mass is present along a particular line of sight.

Indeed, and this is why non-Big Bang theories have such a problem explaining Hubble Red Shift/Flow. All alternative mechanisms would not show homogeneous redshifts with distance.

Thanks, Thed - what I meant was, if, as Apolo said:

>>Point 2: The redshift? I have already explained in a previous post that I dont beleive the redshift is a doppler effect, i.e. it is not an indication of the speed of an object, ergo, the far galaxies are not moving away from us. So, THE UNIVERSE IS NOT EXPANDING...

then space will not be stretching, and the wavelength of light will not be increased as you suggested.

In a non-expanding Universe, how then does one explain the cosmological redishift?

Hi again Boris2

Let's face it. No one can prove with absolute certainty that either the BB theory or the SS theory is correct.
My reason for leaning toward The SStheory is; The BBtheory has so many strikes against it (it violates the law of cause and effect, and it violates Einsteins light speed limmit during inflation as well it uses many arbitrary asumpsions to try and make it fit the observations) so that takin on ballance, my sense of logic simply refuse to beleive it. And of couse the only alternative is the SS theory, which in my opinion has a lot fewer strikes agains it.
An example of one of the asumpsions made by the BBers is that "matter did'nt fly away at many times the speed of light during inflation, it was space itself that expanded at that speed". Now, if you chose to beleive that one that is your buisiness. As for me I think Einstein would turn in his grave if he heard that.

PS. On the redshift. Some scientists say it is caused by the COMPTON EFFECT and others say it is not. Take your choice.

REGARDS APOLO

the BB says nothing about "cause". it describes how the universe evolved, not what caused it to come into being.

the violation of light speed does not apply as it was an expansion of space. einsteins theories allow this to happen.

Hi Boris2

I know that the BB theory does'nt say anything about cause,
that's the problem !! The law of cause and effect is a well established law of physics. That's what bothers me -and others-that a theory can be build ignoring that law. If you or anyone else can explain to me, what is it that caused the explosion to start, what caused the explosion to accellerate to what we call inflation, what caused it to slow down at the right time in order for somebody to explain that the universe is today the way we see it.
If you can give me a reason why the law of causlity is violated in those times, please do.

Re Einstein; I have in my bookcase over 100 books on astronomy, about 10 relating to Einstein's theories. and although he talks a lot about the stretching of space around objects like stars to account for the fabrics of space to account for gravety, I have never seen any refference to the expansion of space itself on the scale envisioned in the theory of inflation. If you have any, please let me know.
As I've said before, I'm always ready to admit it if I've made a mistake

REGARDS APOLO

quote:
"In a non-expanding Universe, how then does one explain the cosmological redishift? "

Big Bang theories use three kinds of redshift;
(1) gravitational red shift, caused by the energy loss of EM radiation escaping a
gravity well,
(2) Doppler Shift, caused by velocity, EM radiation will be red shifted when emitted
by a receeding object and blue shifted when emitted by an approaching object,
(3) cosmological red shift, caused by expansion of the universe, as someone said, the EM waves will be 'stretched' as they travel through an expanding vacuum.
One problem is, how do you separate Doppler shift due to velocity from cosmological
red shift due to expansion? It is easy to determine the total amount of red shift, but
there is no reliable way to state that a certain amount of the shift is Doppler (velocity)
and a certain amount is cosmological (expansion). Theories could change and the red
shift would still be there, it would just be attributed to Doppler Shift and not cosmological expansion. Gravitational red shift is easier to separate because it is not
usually associated with whole galaxies, but intense gravational areas such black holes
and neutron stars. It is not even calculated for galaxies and all red shift is assumed
to be a combination of Doppler and cosmological. Gravitational red shift from Quasars
and black holes can be identified by the wide range of red shift comming from a point
source, the light is much more red shifted near the event horizon than it is farther out
on the disk. The current model of accelerating expansion and a 'flat' universe is what
the experts theorize based on their interpretation of data collected.
Special Relativity, as it was first presented by Einstein, was violated by the FTL
expansion of the universe because it contained no restrictions on distance. It is now
supposed to be used for 'local' space only, meaning like within our own galaxie. General
Relativity has never had any restrictions on FTL velocities. The Big Bang is now thought to have happened 'everywhere at once at a specific time' rather than the
older theory of beginning at an infinity (a point source) by most modern cosmologists.
Cosmology is rapidly changing, especially since the data collections of WMAP and SDSS.

newtons laws break down at high speeds and high gravity situations...is newton theory wrong? they still use it to guide space probes. the BBT is only designed for the evolution of the universe and it describes this better than any other theory. it does not matter how big inflation was, einsteins theories allow it to happen.

