Why do you believe in the Big Bang?

[Jon Miller]

(there are actually some promising leads)

JM

[Rogan Josh]

Originally posted by Jon Miller
well, I have not ran into one of his theories in my classes

I suppose it depends what he means by 'few'. I would probably rank him in the top 100 living particle physicists, but that doesn't include other branches of physics or anyone dead. His renown is purely because of his disability - if he didn't have his condition, no-one outside physics would have heard of him.

Have you heard of Sydney Coleman for example? Or Sheldon Glashow? Or Howard Georgi? Or Matinus Veltman? They have all had more impact imho, and I could go on and on....

I am sure he is cleverer than me though

[Kuciwalker]

Originally posted by Rogan Josh


Have you actually read any papers written by these 'eminent scientists'? Or are these theories translated to you via the popular media? So are you saying that you believe pro-Big-Bang scientists because they have the best PR? I too am an 'eminent scientist', but you never believe anything I say

The Big Bang is an extrapolation of known physics over 17 orders of magnitude. Doesn't that seem like a big leap to you?

Let's tackle just one problem with the big bang. The idea with the BB was that there was an initial explosion of energy and all matter was created out of that energy, right? Basically, there was a wash of photons (light) and a lot of the photons split into particle-anti-particle pairs, creating the matter we see around us today. But what happened to all the anti-matter? The theories all tell us that anti-matter must have been produced in equal amounts - so where did it go?

This is known as the Baryon-Asymmetry problem and is just one of the many many problems we have with the BB. But we never hear anything about it in the popular press.

Easy answer. It has been shown that certain antiparticles have a propensity to turn into normal particles. That, along with other things, is why the universe would not behave the same if every particle was switched to its anti-(or anti-anti-)particle.

[Rogan Josh]

Originally posted by GePap
Last I had read, matter and antimatter were NOT created in equal amounts, but instead matter was created in slightly large amounts, and what we see is the matter that was left after most matter and anti-matter annahilated themselves.

That's the idea, but it doesn't work. They need to have a theory which explicitly violates CP (which is essentially a time-revesal symmetry). The Standard Model does this (and this has been verified experimentally) but not nearly enough to explain the baryon asymmetry.

[Kuciwalker]

There is no temporal symmetry. There is ATP symmetry, though (antimatter temporal parity). If you ran the universe backwards, switched left and right, and turned every particle into its antiparticle, the universe would look exactly the same.

[Rogan Josh]

Originally posted by skywalker
There is no temporal symmetry. There is ATP symmetry, though (antimatter temporal parity). If you ran the universe backwards, switched left and right, and turned every particle into its antiparticle, the universe would look exactly the same.

That is the whole point. If you assume CTP (it is more usual to use 'C' for 'charge conjugation') then CP-violation is the same as T-violation. The Standard Model violates CP and thus T, but only a little bit.

[Kuciwalker]

It violates CP symettry because there IS not CP symmetry. Only CPT.

[Jon Miller]

there is CP symmetry

it is just broken in weak interactions

JM

[Jon Miller]

Rogan Josh

were you a particle phenomenologist?

JM

[Kuciwalker]

Thus, there ISN'T CP symmetry...

[Jon Miller]

if so could you help me with my HW?



JM

[Jon Miller]

Originally posted by skywalker
Thus, there ISN'T CP symmetry...

yes there is

it is just broken in some interactions

it is an excellent symmetry in strong interactions for example

JM

[Patroklos]

Science and Religion are not mutually exclusive.

Volkswagon built my car. I can study the end product as much as I want, indeed until I understand everything about every part and build the car myself. It doesn't change the fact that Volkswagon made the car. Science is the study of the works wrought by God. I don't believe in the "puff there it is" version of creationism. God is a little more creative than that

And while religion ultimatley requires faith, how is science any different? Religious minded people examine their form of "evidence," mainly metaphysical, and come to a point where they can accept a theory as true. Scientists collect as much evidence as possible, normaly physical, until they come to a point where they can accept a theory (note THEORY of gravity) as true.

And lets not kid ourselves, each side also shares a very similar trait: not everyone comes to the same conclusion. There are many different religions, and then sects within each religion. There are many different scientific theories out there, and many different divisions about the understanding of those theories.

Neither side has given up on inovation or modification of those theories. I know hundreds of poeple, who after examining the "evideance", switched from one religion to another. I also know many college chums who have changed their line on science from week to week. New religious groups form every day, new scientific theories are advanced every day, and the most extreme of the inovators in each field are treated in much the same way.

The only difference between religion and science is what each consider evidence, and since the evidence for each comes from idependant sources (pysical or non) they can exist happily next to each other. Unless of course you are hell bent on MAKING contridictions (ie hard corps creationists).

[DinoDoc]

Originally posted by Patroklos
Science and Religion are not mutually exclusive.

Indeed. It was a Catholic priest who's work the theory grows out of.

[Rogan Josh]

Originally posted by Jon Miller
Rogan Josh

were you a particle phenomenologist?

JM

I would like to think that I still am!

Yes, CP is exact in strong interactions. It is just violated in weak interactions. The interesting question is whether or not it will be violated by the Higgs boson's interactions. If it is, then maybe we can scrounge up enough CP violation to get round the baryon assymmetry problem.

To my mind, this will be one of the most interesting things to look for at the Large Hadron collider (although supersymmetry would be pretty exciting too )