Help me understand..

paynesmanor · Post by **paynesmanor** » Fri Apr 13, 2007 6:37 am

I am having a hard time grasping the concept of using telescopes to look back to the big bang.

If everything started from one point in exsistance, how far has the earth traveled from this point of origin, and how long did it take?

Since there has to be billions (wild guess) of years of movement of the earth from it's creation point, to its present locarion. There would be trillions of years that we would be missing. I am almost certin the Earth was not traveling at the speed of light during this time.

Then there is the fact that there are stars as far as the eye can see in all directions. So those stars would have taken time to get where they are today, So how if they were all created at the same instant, could we possably be able to see back to the beginning? We all know that light travels very fast, So theoretically, no matter how one looks at the equation, they can only see the light emited from that star from a long time ago, and no where near the Big bang.

Please tell me where I am wrong!

Nereid · Post by **Nereid** » Fri Apr 13, 2007 12:23 pm

paynesmanor wrote:I am having a hard time grasping the concept of using telescopes to look back to the big bang.

If everything started from one point in exsistance, how far has the earth traveled from this point of origin, and how long did it take?

To one level of accuracy, the Earth has not moved at all ... it is inaccurate to visualise the expansion of space, as described by the equations of Einstein's theory of General Relativity (GR), as an explosion.

Also, modern cosmology theory gets increasingly uncertain the closer 'the clock' gets back to zero. In fact, the two theories at its heart - quantum mechanics and GR - are mutually incompatible in what is called the Planck regime. This simply means that we have no idea of what 'happened' in this regime.

Since there has to be billions (wild guess) of years of movement of the earth from it's creation point, to its present locarion. There would be trillions of years that we would be missing. I am almost certin the Earth was not traveling at the speed of light during this time.

To some observers - now a very long way from here - the Earth is moving at well above the speed of light! To us, on the Earth, we are not moving at all.

The two revolutions in physics, a century ago, quantum mechanics and GR, are full of counter-intuitive implications. However, they are the most successful theories in science ... ever.

Then there is the fact that there are stars as far as the eye can see in all directions. So those stars would have taken time to get where they are today, So how if they were all created at the same instant, could we possably be able to see back to the beginning? We all know that light travels very fast, So theoretically, no matter how one looks at the equation, they can only see the light emited from that star from a long time ago, and no where near the Big bang.

Please tell me where I am wrong!

I hope you now have a better understanding - the expansion of space is not an explosion.

hishadow · Post by **hishadow** » Fri Apr 13, 2007 4:29 pm

Nereid wrote:
paynesmanor wrote:I am having a hard time grasping the concept of using telescopes to look back to the big bang.

If everything started from one point in exsistance, how far has the earth traveled from this point of origin, and how long did it take?
To one level of accuracy, the Earth has not moved at all ... it is inaccurate to visualise the expansion of space, as described by the equations of Einstein's theory of General Relativity (GR), as an explosion.

Would it be more correct to say that it's the geometry of space that is expanding/stretching with time. I think the problem many people have a hard time thinking of this is that they visualize it as an explosion from a fixed point in space, and that matter is hurled away in all directions from this point, in a space with a static geometry.

One way to visualize it could be to take a elastic ball and draw an even grid (the geometry of space) on it. Then plot in some "galaxies" on the ball. As you pump (simulating time) the ball full of air it starts expanding and you'll see the galaxies drift further and further away from each other. Still, every galaxy is still in the same position when you look at the grid. Remember also that our 3-dimensional world is contained within the surface of the ball. Observing the surface of the ball expanding is analog to watching a 3-dimensional world captured on film and played back on a tv-screen.

If you deflate (rewind time) the ball, you move backwards to the beginning of time. As the ball gets smaller and smaller, the galaxies move closer and closer to each other until you reach a point where everything gets so dense that all matter turns into energy that gets infinitly hot, the start of the Big Bang. (Is this explaination right?)

Also, it's not given that the geometry of space is a ball. It may be infinite/looped/closed in any direction.

paynesmanor · Post by **paynesmanor** » Sat Apr 14, 2007 4:32 am

The earth is not moving? and has not moved? Umm we would be at the center of the big bang then?? Now I am totally confused,

To think of the universe as an expanding balloon, That is how I see the universe, except with a big explosion causing it to expand, Not like a nuke but more like a sparkler.

So perhaps I am missing something basic in astronomy, Is there a large void in the center? and the stars around the outer edge? I dont get it?

If it exploded, this would explain the hot stars, the roundness of the earth, as well as many of other parts of the universe...

our planet is just a drip of cooled burnt matter ziping through space in a direction unperceiveable to something so small as a human being.

Nereid · Post by **Nereid** » Sat Apr 14, 2007 2:43 pm

paynesmanor wrote:The earth is not moving? and has not moved? Umm we would be at the center of the big bang then??