Boris, I do not understand your points. Maybe you could clarify?

the BBT cover the period from 10^-45 sec, i think, to present. i does not cover what caused the big bang. just as newtonian mechanics breakdown at high speeds and gravity situations. it is like asking why my sedan cant haul a 100 ton tralier like a truck can, it is not designed to do so.

http://hyperphysics.phy-astr.gsu.edu/hbase/astro/timlin.html

the big bang timeline. The BBT stops where quantum effects take over.

I never mentioned the 'cause' of the Big Bang. The Big Bang covers the period from
time'0' to the present, including inflation. Guth's model of inflation has been modified
by current observations and data collection. There is still an inflationary epoch, but
not from a singularity, a point. Special Relativity has nothing to do with inflation
or the Big Bang. The Big Bang was not envisioned by Einstein as a component of General Relativity either, he thought the universe was static as per the thinking of the day and even introduced the 'cosmological constant' to explain how it could remain
static. He later dismissed the cosmological constant as his 'greatest blunder' as the
universe was found to be expanding by Hubble. Special Relativity did not replace
Newtonian mechanics for predicting orbits of NASA's craft as orbits cannot be predicted by Special Relativity, that is the domain of General Relativity. Newtonian
mechanics are used by NASA because they are very accurate and relativistic speeds
do not come into play, so General Relativity is not needed. There are many inflationary
models, here is an updated list of parameters they must fit, along with some models that have been eliminated.
http://lambda.gsfc.nasa.gov/product/map/pub_papers/firstyear/inflation/wmap_inflation.pdf

Hi Boris2

I know that the BB theory does'nt say anything about cause,
that's the problem !! The law of cause and effect is a well established law of physics. That's what bothers me -and others-that a theory can be build ignoring that law.

The logic is really very simple. If the Universe is expanding, which the currently accepted model, then you can reverse the process. This implies all of creation came from a single point. That is an inescapable conclusion about expanding Universes. Why it was created is beyond current physics but it at least tells us there is a complete unknown yet to be discovered.

Worse still is a Steady State Universe (SS) for violating Physics. If SS is right there is no point of creation, the Universe has existed for all eternity. This is breaks the second law of thermodymanics which is held to be more sacrosanct than cause/effect. Also read up on Olbers Paradox.

If you or anyone else can explain to me, what is it that caused the explosion to start, what caused the explosion to accellerate to what we call inflation,what caused it to slow down at the right time in order for somebody to explain that the universe is today the way we see it.

Look up the Hawking Inflaton. It is a version of the Higgs Field that drives inflation and is carefully chosen to produce the visible Universe. This of course begs the question, where did that come from.

If you can give me a reason why the law of causlity is violated in those times, please do.

This is also a very hot topic in modern theoretical physics with numerous papers published each month. The feeling is that it is a side effect of Grand Unified Field theories. Look up Brane Worlds Intersecting and Ekpyrotic models.

Re Einstein; I have in my bookcase over 100 books on astronomy, about 10 relating to Einstein's theories. and although he talks a lot about the stretching of space around objects like stars to account for the fabrics of space to account for gravety, I have never seen any refference to the expansion of space itself on the scale envisioned in the theory of inflation. If you have any, please let me know.
As I've said before, I'm always ready to admit it if I've made a mistake

REGARDS APOLO

As 2inquisitive points out Einstein initially disbelieved the Universe was dynamic. Just because Einstein never initially thought about the issue or you have not read more on it does not make it (inflation) wrong. I take it you are not aware that the original cosmological models of the '20s where found to be seriously flawed by the '80s. Inflation is the fix to the problems and has been experimentally verified.

Suggest you read Alan H. Guth's book, "The Inflationary Universe" for a laymans overview of the theory and why it is now taken to be a valid model.

Zinnquisitive.
Thank you for the exelent post above.

