How did the Big Bang explode?

[finaldeathh]

How did the big bang explode? Where did the gas come from? If there was 'nothing' before the big bang, then how can there be a big bang?

 

[doubletruncation]

I think it's best not to think of the big bang as an explosion. The term "big bang" is really a misnomer. I prefer to think of it, instead, as a time when the universe was substantially hotter and denser than it is today. <br /><br />The "big bang" is a theory that was put forth more than half a century ago to explain the fact that very distant objects like galaxies beyond the local group, seem to all be moving away from us at a rate that increases with their distance from us. This observation is what you would see if the universe were expanding (that is the volume of space is increasing - note on the local scale the forces of attraction between objects are strong enough that we don't experience this expansion on the Earth or within our own galaxy or even our own local group of galaxies). Now from general relativity we expect that the volume of the universe should be changing due the matter/energy that it contains. So, emboldened by other successful tests of the theory of general relativity, it's quite natural to interpret the observation that objects are moving away from us as an expansion of the universe. <br /><br />If the universe is expanding, then the volume of the universe should have been smaller in the past than it is today - in other words, the density of the universe should have been higher. This seems to be confirmed by looking at very distant galaxies (who's light that we see now was emitted further back in the past) which appear to be more active and undergoing more collisions (a hallmark of the density being higher) than galaxies in the local universe. Now if you extrapolate back into the past you'd expect the density to have been so high at some point that things like galaxies and stars would not be able to exist - everything would have been tightly packed together and the matter and light would be constantly colliding - things would have been much hotter. Any light that was emitted would not travel very far before it interacted with other matter - the <div class="Discussion_UserSignature"> </div>

 

[why06]

Incredible. 10/10. Textbook. Now that I think abou it I take back the first statement. Very Credible! <div class="Discussion_UserSignature"> <div>________________________________________ <br /></div><div><ul><li><font color="#008000"><em>your move...</em></font></li></ul></div> </div>

 

[why06]

Your very lucky you usually don't get answers like that on the first reply. The next best thing:<br /><br />http://en.wikipedia.org/wiki/Big_Bang <div class="Discussion_UserSignature"> <div>________________________________________ <br /></div><div><ul><li><font color="#008000"><em>your move...</em></font></li></ul></div> </div>

 

[lukman]

bravo, very comprehensive and brilliant, great think, great composition. <div class="Discussion_UserSignature"> </div>

 

[ianke]

Helo doubletruncation,<br /><br />I'd have to agree with the rest of them here, this was a very concise answer about the Big Bang. It was a pleasure to read. Thanks for your effort.<br /><br />Ianke <div class="Discussion_UserSignature"> </div>

 

[alkalin]

This is a good review of current notions but there is Cosmological mysticism.<br /><br />Some people think the universe began in a natural explainable way and so they propose the following:<br /> <br />In the beginning there was enormous heat coming from a point for some mystical reason. And there was not cause and effect for some mystical reason. And there was no conservation of energy for some mystical reason. And the early universe was opaque for some mystical reason. And early very intense heat and light from the BB has disappeared for some mystical reason. And the CMB (Cosmic Microwave Background) did not disappear for some mystical reason. And the universe in the beginning has large old galaxies for some mystical reason. And there is dark energy for some mystical reason. And there is dark matter for some mystical reason. And math logic has figured all this out for some mystical reason. <br /><br />And God saw that mystical reasons were good because it would punish man for walking the face of the earth thinking he knew all truth. <br />

 

[kyle_baron]

Wow, very profound, well done. <img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> <p><font size="4"><strong></strong></font></p> </div>

 

[SpeedFreek]

One of mankind's main failings, historically, is to assume that anything that cannot <i> yet </i> be explained must have some kind of <b> mystical </b> reason behind it. <img src="/images/icons/rolleyes.gif" /> <br /><br />Science is happy to say it doesn't know something yet. Only people who deal with faith and belief need <i> mystical </i> solutions. <div class="Discussion_UserSignature"> <p><font color="#ff0000">_______________________________________________<br /></font><font size="2"><em>SpeedFreek</em></font> </p> </div>

 

[R1]

doubletruncation, thanks for explaining<br /><br />I do have a question, what are these pockets of conversion called (or evaporation or something?)<br />I'm not sure I've heard of those or understand them, but I have<br />heard of matter vanishing of old age, but very, very old age.<br /> <div class="Discussion_UserSignature"> </div>

 

[doubletruncation]

