The Big Bang - Just a fun discussion

[berry120]

My two cents, but I do want to highlight the fact that you CANNOT create matter, nor destroy it....

HowStuffWorks "Problems with the Big Bang Theory"

Just an addition - pretty much all of the arguments in that link are addressed by my last point, that we haven't even got a vague clue what could have happened in the *very* early stages of the universe, approaching the Planck time. The alternatives it suggests are also all fundamentally flawed in many ways that make them much worse theories than the big bang. This is especially the case for the steady state theory, which was thrown out half a century ago when all the evidence started to point against it; and the big bounce theory, which relied on the assumption gravity would cause the universe's expansion to slow down and eventually recede. (As we all know, this was disproved in the 90's.)

Sure, the big bang theory isn't perfect, but it's a whole lot better than any other theory around, and it explains many, many more phenomena than it throws up questions for. Very, very few scientists working in this field reject it these days.

One point often overlooked is that the big bang theory doesn't really try to extrapolate before the Planck time either, it's the theory that, at one point in time (Planck time at the absolute earliest), the universe was in a very small space and was undergoing rapid expansion and cooling (and thus its various stages start from there.) In short, it doesn't start from 0, it starts from, at the absolute earliest, 10E-44 onwards. Because of this it therefore, contrary to common belief, *doesn't* necessarily violate any of our physical laws at all - it certainly doesn't state that matter just popped into existence out of nowhere. It was all there, just in an unbelievably dense state (and thus the first law of thermodynamics is upheld.)

 

[Stormaggedon5555]

Nope. Anti-matter, in all probability, behaves pretty identically to normal matter in terms of its fundamental particles - the issue is that this has never been experimentally observed. Public opinion seems to think of it almost as some kind of mysterious voodoo, whereas all it actually is (in hydrogen's case) an antiproton and a positron - just a different makeup of fundamental particles we already know about. Anti-hydrogen was first created about 20 years ago now, but it's so unstable that actually keeping enough of it around for long enough to conclusively measure it is the real challenge. IIRC I did see a paper not long ago where they'd made improvements in this regard - so perhaps that development means it's not too far off experimental validation (or refutation.)

The other thing to bear in mind is that the big bang is really a *terrible* name for this event, which wasn't really big (it was everywhere) and it wasn't a bang in the slightest (an expansion would be much more accurate.) This is where a lot of the misconceptions and difficulties have stemmed from - people hear "big bang" and immediately think of some kind of explosion in existing space. It wasn't, it's instead the notion that if we take our current best models of the universe and use them to rewind it by billions of years, we end up in the state where all of space was in the same place at once.

As for the speed increasing, no-one really knows why - the best theories come from the realms of dark energy and negative pressures, but that's a whole new board game so I'm deliberately going to stay away from that area!

The real limitation of the "big bang" (everywhere expansion) is that we can only rewind to a certain point before our current physical models completely and utterly break down, namely the Planck time. (Actually, we probably shouldn't push our current models to within many orders of magnitude of this time constant, but we can at least obtain a limited guess by doing so.) Beyond the Planck time constant however, no-one can claim to have any reasonable idea that's anything beyond guesswork - all our current theories are based on that atomic unit of time (and the corresponding Planck length), so here lies the real mystery. Before that time, or even close to it, all bets are off.

The only thing I am willing to bet is that there's likely a whole new field of physics that may well crop up the closer we get to measuring close to the Planck time - and I for one find that incredibly exciting.

Very well put I completely agree.

 

[root]

My two cents, but I do want to highlight the fact that you CANNOT create matter, nor destroy it....

HowStuffWorks "Problems with the Big Bang Theory"

except you can both create an destroy matter...

The sun is steadily burning up all it's matter and releasing energy.
you can create matter from energy.

there is even a pretty famous equation that links the two (E=MC^2)

(that's the problem with only quoting half a source!)