Yes I'm aware of the resent amandment to the BB theory, that the explosion did'nt happened in one spot, but all over simultaniosly. I can't say that I agree with it. But I would like to quote Halten Arp,(aurthor of SEEIN RED) who was denied further acces to the Mount Palomar telescope, by the majority BBs because his observations tended to disprove the BB theory. In an interveiw on CBC radio he said "Yes, the BBs
keep comming up with new ideas and they try to fit them in to the BB theory even if they have to use a crowbar"

PS. Halten Arp left the USA a few years ago when he was offered a possision as proffessor EM at the university of Munic in Germany where he new resides. Apparently the Europeans dont mind peoples with contrary veiws.
REGARDS APOLO

The law of cause and effect is a well established law of physics.
I'm not familiar with that law. Can you explain it? With references, please.

Thed. I do admire your postngs, they are well thougt out.
I know about Olbers paradox. But what about "Ocams Razor?
REGARDS APOLO

apolo please give me your interpretation of occams razor...

ocams razor breifly says: If you have 2 or more theories trying to explain the same phenomenom, the simplest one is
almost always the right one.

Oh! "Ocams Razor" says that? Well thanks! I knew this before, my chemestry teacher said that long ago, but she didn't say who said that or anything. I talked about that some time ago in another thread and nobody understood me... :bugeye:

But anyways... now I know how it is called ;)

ocams razor breifly says: If you have 2 or more theories trying to explain the same phenomenom, the simplest one is almost always the right one.

Occam's Razor / Ockham's Razor:
one should not increase, beyond what is necessary, the number of entities required to explain anything

This doesn't mean that a more complicated explanation is wrong, only that it is unnecessary. As more phenomena are uncovered, an explanation that was previously justified by Occam's razor may fail, and a more complicated explanation may be required.

Note further that "explanation" is a twisty kind of word... often an explanation of an explanation may be required...

Apolo,
You seem to have missed my earlier question.
Can you please state the Law of Cause and Effect, and explain your statement that it is a universal Law of Physics?

Thed. I do admire your postngs, they are well thougt out.
I know about Olbers paradox. But what about "Ocams Razor?
REGARDS APOLO

Thanks, but I don't see what Occam's Razor has to do with this?

The Big Bang theory has very few axioms, the ones underlying relativity and an assumption that the Universe is expanding. From those few assumptions a very large number of, then unknown, facts where deduced. Even Fred Hoyle admitted the discovery of the cosmic background radiation was a blow for steady state. That's not including things like; H:Be ratio, Baryon:photon ratio.

Of more concern to BB proponents are things like,

<UL>
<li>Where the matter/anti-matter disparity came from. That is, why is there so little anti-matter. They both should have been made in equal amounts.
<li>What is Dark Energy? This is not predicted by any extent theorem. The current BB model has been successfull at predicting things, but not this.
</ul>

Ones I would add are,

<ul>
<li>What causes baryogenesis? It is supposed that quarks and hence hadrons are produced early, at around 10^-30 s or so. Could be off by a large factor.
<li>Just what causes the Instanton to be 'just so'. I've never liked magical factors in physics.
<li>What causes the anisotropies in the CMBR? I know it is explained as quantum fluctuations expanded by Inflation, but why are they there? The obvious answer is becase they are quantum based.
<li>A related issue, why the large scale structure (inhomogeneities) that are observed? Current explanation is the Universe is homogeneous on large scales. But we have no hard proof as yet.
<ul>

Woops, dupli-post. For some reason the submit form was still visible 10 hours after pressing the rely button.

I read your latest post thed. And I think I've forgot to mention that Fred Hoyle no longer beleives his original SS theory (early 60s) is accurate. His modified SS theoy was last published in early 2001 by Hoyle, Bubidge and Narkikar,
"A Different Approach to Cosmology" I have'nt got the space to to print all the 355 large pages from the book here, beside my keeboard dos'nt have all the math symbols nessesary. but very breifly it says, that the universe (or at least the region we are a part of) goes through phases of partial expansion and partial contraction, but never back to a point. If anyone is interested in refuting his modified SS theory they will just have to read it. You can probably get it at a library, if you dont want spend the $56.00 it cost me. Personally I dont mind reading books I dont agree with, just to see if there is something new that may make me change my mind on SS. I read Guth book, but I found it more fantasy than beleiveable.I also read the latest by Brian Greene "The Fabric of te Cosmos". Also "The Accelerating Universe" by Mario Livio. So I'm very familliar with Everything about INFLATION, STRING THEORY and BRANE THEORY and the multyverses
But my sense of logic simply can simply not accept all the fancy and contrived explanations they come up with to maintain the BB theory.
It is true that Hoyle theory defies the second law of thermodynamics. But is it not possible to postulate that the second law does not apply on the large scale of the cosmos, just like Newtons laws does not hold at relativistic speeds?
At least one scientist, Brian Greene, is willing to admit that when a cloud of dust of high entropy comes together to form a star with low entropy, "appears" to violate the 2 law.
He tries to explain it, but it is a very contrived explanation.
REGARDS APOLO

