Teach me about the big bang theory.

Lord Kenneth

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I am uneducated in this field.

Also, A question I have:

Creationists maintain that something had to createor cause matter/start creation/etc. Ignore the fact that their own beliefs are hypocrisy... but, is that false?
 
Warning: what follows are the rantings of an armchair scientist.

You could probably find most of what you need by doing searches on the internet, though you might have to learn to filter the crap.

Here is the short "history" of the big bang. Others on here will be more accurate than myself.

1 ) Einstein general theory - doesn't predict a stable sized universe. The laws of physics demand that it either be contracting or expanding. To combat this Einstein initially theorized a "dark force" which caused some repulsion and resulted in a constant sized universe.

2) An astronomer (Hubble?) did some measurements that showed that the universe was expanding. Einstein's dark force was scrapped.

3) Scientists began to try to trace the universe back in time. From the current state of the universe and scientific theory they tried to calculate the state of the early universe. Far enough back you find that the universe was incredibly small space. Before that it would have been a point. To be accurate, the laws of physics as we know them breakdown before you can trace it all the way to being a point.



My knowledge of the evolution of the universe.

First we have the big bang. What caused it? We don't know. What pred-dated it? Probably nothing. No space, no time, nothing.

Very shortly we find the universe to be a dense quark soup. It is to hot for quarks to exist as stable protons neutron etc. Last I heard, our physics models are unreliable prior to the quark soup.

As the universe expands and cools, quarks are able to form stable bonds and become neutrons and protons and other junk, and eventually these can come to togethor and form atoms. Somewhere in here the universe becomes more or less transparent. Photons can travel with out being absorbed immediately, and it is this state of the universe which we the cosmic background radiation from.

Cooling and expanding continue, allowing more things to organize more into what we see today. When stars first form they become the breeding ground for heavier elements through fusion. Really heavy elements may be the results of collisions of heavy stars and such. But it are these events that start to fill out the periodic table. Super nova and these other catastrophic events are what spread these heavy elements until you get the state of things around our time and place that enable earth like planets.

I don't know if I explained well, I'm not sure if I explained it accurately, but that might be a good starting point. Hopefully people will speak up if I am talking nonsense.
 
The Big Bang Theory involves the universe expanding. There is the hot big bang model and the inflationary model. In Stephen Hawking's book, "A Brief History of Time", it says on page 162, "In the hot big bang model the rate of expansion is always decreasing with time, but in the inflationary model the rate of expansion increases rapidly in the early stages." I was told by my younger brother that it was found out recently that the universe is expanding at an ever quickening pace. This would fit in more with the inflationary model than with the hot big bang model.
 
Dark Cobra said:
I am uneducated in this field.

Also, A question I have:

Creationists maintain that something had to createor cause matter/start creation/etc. Ignore the fact that their own beliefs are hypocrisy... but, is that false?
Awright, lemme' have a shot at it. :)

The universe, that is all the "stuff" we can see and touch, all the energy, all the "space" (that is, the actual dimensions themselves) and some other things (called "dark matter" and "dark energy" because we can't directly sense them) all originated from a single point, what is called a singularity. A single "dot" like the points we learned about in high school geometry, with EVERYTHING all scrunched up inside it.

No, we don't know where it came from, but some theories are that it may have been from a kind of extra-dimensional "hyperspace" that exists outside of our universe, like our universe is an expanding bubble inside some sort of cosmic glass of beer. That's my favorite way to look at it, we're all part of a bubble floating in beer, heading for the foam. I just hope it's a GOOD beer!

Anyway, as soon as that dot/point formed, the "universe" began to exist. Time started (no, it didn't exist "before" this, time is just another dimension, like the space ones, try not to think of some sort of time running in the background -- this isn't like a movie). OK, so we have the hot dot and then, according to the best theories, we entered an "inflationary" phase. This means that the dot swelled up VERY fast, faster than light speed (if light had existed then, but things were still to hot and dense for light). In an extremely small fraction of a second the universe went from this point to very, very, big. I don't know how big, but BIG, like light years in size (I think), but it took 10e-25 seconds to get there. That's a decimal with twenty-five zeros after it, then a one. A very small moment in time.