 

[iPwn]

Nope. Anti-matter, in all probability, behaves pretty identically to normal matter in terms of its fundamental particles - the issue is that this has never been experimentally observed. Public opinion seems to think of it almost as some kind of mysterious voodoo, whereas all it actually is (in hydrogen's case) an antiproton and a positron - just a different makeup of fundamental particles we already know about.

Fair enough. Is the consensus still that anti-matter and matter react violently when they meet? Not trying to use this to disprove anything, but if bound by the same laws, then it should hypothetically exist in the same makeup of everything we see... meaning that there should be some pretty radical reactions happening in the visible universe, right?

Now, it is entirely possible that these do happen, even on a daily basis, but in a galaxy or solar neighborhood so wildly far away that we can't observe them. However, with the absence of any "We witnessed another collision today" type of headlines, that lends merit to the belief that anti-matter really did 'lose' the battle in the early stages of the 'everywhere expansion'.

Again, I'm no physicist by any stretch of the imagination, just trying to take a logical approach to what I'm hearing.

I remember watching a show by the Hawk where he had stated that the universe, if 'summed' as in a math problem, would equate to zero. He went on to argue that for every piece of matter, there is a corresponding anti-matter particle. For every positive, there is a negative. Now, in my mind that holds merit simply because we know there is always balance (e.g. As above, so below; Newtons 3rd law). How though, does that sit with a belief that matter and anti-matter cause atomic level explosions when they meet?

Rather, just as in math, when you have a positive 3 above a negative 3, they simply cancel out and equate to 0. Would the same not hold true in the physical universe?

 

[berry120]

Fair enough. Is the consensus still that anti-matter and matter react violently when they meet? Not trying to use this to disprove anything, but if bound by the same laws, then it should hypothetically exist in the same makeup of everything we see... meaning that there should be some pretty radical reactions happening in the visible universe, right?

"React violently" is a bit of a misleading term to use - but yes, they annihilate each other when they meet, correct. This has long been shown, and is why it's so difficult to keep the stuff around long enough to observe - as soon as an atom of anti-hydrogen meets another atom of matter, the two annihilate and produce a small amount of energy.

It's incredibly unlikely that there's still any significant amount of antimatter around in our observable universe for this reason, none has ever been observed and given the huge amounts of matter we know about, any around *now* would almost certainly be overwhelmed and destroyed by collision with matter.

I remember watching a show by the Hawk where he had stated that the universe, it 'summed' as in a math problem, would equate to zero. He went on to argue that for every piece of matter, there is a corresponding anti-matter particle. For every positive, there is a negative. Now, in my mind that holds merit simply because we know there is always balance (e.g. As above, so below; Newtons 3rd law). How though, does that sit with a belief that matter and anti-matter cause atomic level explosions when they meet?

First off, you need to get out of the mindset of Newtonian physics when talking on this level While some concepts can still apply, in reality the laws of physics on this quantum level can seem rather different than the norm.

I believe what you're getting at is the theory that at the time of the big bang, our best models predict there were equal amounts of matter and antimatter, which leads us to a seeming paradox in that why didn't the two annihilate each other and cause 0 mass to be left over?

This is where, in reality, we *want* to find that there's a certain asymmetry between matter and antimatter which would explain this, but as of yet we're not entirely sure what it is. It certainly doesn't negate the big bang theory, though if it were conclusively proved that there's no asymmetry, it may well shake it up a bit. (Bear in mind that antimatter observations are still very much in their infancy - this is a rather new area.)

I believe the good people at CERN got us a bit closer to finding the answer last year when they found that antimatter actually decays at a slightly faster rate than matter. This may or may not equate for the total "victory" of matter over antimatter, but it certainly gets us closer to finding any asymmetry between the two.

 

[iPwn]

"React violently" is a bit of a misleading term to use - but yes, they annihilate each other when they meet, correct. This has long been shown, and is why it's so difficult to keep the stuff around long enough to observe - as soon as an atom of anti-hydrogen meets another atom of matter, the two annihilate and produce a small amount of energy.

Interesting. I was of the understanding that when matter hit anti-matter, Hiroshima level events took place. So then the theory of relativity doesn't 'exactly' apply as some of the energy is being "cancelled"? Or am I still off base there?