But my sense of logic simply can simply not accept all the fancy and contrived explanations they come up with to maintain the BB theory.
It is true that Hoyle theory defies the second law of thermodynamics. But is it not possible to postulate that the second law does not apply on the large scale of the cosmos, just like Newtons laws does not hold at relativistic speeds?

I can see what you mean, Apolo: accepted theories become hardened into dogma, and scientists tie themselves in knots trying to maintain them in the face of mounting anomalous evidence. The old idea of a geocentric universe is the best analogy - Ptolemy & Aristotle built a workable model, so intricate and complex that it can be considered a product of genius. Just a shame that they were working from a basically erroneous foundation!

Perhaps a fundamentally new approach to cosmology will be needed eventually. How about several simultaneous big bangs, with their expanding ejecta overlapping; the interference pattern between the multiple shockwave-fronts might explain those famous ripples in spacetime, the slight variations in the CMB. The thorough mixing of originally distinct fireballs could also be a reason for the large-scale homogeneity of the Universe.

Let's not forget, though, that the overall picture of the Universe, as we can observe, still looks like it has expanded from a single point.

I read your last post Starthane Xyzth with interest. It is well thought out.I patickular like the sentence "theories tend to bacome dogma after a while, and scientists tie themselves in to knots trying to defend the BBt in the face of mounting anomalous evidence".
BTW the greeks debated the origin of the universe fiercely
and Aristotle -who was one of the Steady Staters - invoked the prnciple that "out of nothing, nothing comes. If the universe could not have gone from nothingness to somethingness, it must always have existed".I think his logic is flawless and I could'nt have said it better myself.
There is an interesting article in this month issue of the Scientific American. The headline says "String theory suggests that the BB was not the origin of the universe but simply the outcome of a preexisting state".
It seems to me, that some scientists are trying to back out of the BBt and in to something that is, if not exactly a steady state universe, but something that resembles Hoyles Modified Steady State theory, and a universe with no beginning and no end.
REGARDS APOLO

The headline says "String theory suggests that the BB was not the origin of the universe but simply the outcome of a preexisting state".
It seems to me, that some scientists are trying to back out of the BBt and in to something that is, if not exactly a steady state universe, but something that resembles Hoyles Modified Steady State theory, and a universe with no beginning and no end.

It's just that no-one can truly grasp the idea of a starting point to time itself - or how spacetime can have come into existence if there was nothing "before" - and no "Before" at all, any more than there is anything north of the North Pole. I suppose that's as counterintuitive now as it was to Aristotle. :rolleyes:

Your string theory, the interacting brane theory, chaotic eternal inflation and the oscillating Universe are all attempts to allow an infinite past, with a cosmos infinitely old. Whether or not it's true, people just feel more comfortable that way. ;)

Yes it's true that some people are more comfortable with a universe of no beginning. And the I expect there are an equal number who insist that everything must have a begining.

I remember some years ago the Pope came out and said, it was OK for catholics to beleive in the BB theory. His explanation was that the creation story in genesis was right,
it just happened the writers got some of the details, including the time factor of 14 billion years slightly wrong.

When I hear the church hierahcy tell their followers it is OK to beleive in a certain scientific theorry, I get suspicios.
There is a difference between, BELEIVE IN, and BELEIVE. The former means I take it on faith, the second means, the emperical evidence available to me tells me this or that theory is the correct one.
REGARDS APOLO
,

http://story.news.yahoo.com/news?tmpl=story&u=/afp/20040518/sc_afp/us_astronomy_space_040518201615&e=2

Ok I realise having an ever expanding stick would require all the matter in the universe to create it and more but ... if i could have a telescopic stick that could extend indefinately - would it poke the 'edge' of the universe and stop or would it continue into this nothingness? I always come back to this telescopic stick when I think of this question.