Then things slowed down and we get to the "regular" expansion which we are still in. The inflated ball grew larger and cooler (remember though, there is nothing "outside" this "ball," it really is the only thing around (except maybe the surrounding beer, but nothing IN the ball can get TO the beer, too bad for all of us). As far as the ball is concerned it could "sense" that it may be getting larger but it can't tell anything about the "outside" world.

After expanding this way for awhile, different "stuff" condenses out of the soup as it cools. At ~380,000 years of age atoms and light can form, and suddenly the entire ball is full of gamma radiation, light and heat. It is VERY hot (I don't know how hot, I don't have the book handy, but you get the idea).

It keeps expanding and cooling, and stars, galaxies, quasars and other things we know and see form from gravity. The original inflationary time set up the "structure" and distribution of the stuff that would form atoms to make this possible. As it continued to expand and cool the original gamma radiation got "stretched" from red shift and became the cosmic background radiation we now detect. In fact, the original ball has cooled generally to less than three degrees above absolute zero, with the exception of the hot spots in and near stars, planets, and the other members of the cosmic zoo. But overall the universe has become pretty cold.

That "dark matter" and "dark energy" are invisible to us but seem to be real. The dark matter is detected by its gravitational pull and seems to make up a lot of what holds galaxies together. Calculations show that most of them would've flew apart if this dark matter hadn't been there all along (and seems to still be there) to increase their gravitational pull. That, and all the visible regular matter, have also been slowing the outward motion of the matter in the universe, and was once thought to POSSIBLY be enough to cause it to eventually stop flying apart and drag it back in to an eventual "big crunch," the opposite of a big bang.

That won't happen, though, because of that "dark energy." This is a force that seems to cause everything to REPEL everything else, in direct opposition to gravity. It seems to be undetectable at relatively close distances (like between nearby galaxies), but becomes more significant as distances increase. It is only relatively recently (like the last few billion years) that a good deal of the universe has become far enough from some of the other parts that it has become significant.

The net result of that dark energy is that the expansion will continue, but also accelerate with time. We'll never have a big crunch, so we may end with a whimper, not a bang, after all.

Sorry this ran long, but you did ask about the origin of the universe! :D
 
Re: Re: Teach me about the big bang theory.

garys_2k said:

A single "dot" like the points we learned about in high school geometry, with EVERYTHING all scrunched up inside it.

No, we don't know where it came from, but some theories are that it may have been from a kind of extra-dimensional "hyperspace" that exists outside of our universe, like our universe is an expanding bubble inside some sort of cosmic glass of beer. That's my favorite way to look at it, we're all part of a bubble floating in beer, heading for the foam. I just hope it's a GOOD beer!

Thanks for the input about what happened before the Big Bang. About a year ago I had a huge argument with a person who claimed that the Big Bang was the beginning of time and existence. I argued that it was not the beginning of time because if there was a Big Bang, there was motion, and without time there is no motion. So in order for time to move there would have to be motion to measure it by. Time is motion and motion is time. So there had to be time or motion in order for the Big Bang to occur because the Big Bang requires previous motion to trigger it. From there I argued that there was no beginning to time. This person I was arguing with just really wasn't getting it.
 
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The Big Bang Theory involves the universe expanding.
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Yeah, it expanded out of nothing!

Tell that one again, plleeeeaaassseee gramps! Pleeeeaaaassseeee!

I like that story.
 
Which story did you prefer? The one with the big magical being in the sky?
 
Well the Earth is actually a flat disc the rests on the backs of four elephants standing on agiant tortoise. Now while the sex of the tortoise for earth is unknown the fact remains that it must be either male or female.

This has lead scientists to conjecture that other worlds must also be floating on the backs of other tortoises, either male or female. These tortoises swim through the ocean of space towards a final destination where they will all indulgen in an orgiastic mating that has been referred to as the BIG BANG!