<font color="yellow">I do have a question, what are these pockets of conversion called (or evaporation or something?) </font><br /><br />Hi John1R,<br /><br />I don't have much more than a casual understanding of inflation, so I probably wouldn't be able to do it justice. You may want to check out the wikipedia article and/or some of the references therein - http://en.wikipedia.org/wiki/Cosmic_inflation . As I understand it, the basic problem that inflation was invented to solve is the large-scale uniformity of the cosmic microwave background. After correcting for the motion of our galaxy through space, the cosmic microwave background is uniform to something like a part in 10000 (IIRC) over all directions in space. This is a bit of a mystery because if you look in opposite directions the regions of space that emitted the cosmic background radiation from those directions would never have been in causal contact - so how could their densities/temperatures have been equilibrated so nicely? Inflation is an idea that at some time prior to quark soup the universe underwent a very rapid exponential expansion and all of space that we can see now actually was in causal contact before it was ripped apart by this expansion. There are many different ideas as to what might have caused such a rapid expansion. In one idea the universe is in an energetic state - called a false vacuum - this causes the universe to expand exponentially. Every once in a while the vacuum tunnels to a lower energy at some location and you get a big bang there. I'm not sure if they have a technical name, I've heard them referred to as bubble universes before though. There are other versions where the switch to the lower energy state is not a sudden tunneling but a so-called slow roll. Aside from the uniformity of the CMB, if the universe did go through a period of inflation then there should be no detectable large-scale <div class="Discussion_UserSignature"> </div>

 

[doubletruncation]

Hi alkalin,<br /><br />I'm not sure whether or not you are speaking tongue in cheek, I apologize for taking you literally if you are. What do you mean by "for some mystical reason?" What exactly would constitute a "mystical reason", or does this mean we don't know and/or we may never be able to know? I would argue that everything following the big bang event itself does seem to follow in a deterministic fashion, there is no need to say the "intense heat and light from the BB has disappeared for some mystical reason," for example - this follows in a deterministic way from the initial conditions (you take an expanding universe with some initial contents and follow the laws of physics and find that it will be much less dense and much cooler later on). Nor is there reason to say that the CMB did not disappear for some mystical reason - again it follows from the initial conditions and the laws of physics. So why are the laws of physics as they are, I don't know, but I don't think it's helpful to suppose that the reason behind it is "mystical." I think it's better just to be honest and say we don't know.<br /><br /><font color="yellow">And God saw that mystical reasons were good because it would punish man for walking the face of the earth thinking he knew all truth.</font><br /><br />Suppose for a moment there is a God, and it made a universe that follows deterministic rules and it also made humans that would arise via those deterministic rules (or at least appear to have arisen via them) and have the curiosity to see the world around them and to figure out the rules and patterns in it. Why in the world would it then decide that those humans needed to be punished for figuring those rules out? That sounds to me more like a sadistic kid who beats up his own toys than like anything deserving of respect and admiration. But I suppose it's not right for me to presume to understand the Godly motives of God. Perhaps there is a God and perhaps that God is what I'd co <div class="Discussion_UserSignature"> </div>

 

[why06]

doubletruncation. As much as I love reading your post there exist a little button on your keyboard labled with the letters ENTER. Not to be mean, but a continous monalogue is ckinda hard to read. <div class="Discussion_UserSignature"> <div>________________________________________ <br /></div><div><ul><li><font color="#008000"><em>your move...</em></font></li></ul></div> </div>

 

[why06]

<font color="yellow">The Tree of Knowledge:<font color="white"><br /><br />Once we ate from the tree of knowledge the only thing to do was to kick us out of the Garden of Eden, because man could think. <br /><br />And with thought came knowledge. If man was not to be dismissed we would simply have escaped to find our on way on Earth if for no other reason than to find out why we had left that sanctuary that was God's. And realize, more so, that one day we may be able to make our own thoughts and judgements of God only find that our fruit was but one fruit from but one tree from the many gardens and orchards of God. And all our questioning and thinking were in vain. To turn out to be no more than a curse. <br /><br />And to think upon our final hour that we had removed ourselves out of the comfort of God only to realize that the knowledges we saught were within that Eden all along. And that this work, this toil, and this discomfort were all in vain. And but to find comfort in this single solitary fact that they had discovered with their technology and the philosophies what God had known in the Begginig. <br /><br />And in the beggining there was God. And in the End there was God. And God created man. And only to realize that even a Perfect Being could not create the Perfect Man. And God was without an equal and alone through the Forevers. And though it may not be said, man-kind, a being that sought its entire existance upon a flaw, was his greatest achievement.<br /> <br /><br />-why06-<br /><br /><br /><br /></font></font> <div class="Discussion_UserSignature"> <div>________________________________________ <br /></div><div><ul><li><font color="#008000"><em>your move...</em></font></li></ul></div> </div>

 

[doubletruncation]

<font color="yellow">but a continous monalogue is ckinda hard to read</font><br /><br />Point taken <img src="/images/icons/smile.gif" />. <div class="Discussion_UserSignature"> </div>

 

[why06]

Don't know how I got to that... hope I didn't end the discussion....Would someone like to continue... Any questions? <div class="Discussion_UserSignature"> <div>________________________________________ <br /></div><div><ul><li><font color="#008000"><em>your move...</em></font></li></ul></div> </div>

 

[space_coops]

doubletruncation, i enjoy your thinking.<br /><br />Good to see another Athiest on the boards.

