Just found this - incredible stuff!

[Dave2002]

I've not thought in detail about the so-called big bang for a few days.
I came across this - http://burro.cwru.edu/stu/advanced/cosmos_history.html

Even if it might not all be true (I have no way of knowing) it's almost unbelievable stuff.

One thing which I really can't get is the expansion of the universe. If this is isotropic, then I don't quite see how the universe can be dated.
If there was a big bang at some central point, then it would form the origin, presumably of both space and time. Perhaps the current understanding by some of the events at the "start" of the universe is that there is a time origin, but maybe no space origin.

[Bryn]

I've not thought in detail about the so-called big bang for a few days.
I came across this - http://burro.cwru.edu/stu/advanced/cosmos_history.html

Even if it might not all be true (I have no way of knowing) it's almost unbelievable stuff.

One thing which I really can't get is the expansion of the universe. If this is isotropic, then I don't quite see how the universe can be dated.
If there was a big bang at some central point, then it would form the origin, presumably of both space and time. Perhaps the current understanding by some of the events at the "start" of the universe is that there is a time origin, but maybe no space origin.

Hmm. That page was last updated nearly 7 years ago. I thought the current COWDUNG* was that the 'Big Bang' was more likely a 'Big Bounce'.

* c.f. Conrad Hal Waddington.

[Gordon]

The idea of the "Big Bang" is itself decades old, first suggested by Fred Hoyle who was a Steady State man anyway! It has been studied and has evolved into a much deeper concept since the 1950s, the "bounce" being one strand of that thread.

Whilst the idea of a spatial beginning is just about tangible for human experience to get some understanding of, the "beginning" of Time I find much more difficult and no book by the magi of the business [eg Hawking and Penrose et al] has ever given me any sensible insight. The Bounce idea seems like a fudge to avoid this issue. An extended Bounce could be seen as the multiverse notion where time pervades all [?] but the spatial domain gets quantised into mutually inaccessible [?maybe] regions. This universe could have been a belch out of another but that simply extends the origin problem further.

Time seems a different entity from space and is all around and inexorable [unless you are a photon] but Einstein says that an understanding of the world can only be improved by considering them as "equals", at least mathematically.

I don't share Dave's difficulty with a spatial origin at a "point" because it does seem that the universe has a considerable degree of isotropy eg the MBR even though in its early stages it may not have been so uniform. The singularity has always been the bane of cosmology.

Who's to say that time flows at the same rate everywhere [it doesn't we know near massive objects] and wasa second at the beginning the same as a second today? If the origin was a very large concentration of energy [=mass?] then couldn't time naturally be at a standstill at that moment? Einstein implies that once space is finite then time must start to flow?

I'd be interested in what Vile Consort has to say on this one!

[Budapest]

Humans are like flies, trapped inside a room and bashing-up against a closed window until they die. In otherwords, us lot (humans) know diddly squat about anything.

What homo sapiens are good at is butchering themselves and other creatures and the planet we all inhabit.

Homo sapiens are a freak of nature who will become extinct sometime soon, and it won't be pleasant.

PM me if you want the number of your nearest branch of the Samaritans, or else...

[Pabmusic]

The idea of the "Big Bang" is itself decades old, first suggested by Fred Hoyle who was a Steady State man anyway! It has been studied and has evolved into a much deeper concept since the 1950s, the "bounce" being one strand of that thread.

Whilst the idea of a spatial beginning is just about tangible for human experience to get some understanding of, the "beginning" of Time I find much more difficult and no book by the magi of the business [eg Hawking and Penrose et al] has ever given me any sensible insight. The Bounce idea seems like a fudge to avoid this issue. An extended Bounce could be seen as the multiverse notion where time pervades all [?] but the spatial domain gets quantised into mutually inaccessible [?maybe] regions. This universe could have been a belch out of another but that simply extends the origin problem further.

Time seems a different entity from space and is all around and inexorable [unless you are a photon] but Einstein says that an understanding of the world can only be improved by considering them as "equals", at least mathematically.

I don't share Dave's difficulty with a spatial origin at a "point" because it does seem that the universe has a considerable degree of isotropy eg the MBR even though in its early stages it may not have been so uniform. The singularity has always been the bane of cosmology.

Who's to say that time flows at the same rate everywhere [it doesn't we know near massive objects] and wasa second at the beginning the same as a second today? If the origin was a very large concentration of energy [=mass?] then couldn't time naturally be at a standstill at that moment? Einstein implies that once space is finite then time must start to flow?

I'd be interested in what Vile Consort has to say on this one!

It was Georges Lemaître who first described what we now call the Big Bang in 1927. Fred Hoyle coined the (to him, derogatory) term in a radio broadcast in 1949, and it stuck.

As to your comments about time, we know (general theory of relativity) that time is a dimension of space, rather than a different entity. Or better put, time and space are different manifestations of the same thing, and are therefore inextricably linked. That's how you can postulate the (to me, very neat) notion that time came into existence with the Big Bang - so there was no 'before'. 'Before' didn't exist.

Very interesting post.

[Pabmusic]

I've posted this before, so forgive me if you've seen it, but this shortened form (still almost an hour!) of Lawrence Krauss's 'A Universe from Nothing' lecture is useful for understanding current thinking. It's aimed more at what the universe is, than how it began, but there's lots that is relevant:

http://www.youtube.com/watch?v=VdUYw59ztyw

It's at a book signing in La Jolla (if you know your Martinu).

[french frank]

we know (general theory of relativity) that time is a dimension of space, rather than a different entity. Or better put, time and space are different manifestations of the same thing, and are therefore inextricably linked.