That's correct.

And if you go out tonight, and look at the sky ... every single one of the stars you can see has also not moved (in the same sense that the Earth has not moved).

Look at one of the Hubble Deep Field images (example; every single one of those galaxies also has not moved, in the same sense.

The centre of the big bang is everywhere.

Now I am totally confused,

[snip]

I think the source of your confusion is that you seem to be still thinking of the big bang as an expLOsion IN space, rather than an expANsion OF space (and that's before we start to address expansion of spaceTIME, rather than just space).

As hishadow mentioned, a common analogy is the balloon one; one trick with this analogy is that our entire 3D universe is, in the analogy, just the 2D surface of the balloon. One drawback of this analogy is that you could, logically, ask where, in 4D, is the universe expanding from (as in the balloon analogy, the 2D surface expands from a 3D centre). It gets tricky to answer this question, while staying within the analogy.

Of course, if you were to study GR, and the cosmological models built using it, you'd see the strengths and weaknesses of the analogy more clearly.

Perhaps Ned Wright's Cosmology Tutorial might help?

craterchains · Post by **craterchains** » Sun Apr 15, 2007 1:37 pm

, , , of course nobody would want you to be deceived either as to the truth about such things.

makc · Post by **makc** » Mon Apr 16, 2007 11:20 am

@craterchain, mmm what? I think original post question is much more like "i want to understand BBT" than like "i want to know how true is BBT". and you?

paynesmanor · Post by **paynesmanor** » Tue Apr 17, 2007 5:02 am

[quote="makc"]@craterchain, mmm what? I think original post question is much more like "i want to understand BBT" than like "i want to know how true is BBT". and you?[/quote]

No My original question was, I am having a hard time grasping the fact that scientists think they can see back to the BB. Not that I don't understand it.. I just don't see the logic in it.

Just because things don't appear to be moving on our time scale, does not mean that they are stationary. Humans are condemed to percieve time in one sense, that which is based on the speed of the earth spinning around the sun. Step outside the box, and perceive time as a giant, who's foot would be the size of our visable universe. Things like the speed of light would appear to be no more then a slow snail.. Size would not be the only thing that matters when it comes to the perception of time, Things like If you lived on a planet where you lived to be a trillion * trillion years old, and one year was a trillion Earths years. Space would appear to be moving much faster when compared to our perception of time.

makc · Post by **makc** » Tue Apr 17, 2007 8:24 am

I am having a hard time grasping the fact that scientists think they can see back to the BB... I just don't see the logic in it.

Well, same on my end, I just don't see what's the problem with the logic in it. Assuming a) BB was there, and b) light is fastest thing in the Universe, it is reasonable to expect age of visible objects to grow according to the distance. Sun light is actually ~8 minutes old. Most of stars light we see are thousands of years old. And so on, and on, deeper look reveals older things.

craterchains · Post by **craterchains** » Tue Apr 17, 2007 9:27 pm

paynesmanor
Actually I think that is more of a statement, than a question.

Only by accepting that things can, and do, happen in our known universe that are mush faster than the speed of light can we begin to comprehend how our universe came to be in it's known form today.

Norval

Doum · Post by **Doum** » Wed Apr 18, 2007 5:02 am

Michael Mozina wrote:
paynesmanor wrote:I am having a hard time grasping the concept of using telescopes to look back to the big bang.
You are not alone.

http://www.thesurfaceofthesun.com/Alfve ... cience.pdf

Not alone but almost.

I still dont understand that electric plasma thing and i'm not alone neither. I read that link and i dont see any evidence at all that electric plasma can create galaxys or the universe as we see it. Less explain it.

Big Bang is a word use to vulgarise the creation of the universe but it does'nt mean that the universe was create. What science result show to the scientist is that the universe seem to originate from a single point. The more it goes the more it seem right. Now to me the redshift of the matter moving away ( Froms star or galaxys) is a scientific fact. And it show that the universe is expanding. If a galaxy is moving toward us the redshift will move the other way on a wavelenghtscan (Toward the UV.) and its a fact too. So the universe realy seem to have a beginning and the more we look far into universe the more we see the past of it. Of course as new science results gets in and new discoverys are made the theory will change with it.

If that sentence has any value then i also say " I'm not alone beleiving it."

Nereid · Post by **Nereid** » Wed Apr 18, 2007 3:21 pm

Doum wrote:
Michael Mozina wrote:
paynesmanor wrote:I am having a hard time grasping the concept of using telescopes to look back to the big bang.
You are not alone.

http://www.thesurfaceofthesun.com/Alfve ... cience.pdf
Not alone but almost.

I still dont understand that electric plasma thing and i'm not alone neither. I read that link and i dont see any evidence at all that electric plasma can create galaxys or the universe as we see it. Less explain it.