Peace

c20

If your eternally telescoping stick could somehow extend faster than the space containing it is expanding, the far end would eventually stretch right around the Universe and poke you in the back... :D although, from our 3-D viewpoint, the stick may have remained perfectly straight. :eek:

How would that work when trying to define the geometrical maths.

Surely there is no edge to anything. it must just go on forever. can someone please explain it to me.

thanks

c20

http://story.news.yahoo.com/news?tmpl=story&u=/afp/20040518/sc_afp/us_astronomy_space_040518201615&e=2
Why don't they try to measure how much dark energy there was in the beginning? It shouldn't be so hard? I mean.... they just need to look at quasars, right? :confused:

So if they find less dark energy then, than it is probably increasing, while if there was more dark energy then, than the expansion is probably decelarating? ;)

There is no expansion of the universe. The red shift of the light from distant galaxies is due to the "tire-light" effect. In this an old and forgotten theory. The wavelength of distant light shifts to longer wavelengths while at the same time the numbers of these photons increases. This maintains conservation of energy. Ultimately, the waves shift down to the level of the cosmic background radiation that Penzias and Wilson found to be coming from every direction of the universe, showing the universe extends far, far beyond what we can see with even the Hubble space telescope.

The orbiting Chandra X-ray telescope has shown that the expansion of the Universe received a kick midway through its life, about six billion years ago.
http://news.bbc.co.uk/2/hi/science/nature/3728341.stm

I think everyone will ask the same question....

Why the number of photons increase? ;)

http://news.bbc.co.uk/2/hi/science/nature/3728341.stm
The orbiting Chandra X-ray telescope has shown that the expansion of the Universe received a kick midway through its life, about six billion years ago.
Why? Does that make any sense? Are we interpreting the data correctly? Is there any other way we can interpret the data?

The data they obtained spans the time when the Universe slowed from its original expansion, before speeding up again.
Is the universe oscilating!? Is it a recurring process or it happened only once? :eek:

Many astronomers attribute the driving force behind this cosmic acceleration to the mysterious dark energy - a strange form of energy that acts like repulsive gravity.
Why would the universe have such an energy?
(It's interesting to ask the question "why" rather than the usual "what" and "how" ones... ;) )

it seems that the universe has shown yet another example of how complex it really is

edit: as I got it from the article the universe at first expanded, slowed down,then started "crunching", then by some unexplained reason it started expanding again and at an increasing rate.

I think everyone will ask the same question....

Why the number of photons increase? ;)

When Hubble first calculated the age of the universe by red shift, he found it to be not as old as the Earth. It was then that the "tired-light" hypothesis was proposed to make sence of this. But it was abandoned because no one came up for an explanation of why the light would red shift and to where the lost energy of the light would go. The lost energy had to be accounted for someplace because of the law of conservation of energy. The only logical place for the energy to go is to increased numbers of photons. And low and behold Pensias and Wilson found those photons.

it seems that the universe has shown yet another example of how complex it really is

edit: as I got it from the article the universe at first expanded, slowed down,then started "crunching", then by some unexplained reason it started expanding again and at an increasing rate.
What could have caused such thing? It doesn't make sense. Such an energy would have to come from an outside source. A parallel universe or something of the sort. Or maybe a star outside our universe? Either way. Cause if the "dark energy" is decreasing and suddenly increases, such an energy has to come from somewhere. It can't just appear. And it shouldn't be inside our universe, because otherwise we would need a trigger to that energy, and I can't think of anything tha could trigger the release of an invisible energy. Gotta come from outside... ;)

When Hubble first calculated the age of the universe by red shift, he found it to be not as old as the Earth. It was then that the "tired-light" hypothesis was proposed to make sence of this. But it was abandoned because no one came up for an explanation of why the light would red shift and to where the lost energy of the light would go. The lost energy had to be accounted for someplace because of the law of conservation of energy. The only logical place for the energy to go is to increased numbers of photons. And low and behold Pensias and Wilson found those photons.
Did they "found" those photons? Are you talking about the background radiation? Cause this raiation is said to be caused by the bigbang. Why would we believe that the number of photons increase when we can believe in the expansion of the universe? How would the number increase? They can't just appear, can they?

I understand that you think that the background radiation is caused by the additional photons. But I can't see how those photons would suddenly appear. Through which process would that happen?