---apologies to Terry Pratchett
 
The question is, of course, what happened to the fifth elephant...
 
rwald said:
Which story did you prefer? The one with the big magical being in the sky?


No, I prefer the big nothing that existed in space that suddenly exploded. Yes, the one where nothing existed and exploded.

That is so much better than saying a god did it.
 
At least we're only claiming one impossible thing...

Wait, if God created the universe, than what created God? Oh, God's allowed to be immortal. But the universe isn't? Is that the sound of shifting goalposts I hear?
 
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Wait, if God created the universe, than what created God?
----


Maybe the "Big Nothing That Existed Then Exploded".


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Is that the sound of shifting goalposts I hear?
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No, that was the sound of me undoing a severe 'frontal wedgie' I created from sitting down too long.
 
Something that people aren't mentioning is that to really understand the theory you have to learn some advanced math.
It is not as simple as talking about nothing coming into somethingness. Very counter inuitive, but many things in science are. But the neat thing is that once you do understand, you are often able to do useful things and make accurate predictions.

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WR to the posts that have been made so far:
Note that when people talk about the universe starting from a "point" it is not true. Singularities aren't physically "real", the are what happen when our theory is not accurate enough to predict the outcome.

I believe Michio Kaku talks about the lack of need for "first cause" in Hyperspace. Something to do with gauge theory which I don't understand.
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Even non-cosmologists like you and me, can appreciate that the theory has many subtle predictions, some of which have been confirmed.

You can verify that things like the 3 deg background radiation were being predicted before they were discovered. Other predictions include the energies required detect certain kinds of particles in accelerators. Astronomical measurements of the galaxies, their speeds of recession and spatial distrubution also let us know if our theory about how the universe started is consistent with what we can observe.

The short story is that we don't know exactly how the universe started, but out picture keeps getting clearer as more experiments are done. I believe that the big bang theory (which of course, encompasses many different specific plausible/consitent histories) is largely accepted and there are have been no observed data that strongly suggest an alternate origin. Remember that the timescales involved during the initial bang are phenomenally fast (10 to the -ve 10's of exponents), and the farther we go back, the less confident we are that our model accurately predicts the true picture.

Remember just becuase most people don't understand something completely, doesn't mean it isn't true; some things take a long time to understand. It is important to remember that scientists have used the model of the big bang to make important (and difficult) predictions; which is why we have confidence in the model.

That's not to say that there is a lot we don't know about the universe (i.e. why the surface of the sun is so damn hot)...even though we have things we can't explain, none of them suggest that the universe started in a different way.

P.S.
Have you tried ordering that pizza yet DC?
 
Whodini:
No, I prefer the big nothing that existed in space that suddenly exploded. Yes, the one where nothing existed and exploded.

That is so much better than saying a god did it.
Indeed it is. Guth, the father of inflationary theory, explains:

The Universe is the ultimate free lunch

An excerpt:
This borrowing of energy from the gravitational field gives the inflationary paradigm an entirely different perspective from the classical Big Bang theory, in which all the particles in the Universe (or at least their precursors) were assumed to be in place from the start. Inflation provides a mechanism by which the entire Universe can develop from just a few ounces of primordial matter. Inflation is radically at odds with the old dictum of Democritus and Lucretius, "Nothing can be created from nothing" If inflation is right, everything can be created from nothing, or at least from very little. If inflation is right, the Universe can properly be called the ultimate free lunch.
 
garys_2k,
A little careless, I think:
but it took 10e-25 seconds to get there. That's a decimal with twenty-five zeros after it, then a one.
10^-1 = .1
10^-2 = .01
10^-3 = .001
.....
.....

And some calculators (the one with win98) would have
10e-25=10*10^-25=1*10^-24=1e-24
so decimal point, 23 zeros, 1
 
Well, when one considers that 2800 years ago, it was believed the earth was on a tortoises back. . .

and 2200 years ago it was believed it was carried by a cursed man named Atlas. . .

and 1200 years ago it was believed to have been created by the hand of God. . .

and today it is believed to have been created by the Big Bang. . .