 

[why06]

He never said he was an aetheist... I am a christian and might have said the same thing to prove a point. <img src="/images/icons/wink.gif" /> <div class="Discussion_UserSignature"> <div>________________________________________ <br /></div><div><ul><li><font color="#008000"><em>your move...</em></font></li></ul></div> </div>

 

[why06]

I support doubletruncations thinking as well, but not if or because he is aethiest. I just don't believe god would punish man like that. Not to mention that was a quite shallow view of God. There are mysteries and ther will always be mysteries. Its a fact of life. For everything we discover a thousand more questions arise. Someone rights the Theory of relativity. Why does deformed space-time cause gravity? Why can nothing exceed "c"? Some discovers a blackhole. How does information get out then? What happens inside. Does time reverse at its center? Would its center be a white hole? etc.<br /><br />Thats all. <div class="Discussion_UserSignature"> <div>________________________________________ <br /></div><div><ul><li><font color="#008000"><em>your move...</em></font></li></ul></div> </div>

 

[doubletruncation]

This post will have basically nothing to do with the big bang - please skip it if you're uninterested in talking about God/religion.<br /><br />I actually am a non-theist (atheist, or however you prefer to call it), but I do think this depends largely on what definition of "god" is used - I tend to prefer a very narrow one: basically a super-being intelligence(s) that is the origin of the universe and continues to influence it, but is not subject to its laws (in the sense that it is ultimately unpredictable to us). This can be either really nasty gods (like the one discussed earlier in the thread) or more reasonable and/or benevolent ones (it's certainly true that many religious people believe in Gods who I would very much like to exist). More general notions like a fundamental force that connects everything, or the ultimate answer to the deepest mysteries I'd prefer not to refer to as "god" unless it also has the previous attributes. <br /><br />I just don't see any reason, beyond what my own common sense/intuition suggests, to think that human intelligence is non-physical. The evidence continues to point to the neurocomputational picture of the brain where conciousness is an emergent phenomenon of a complex network of neurons. <br /><br />When some part of a person's brain is damaged there are often specific aspects of what would normally be considered a person's intelligence/conciousness/personality that are damaged/lost. If a person has a stroke, they may lose the ability to empathize with other people, or to feel strong emotions, or to communicate, or to think things through logically etc. If your consciousness was independent in some way of your physical brain what happened to those bits of it that are now lost when the brain was damaged? If your consciousness persists after death, in what form does it persist (do you regain those lost abilities/memories? what if you never had them to begin with?)?<br /><br />Of course there is still the subjective notion of self, a <div class="Discussion_UserSignature"> </div>

 

[why06]

LOL. This topic has got so far off from the Big Bang <img src="/images/icons/laugh.gif" /><br /><br />Anyway I like the way you think. Your very logcal, but you have to realize that you speak in a very "Iffy" manner, which I think you did on purpose. You see alot of people believe in life after death, but you don't have to to believe in God. In fact most Jews don't believe in an after-life, but they are some of the most religious people around. After life "persay" is a Platonic view. <br /><br />The upernatural is going on around us everyday. I have heard of people who change suddenly and without warning. Taken over by spirits they say? I have had first hand accounts of how a nurses will see people literally just burn up screeming in their sleep as their temperature goes of the charts. I have heard of people within my own family who have dreams e that predict the future. Where do dreams come from. There so many sightings of spirits and ghosts that fog gas could not nearly explain them all. There are so many mysteries in this world.<br /><br />Back to a lighter note. <br /><br />Yes me may be surprised, but that would be a tragically glorious day. There will always be somthing els to understand. One day we will think we know everything, but one new little thing will be discovered and everything will just start to break down, but who knows we may be surprised.<br /><br />Does anyone want to get back on subject eventually <img src="/images/icons/laugh.gif" /><br /><br /> I didn't know you were an atheist. My bad.<br /><br />Athiest is "a-thiest" kinda contradicts itself if you think of it like that. I know it doesn't really contradict itself I was just trying to lighten the mood. Did it work? <img src="/images/icons/tongue.gif" /> <div class="Discussion_UserSignature"> <div>________________________________________ <br /></div><div><ul><li><font color="#008000"><em>your move...</em></font></li></ul></div> </div>

 

[ianke]

I'm Smiling<br /> <div class="Discussion_UserSignature"> </div>

 

[ianke]

Hey I have been promoted! Asteroid always sounded a little like butt cream to me.<img src="/images/icons/laugh.gif" /> <div class="Discussion_UserSignature"> </div>

 

[why06]

But you still are an asteroid.... <img src="/images/icons/crazy.gif" /> <div class="Discussion_UserSignature"> <div>________________________________________ <br /></div><div><ul><li><font color="#008000"><em>your move...</em></font></li></ul></div> </div>