And what about the redshift? Why would the light be redshifted, if not through expansion?

What could have caused such thing? It doesn't make sense. Such an energy would have to come from an outside source. A parallel universe or something of the sort. Or maybe a star outside our universe? Either way. Cause if the "dark energy" is decreasing and suddenly increases, such an energy has to come from somewhere. It can't just appear. And it shouldn't be inside our universe, because otherwise we would need a trigger to that energy, and I can't think of anything tha could trigger the release of an invisible energy. Gotta come from outside... ;)

The idea is that gravity was able to slow the expansion of the Universe, as one might expect, up to a point. Of course, mutual gravitation between 2 bodies varies with the inverse square of the distance - whereas dark energy has no such constraint. Eventually, therefore, the overall effect of gravitation became less than that of dark energy - and the expansion began to accelerate instead.

Can no one explain why my ever expanding stick would eventually poke me in the back? There doesnt seem to be any concrete evidence to support this claim.

respectfully

c20 :m:

Drawing a straight line on the skin of a hot air balloon would eventually lead you right round and back to where you started. The Earth's surface looks flat to us, but walking/swimming about 40,000 km in any direction will bring you round the World and back home.

Imagine that our 3-D Universe is the surface of a 4-D sphere - any direction in space remains confined to that surface, and can in principle circumnavigate the Universe. Call it a hypersphere: that's how many modern cosmologists envisage space. Your expanding stick would follow a given line around the hypersphere - straight in 3-D space, but curved in a 4th dimension which we can't perceive. Thus it would, in theory, return to your location from the opposite direction.

There is no proof of this spacial curvature, of course - no disproof, either.

Drawing a straight line on the skin of a hot air balloon would eventually lead you right round and back to where you started. The Earth's surface looks flat to us, but walking/swimming about 40,000 km in any direction will bring you round the World and back home.

Imagine that our 3-D Universe is the surface of a 4-D sphere - any direction in space remains confined to that surface, and can in principle circumnavigate the Universe. Call it a hypersphere: that's how many modern cosmologists envisage space. Your expanding stick would follow a given line around the hypersphere - straight in 3-D space, but curved in a 4th dimension which we can't perceive. Thus it would, in theory, return to your location from the opposite direction.

There is no proof of this spacial curvature, of course - no disproof, either.

Ah i see. Thank you. I need stuff in easy terms :) It was enlightening to know this was theory as well. I thought the curved thing was science 'fact' but had not been able to find anything that supported fact.
Your description makes a lot of sense.

Thanks again

c20 :m:

This may be slightly off (this) topic, but this morning on the radio news, I heard the anouncer say; "The scientists have now found evidence, that the universe is at least one billion years older than preiviously thought".

It is only one year ago that astronomers was very confident that they had finally pinned down the age of the universe to,
-not 13 or 14 or15 billion years, but exacly 13.7 billion years- so now we apparently have an age of 14.7 billion + years ? is this going to be the final estimate ?

The reason I'm posting this is, have anyone heard or read about this new estimate.? And if so, what would be your comment ? I only heard the tail end of the anouncement and did'nt get the name of the scientist(s) who came up with it.
REGARDS APOLO

>>>> is this going to be the final estimate ?

probably not. all these estimates would have error bars and be based on current knowledge. what the popular press reports sometimes bears no resemblance to what the scientists say.

"What the popular press says,sometimes have no relation to what sientists say"

Pardon me, but I have never seen a report in the press on scientific subjects that was'nt a quote from some scientist(s). Unfortunately I missed the name of the scientist who was quoted in this instance, that's why I'm interested in connecting with some one who might have heard it.
REGARDS APOLO

Can no one explain why my ever expanding stick would eventually poke me in the back? There doesnt seem to be any concrete evidence to support this claim.

respectfully

c20 :m:
By golly-molly, you made me imagine things...! :eek:
Ewwwwwwwww :D


EDIT: Note that my comment has nothing personal, just factual...

The idea is that gravity was able to slow the expansion of the Universe, as one might expect, up to a point. Of course, mutual gravitation between 2 bodies varies with the inverse square of the distance - whereas dark energy has no such constraint. Eventually, therefore, the overall effect of gravitation became less than that of dark energy - and the expansion began to accelerate instead.
Can the data be interpreted in a different way? For instance, if there's no expanion?