I have a copy of Einstein and made less progress with that than with A Brief History of Time (must try harder), but does it capture the essence by thinking of space as 'horizontal' and time as 'vertical diemensions of whatever it is we're describing?

[I may transfer this to the new 'Ideas' section.]

[Pabmusic]

I have a copy of Einstein and made less progress with that than with A Brief History of Time (must try harder), but does it capture the essence by thinking of space as 'horizontal' and time as 'vertical diemensions of whatever it is we're describing?

[I may transfer this to the new 'Ideas' section.]

The 'Ideas' section would be good.

Have you read Brian Cox and Jeff Forshaw's "Why Does E=mc2?: (and Why Should We Care?)" - it's very good. You even forget D-Ream and 'Things can only get better' for a while.

[french frank]

Have you read Brian Cox and Jeff Forshaw's "Why Does E=mc2?: (and Why Should We Care?)"

I haven't, but will recommend it to a friend. We meet for lunch each month and he is constantly referring to this equation and posing the first question (rhetorically! ).

[Osborn]

The great physicist Richard Feynman, who can justly be called a genius, brilliantly explains relativity & derives & explores the great equation in a slim paperback 'Six Not So Easy Pieces' - transcripts of lectures given at Caltech. The companion 'Six Easy Pieces' is also brilliant. Eminently readable, intellectually dazzling. Everyone should have them!

[french frank]

The great physicist Richard Feynman, who can justly be called a genius, brilliantly explains relativity & proves & explores the great equation in a slim paperback 'Six Not So Easy Pieces' - transcripts of lectures given at Caltech. The companion 'Six Easy Pieces' is also brilliant. Eminently readable, intellectually dazzling. Everyone should have them!

I travel hopefully - Einstein's book was supposed to be written for the layperson ...

Have just looked it out:

The present book is intended, as far as possible, to give an exact insight into the theory of Relativity to those readers who, from a general scientific and philosophical point of view, are interested in the theory, but who are not conversant with the mathematical apparatus of theoretical physics. The work presumes a standard of education corresponding to that of a university matriculation examination, and, despite the shortness of the book [Hallelujah - Ed.] , a fair amount of patience and force of will on the part of the reader. The author has spared no pains in his endeavour to present the main ideas in the simplest and most intelligible form ...

[ferneyhoughgeliebte]

Have you read Brian Cox and Jeff Forshaw's "Why Does E=mc2?: (and Why Should We Care?)" - it's very good. You even forget D-Ream and 'Things can only get better' for a while.

Readers allergic to Prof Cox (the astronomer chappie, not the wonderful Social Historian) might prefer "E = mc2": a Biography of the World's Most Famous Equation by David Bodanis (Macmillan, 2000). Rather "gee whizz" in its approach and language (it was written so that Cameron Diaz could understand it) it nevertheless covers the whole equation (explaining "E" and the scientific history of the concept of "Energy"; "m" and "Mass" "c" and the speed of light; why "C2" and not "c3"; and how Einstein brought them all together) and left me believing that I had a much greater understanding of the subject.

[teamsaint]

When contemplating this kind or subject area, I always recommend this

http://www.amazon.co.uk/Punk-Science-Inside-Mind-God/dp/1905047932/ref=sr_1_1?s=books&ie=UTF8&qid=1351782523&sr=1-1

Its an easy read, and makes sense of a lot of stuff, to me at least.

Incidentally, if anybody has tried and failed with " A brief History of time" can i suggest just skipping the maths?
I got quite a bit out of it, if not everything that there was to be had, that way.

[Gordon]

It was Georges Lemaître who first described what we now call the Big Bang in 1927. Fred Hoyle coined the (to him, derogatory) term in a radio broadcast in 1949, and it stuck.

You are quite correct about Lemaitre of course. Hoyle however did put the notion to the public at large in those lectures/talks on the Third Programme way back and, because he was a Steady State man, he did not accept it. [Aside, with tongue in cheek: Big Bang was the result of Hubble was it not? So what if, at the Planck level where space is boiling with energy packets coming and going but apparently remaining in equilibrium, there was a small imbalance such that small amounts of space/matter were created incrementally everywhere so that the steady state actually does work?!? Bye bye Big Bang? What does Dirac have to say about that?].

.... time came into existence with the Big Bang - so there was no 'before'. 'Before' didn't exist.

Quite, just as there is no "outside" - unless you allow multiverses? I can't resist the idea that this universe is a hernia attached to something else!!

The universe doesn't expand into some unused region of pre-existing space, like a chemical or nuclear explosion, it creates space [3D] and time [4th D] as it goes. Just like electromagnetic radiation that needs both magnetic and electric components feeding off each other to propagate so space and time are mutually necessary.

It is these notions of no "outside" and no "before" that confound our human intuition, based on our experience at our scale of existence, and so renders it suspect when forming cosmological theories [or theories of the very small come to that]. Progress means asking the right questions and avoiding intuition.

Final point: if space and time are "equal" elements in an Einsteinian 4 dimensional basis for describing our universe how come "we" [ie humans or any material body] can travel freely in any one of 3 of them but not the 4th? Even photons have to travel at the speed of light [in the medium they are in]. Time isn't quite the same as space. Of course material bodies travel in time [with respect to some other frame] if they accelerate and reach relativistic speeds, they have no choice. It seems that although I can choose to move freely up or down, sideways etc I can't stay where I am in "space" and choose to move back a year, say, and then return at will. What is "still" in space anyway given we are moving through it in ways we can't really define, having no fundamental reference, only relativity.

[Serial_Apologist]

The problem is that it is inconceivable to think of nothing without invoking something.