Big Bang is a word use to vulgarise the creation of the universe but it does'nt mean that the universe was create. What science result show to the scientist is that the universe seem to originate from a single point. The more it goes the more it seem right. Now to me the redshift of the matter moving away ( Froms star or galaxys) is a scientific fact. And it show that the universe is expanding. If a galaxy is moving toward us the redshift will move the other way on a wavelenghtscan (Toward the UV.) and its a fact too. So the universe realy seem to have a beginning and the more we look far into universe the more we see the past of it. Of course as new science results gets in and new discoverys are made the theory will change with it.

If that sentence has any value then i also say " I'm not alone beleiving it."

I should thank Michael for posting that a link to that document; I'd not read that paper before.

Curious that a paper about (modern) cosmology, written in 1984, includes not a single reference to the Hubble (redshift-distance) relationship ... or did I miss it?

Although it was not intended to present any alternatives to the big bang theory, it did mention two ideas that impinge upon some of the key tests - Olbers' paradox and the CMB. Of course, in 1984 Alfvén did not have the COBE results, so it was certainly still tenable to suggest that 'iron whiskers' could have generated the CMB. Today, that hypothesis is quite inconsistent with the observational results - the SED (spectral energy density, or distribution) is too close to a blackbody for it to be caused by spinning 'iron whiskers'.

More curious is the apparent inconsistency between the Charlier "infinite universe with a hierarchical organization" (as presented), the reported values of a, and Alfvén's comment ("It satisfies both the Olbers and Seeliger objection") ... unless a > 2, then the sky cannot be dark at night, so if de Vaucouleurs, Peebles et al., and Groth et al. found* a < 2, this kind of Charlier "infinite universe with a hierarchical organization" cannot be consistent with a dark night sky!

Or did I miss something? Michael, would you care to comment?

*Oh what a difference 20 years makes! This chart shows that the universe does not, pace Alfvén, have this kind of hierarchical structure.

Nereid · Post by **Nereid** » Wed Apr 18, 2007 3:25 pm

If you're still reading this thread paynesmanor, the net of the last few posts is that one of the alternatives to the big bang theory, promoted with great energy and enthusiasm via the internet ("electric universe", or similar), is not taken seriously by professional astronomers ... because it is quite inconsistent with good observational and experimental results.

BMAONE23 · Post by **BMAONE23** » Wed Apr 18, 2007 8:59 pm

The Hubble UDF image here http://antwrp.gsfc.nasa.gov/apod/image/ ... st_big.jpg shows some vastly irregular galaxies (presumably still in the early stages of forming) as well as some highly redshifted objects. Is there currently a way to measure the distance between these "Red" objects and determine if they are in fact vastly closer together than modern galaxies (as one might expect in an expanding universe)? Or perhaps even determine if ther are the same relative distance apart as closer galaxies are? If not, We will just have to wait for the OverWhelmingly Large Telescope http://en.wikipedia.org/wiki/Overwhelmi ... _Telescope to be built

harry · Post by **harry** » Fri Apr 20, 2007 8:20 am

Hello All

BMAONE23

said

The Hubble UDF image here http://antwrp.gsfc.nasa.gov/apod/image/ ... st_big.jpg shows some vastly irregular galaxies (presumably still in the early stages of forming) as well as some highly redshifted objects. Is there currently a way to measure the distance between these "Red" objects and determine if they are in fact vastly closer together than modern galaxies (as one might expect in an expanding universe)? Or perhaps even determine if ther are the same relative distance apart as closer galaxies are? If not, We will just have to wait for the OverWhelmingly Large Telescope http://en.wikipedia.org/wiki/Overwhelmi ... _Telescope to be built

We cannot assume the galaxies are in the early stages until there is evidence for it. If we do assume than we are assuming that the big bang theory is correct.

The lasrge telscope will give us some form of evidence.

========================================

paynesmaor
said

I am having a hard time grasping the concept of using telescopes to look back to the big bang.

If everything started from one point in exsistance, how far has the earth traveled from this point of origin, and how long did it take?

Why even look back and in what direction, You see 13.2 billion light years in one direction and the opposite the same. You find monster super clusters of galaxies and than you can question, How on earth did it ever form? The overal distance is 26 billion years and soon we shall see much more.

The earth only formed about 5 billion years ago. The estimate for the big bang is about 13.7 billion years.

=============================================

Nereid · Post by **Nereid** » Thu Apr 26, 2007 12:53 am

Michael Mozina wrote:
Nereid wrote:Curious that a paper about (modern) cosmology, written in 1984, includes not a single reference to the Hubble (redshift-distance) relationship ... or did I miss it?
I think he mentions Hubble's law several times, although I don't think he tries to address it in that particular paper.

I checked - just once (on p11).

The astonishing thing, which I only really discovered by reading the paper carefully, is that he does not, repeat NOT, cite the Hubble relationship as one of the pillars of the BBT!

