expanding universe question

jim77

Quote by skydivephil

The big bang theory which states the universe has been expanding for 13.7 bio years (according to latest measurements) relies not just on red shift but on four independent pillars of evidence.
http://physics.weber.edu/palen/Phsx1.../LBigbang.html
If you don't know what lensing or warps in sapce mean, or you dont understand inflation, I suggest reading some introdcutory astronomy texts as well as the FAQ here in cosmology forums.
A good text is this:
http://www.amazon.co.uk/Universe-Rog...ef=pd_sim_b_10

There is a consensus that the universe beganb expanding 13.7 bio years ago this is supported by the lines of evidence I linked to above. Yes I would agree that anyone that disputes that is considered a crackpot. However there is certainly a widely held belief that this picture is not wrong, but is incomplete and there may be a pre big bang history. This is currently being explored by cosmologists but no model is agreed upon yet because they haven't been tested. There are many interesting, creative and exciting ideas , this inlcudes a universe from nothing, but also includes many other ideas such as our unvierse bouncing from a previous one that contracted. But until some test can be devised and carried out they will not be considered facts in the same way the expansion history of the unvierse is considered a fact.

This is what I dont get. Brilliant scientists like Fred Hoyle and Halton Arp posit alternative theories and are labelled crackpots for their efforts. I cant understand the details (I have read a lot of introductory astronomy texts but without the the advanced math they read like a dungeon and dragons text on wizardry (just accept that this is so! Not criticising I just dont have the faculties to judge the merits of what I'm reading)) so I can only judge by my gut (Colbert will back me up on this) and these guys seem like honest scholars who look at the same evidence and come to different conclusions. You guys know better than me so I'll defer to you but is everything really so wrapped up?
sincerely

Lino

Quote by bapowell

Maybe that's a fine interpretation. It's just that the observation of a homogeneous and isotropic universe has nothing to do with expansion. If you add it to the other three, it does not strengthen the argument for a big bang.

Thanks Bapowel. Understood.

Regards,

Noel.

Reptillian1

Quote by jim77

Brilliant scientists like Fred Hoyle and Halton Arp posit alternative theories and are labelled crackpots for their efforts.

Well, these scientists are dethroned after scientists who takes into the consideration of the possibility they're right or willing to test it have shown that they're wrong. However, let me say this to you. Scientists who tries to find alternatives ideas being labeled as crackpots is nothing new as shown in history and a lot of time, the mainstream scientists in history fails to take into consideration that questioning and looking for new ways to look at our universe helps us develops more of our understanding. There is nothing wrong with questioning at all and in fact, questioning does help advancement rather than sticking to the same ol ideas a lot of time. Honestly, I appreciate that you can appreciate scientists who tries to look into alternative ideas.

bapowell

Quote by jim77

This is what I dont get. Brilliant scientists like Fred Hoyle and Halton Arp posit alternative theories and are labelled crackpots for their efforts. I cant understand the details (I have read a lot of introductory astronomy texts but without the the advanced math they read like a dungeon and dragons text on wizardry (just accept that this is so! Not criticising I just dont have the faculties to judge the merits of what I'm reading)) so I can only judge by my gut (Colbert will back me up on this) and these guys seem like honest scholars who look at the same evidence and come to different conclusions. You guys know better than me so I'll defer to you but is everything really so wrapped up?
sincerely

Hoyle was an honest scientist -- that's not the problem. The problem is that observations show his theory to be wrong. The discovery of the CMB in the 1964 essentially slammed the door on the steady state model. I'm not familiar enough with Arp to say much about him. However, it does happen sometimes that competent, honest scientists stubbornly stick to pet theories and rationalize away observational evidence that disagrees with them.

That said, current data overwhelming points to an (observable) universe with a finite age that is expanding from an earlier hot, dense phase. This is the big bang model.

Chronos

Arp attempted to hand wave away redshift as a distance indicators by cherry picking galaxies that appeared to be interacting, despite impossible discrepancies in their redshift. His examples of discordant redshift have been steadily eroded by better observations. His idea that quasars are ejected from mature galaxies has been relegated to the dust bin of failed theories.

*Gomar*

What is the universe expanding into? If I blow up a balloon, it will expand into the room and crash into the 4 walls, ceiling, and the floor. Thus, if the universe is a sphere, is it expanding into a sphere, or into some other geometric space/object that it will eventually crash into or hit?
Will this crash stop the expansion?

Or, is the universe creating space for itself to expand into where there was none before the BB?
If there was nothing before the BB, then where did the material or the matter of the BB come from? Some say, a previous universe collapsed into a size 1/10m cm. Others claim there are many universes; and ifcourse some say this is the 1st and only one ever.

bapowell

Quote by Gomar

What is the universe expanding into?

Nothing. Have a look at the FAQ -- I believe this issue is addressed.

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Chronos Recognitions: Gold Member Science Advisor	Arp attempted to hand wave away redshift as a distance indicators by cherry picking galaxies that appeared to be interacting, despite impossible discrepancies in their redshift. His examples of discordant redshift have been steadily eroded by better observations. His idea that quasars are ejected from mature galaxies has been relegated to the dust bin of failed theories.