First off, you need to get out of the mindset of Newtonian physics when talking on this level While some concepts can still apply, in reality the laws of physics on this quantum level can seem rather different than the norm.

That's fair, I was simply referring to the fundamental balance (hence only referencing the third law), but I see what you're saying there.

I believe what you're getting at is the theory that at the time of the big bang, our best models predict there were equal amounts of matter and antimatter, which leads us to a seeming paradox in that why didn't the two annihilate each other and cause 0 mass to be left over?

Yea that concept is still a little hard to follow... I get that if you had an explosion, you sometimes have residue of the explosive material left over... still in a combustible state, it was simply propelled faster than the consuming fire and thus escape reaction. Now, that kind of analogy would lend to the below:

I believe the good people at CERN got us a bit closer to finding the answer last year when they found that antimatter actually decays at a slightly faster rate than matter..

So let's say that most, if not all, of the anti-matter has completely decayed. Would that mean that the visible universe is soon to follow?

What then of the observation of matter simply assembling 'on it's own'? (e.g. Energy concentrations meet and form matter). Could the same be true of anti-matter?

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What I find most fascinating about all of this is that; no matter how sophisticated we as a species seem to get, it appears that some of the most basic concepts and theories start falling apart the closer we look. We have 'laws' that apply to everything we see, then we take a closer look and POW! It doesn't work like anything we had though before. So we make new laws and theories which test true. Take a closer look? Well then we erase the chalkboard once again.
I can't imagine living in a world where everything is known. What a boring place!

 

[berry120]

Interesting. I was of the understanding that when matter hit anti-matter, Hiroshima level events took place. So then the theory of relativity doesn't 'exactly' apply as some of the energy is being "cancelled"? Or am I still off base there?

Sorry, ambiguous wording on my part. I say a small amount of energy because when an atom of one hits an atom of another, the amount of energy released is indeed ridiculously small. Considering that we've only managed to ever create ~30 atoms of anti-hydrogen at once, this amount is still absolutely negligible.

Of course, if you're talking about kilos at a time then the amount of energy produced would indeed be astronomical - but we're at the very least many decades off anything on that scale.

So let's say that most, if not all, of the anti-matter has completely decayed. Would that mean that the visible universe is soon to follow?

Nope, we're talking about decay that was occurring before, or as the destruction of antimatter and matter was taking place, not a gradual decay that's occurred since. I actually take part of my last reply back, after looking at the relevant research in a bit more detail, this particular asymmetry is nowhere near enough to explain the entire prevalence of matter over antimatter. It is however a step in the right direction, and shows that this particular field probably has many more secrets to give up yet!

What then of the observation of matter simply assembling 'on it's own'? (e.g. Energy concentrations meet and form matter). Could the same be true of anti-matter?

No idea - I don't think this has been experimentally tested. However, such anti-matter did form in a matter-filled universe, then it'd almost certainly be immediately converted back into energy again (owing to any collision with matter.)

 

[iPwn]

No idea - I don't think this has been experimentally tested. However, such anti-matter did form in a matter-filled universe, then it'd almost certainly be immediately converted back into energy again (owing to any collision with matter.)

Quantum Fluctuation

That spawns an entirely new debate though... It seems that most mainstream scientist reject the idea of quantum physics because it rocks the very foundation of what 'we know.' That being the physical universe itself.

Anywho, back on topic.

I think you said it best above.

we haven't even got a vague clue what could have happened in the *very* early stages of the universe

I think it's fascinating to ponder these types of questions, but with the realization that there's (currently) no way to truly prove exactly how it all went down... err everywhere.

 

[Life]

I just read this: The big bang Theory: God spoke and BANG! it happened.

THE BIG BANG THEORY IS TRUE!

 

[evan.briggs]

I just read this: The big bang Theory: God spoke and BANG! it happened.

THE BIG BANG THEORY IS TRUE!

Let's just say you're awesome!!

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