Perhaps you can help me out here, Michael: why, in section 3.4, does Alfvén state "In fact, the Big Bang believers of today claim only two observational supports for their hypothesis" [the CMB and primordial abundance of light nuclides]?

Although it was not intended to present any alternatives to the big bang theory, it did mention two ideas that impinge upon some of the key tests - Olbers' paradox and the CMB. Of course, in 1984 Alfvén did not have the COBE results, so it was certainly still tenable to suggest that 'iron whiskers' could have generated the CMB. Today, that hypothesis is quite inconsistent with the observational results - the SED (spectral energy density, or distribution) is too close to a blackbody for it to be caused by spinning 'iron whiskers'.
If memory serves me, I think he used the term "iron needles" but I do share you sentiments. I didn't think it was a very convincing argument either. I've seen better.

Or did I miss something? Michael, would you care to comment?
Not beyond what I already noted. Obler's paradox is based on two basic assumptions, one of which is known to be false. There isn't much more to say about it as far as I'm concerned. It's actually based on a third assumption, specifically that an "infinite" universe is not in motion and it ignores the concept of general relativity and motion altogether. I think of the five arguments on your list, that is the simplest ones to blow out of the water.

You've lost me; I just don't understand this at all.

How does any Alfvénic cosmology account for Olbers' paradox, in all relevant wavebands of the EM spectrum?

In particular, given that Alfvén, in the paper you cited, is at pains to show that GR is of trivial import at sufficiently large scales*, and given that he seems to ignore the Hubble relationship entirely, how do GR and motion play to a resolution, in any Alfvénic cosmology?

Oh what a difference 20 years makes!
No doubt.

FYI, I do not understand why you think your graph negates Alfven's theories.

OK; let's look at this in more detail.

Please present a curve, in a graph with the same axes as the SDSS/Tegmark one, of a family of Charlier/Alfvén universes ... with a < 2.

Please state any additional assumptions you have made (beyond those made explicitly in Alfvén's paper).

*I'm also curious to see how you, or any other poster who reads this, can present a modern defence of the Alfvén statements.

paynesmanor · Post by **paynesmanor** » Fri May 11, 2007 4:29 am

Measurements of the afterglow of the big bang suggest mysterious dark matter was about six times more abundant than ordinary matter in the early universe.
http://space.newscientist.com/article.n ... news_rss20

Is the Big bang theory where everything was at one point. and then blew up outward? Tell me if this statement is wrong!, Perhaps this is why I am having a hard time understanding why so many people believe they can see back to the beginning of time.

So to say that they are looking back to the early universe, would be WRONG!.. As it took time for the earth to reach its present day position. So in fact they would be missing those trillion, trillion, years. WHY OMG WHY.. I understand why they think they can see back, as Light takes time to move, so for something to be so far away, it would take billions of billions of years for that light to reach us. But I guess the people that believe this still think that nothing can move faster then the speed of light. They need to think outside the box we call earth..

Nereid · Post by **Nereid** » Fri May 11, 2007 3:37 pm

Your short post contains many of the common misconceptions about the meta-theory called the Big Bang theory, and about General Relativity.

Let's see if I can address some of them.

The starting point for the class of (scientific) theories called (in shorthand) the Big Bang Theory (BBT)* is the General Theory of Relativity, often abbreviated as GR.

If we apply GR to the universe as a whole, and examine what happens using a coordinate called 'comoving time', we find that the universe - including all space and time - 'began' as a singularity.

However, as GR and the Standard Model of particle physics (the other foundation theory in physics today) are known to be mutually incompatible, we know that we cannot describe any regime in any universe where this incompatibility is severe. Such a regime is the Planck regime; in simple terms, it is one of extremely high density and temperature.

Cosmologically, this means any BBT can have scientific validity only outside the Planck regime. This means we cannot say - in any scientific sense - what happened 'before' the universe was ~1 Planck second 'old'.

Further, the Standard Model has only been tested up to a TeV or so in terms of particle energies. This means any BBT is not well-constrained at times earlier than when the average energy of the universe was ~ a TeV or so (I'm skipping over a lot of quite important detail here, but I don't think I'm doing too much damage to the relevant science by summarising).

That deals with the scope of BBTs, wrt the early universe.

As to the motion of the Earth (etc); one of the counter-intuitive things about GR is that an expansion of space-time is not motion, in the sense that we normally assume (and in BBTs, the universe - spacetime - is expanding). In this sense, 'nothing can travel faster than the speed of light' is misleading; the universe can 'expand' at 'speeds' much greater than c (and still be consistent with GR).

There are a number of good accounts - available on the web, for free - which explain this. Google on Lineweaver (he and Davis wrote a good article for Scientific American, which I think is available on his website; there's also a more technical paper available there).

*Note that it's not one theory, but a class of theories.

Starship Asterisk*

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