I think it stands to reason that in 1000 years:

1. There will be a different, newer, 'better' theory out there.

and

2. They will mock, redicule and laugh at all of the 'stupid ancients' who believed in that Big Bang hoo doo.


Look, as time and 'True' science change every hour, I get mroe and more skeptical of EVERYTHING science tells us is true. What, we are supposed to just believe for all eternity when they tell us something new and profound that, indeed, "THIS time, we are SURE we're right!"?

Come on!


Argue all you want, the Greeks were SURE the Earth was carried on the back of a giant tortoise. No question. Absolutely as positive, if not MORE positive then we are today of the Big Bang.


Oh, and hi all. My first post.
 
Welcome to the forum Larspeart.

Okay, starting with a pedantic point, it wasn't the Greeks that believed that the universe was on the back of a turtle.

The difference between beliefs and science is that science, by testing its assumptions, gets successively closer to how the world works. Science offers provisional truth, always subject to revision or negation. However, with science, this is based on new evidence, not changing beliefs. I'm sure many on this board will respond much more elegantly on this point than I will, so I will let them.

My question for you is: you just typed your answer on a computer, which uses a lot of engineering developed by science, all of which any competent scientist would describe as true (not True). Do you think in 1000 years that science will be laughing at us, calling them not true at all? Remember, computers really do work.

There is a huge change in methadology in the last 300 years or so of your timeline. The scientific method allows us to accumulate knowledge, not just change our beliefs. In 1000 years the science of our computers, for example, will still be correct (for example, how n-p-n junction transisters work). New science will be based on this knowedge, and of course the computers of that time will work in a different manner, but that makes today's semiconductor technology obsolete, not wrong.


So I don't see why in 1000 years scientists will be laughing at today's scientists. Current models on the beginning of the universe are based on incomplete data, and it is certainly possible that as more data comes available that theories may change. For example, Newton was quite wrong about the behavior of objects at relativistic speeds, but no one laughs at him or mocks him, for his work was based on scientific principles, and it remains correct at the non-relativistic speeds in which he performed his experiments.

Roger
 
Larspeart:
Well, when one considers that 2800 years ago, it was believed the earth was on a tortoises back. . .

and 2200 years ago it was believed it was carried by a cursed man named Atlas. . .

and 1200 years ago it was believed to have been created by the hand of God. . .

and today it is believed to have been created by the Big Bang. . .

I think it stands to reason that in 1000 years:

1. There will be a different, newer, 'better' theory out there.

and

2. They will mock, redicule and laugh at all of the 'stupid ancients' who believed in that Big Bang hoo doo.
I certainly hope that there will be a better theory. It would be a sad state of affairs if there was suddenly nothing new to discover.

However, I doubt any educated person would laugh at the current theories. No one laughs at the achievements of the ancient Greeks. Au contraire.
Look, as time and 'True' science change every hour, I get mroe and more skeptical of EVERYTHING science tells us is true.
Skepticism is important. However, when a theory is backed by evidence, peer-reviewed, etc, etc, its safe to assume that it describes reality fairly well.
What, we are supposed to just believe for all eternity when they tell us something new and profound that, indeed, "THIS time, we are SURE we're right!"?

Come on!
No scientist has this opinion. Science is an iterative process. No one laughs at Newton's gravitational theory, despite the fact that Einstein came along with a theory which explained more than Newton's. Heck, you can still send a rocket into space and a probe to Jupiter using just Newton's theory.
Argue all you want, the Greeks were SURE the Earth was carried on the back of a giant tortoise. No question. Absolutely as positive, if not MORE positive then we are today of the Big Bang.
Really? Odd, given that the circumference of the Earth was measured by the Greeks.
Oh, and hi all. My first post.
Hi, and welcome aboard.
 
Okay, excellent point. Now for my counterpoint.

Einstien had a number of very good views and points, most of which were/are true to this day in our thinking. However, there have (in just 50-80 years) been numerous ones that were widely held to be true, and are just now proving to be untrue. Take the speed of light, and the fact that, as he puts it, nothing can go faster. Twas a huge blow to time-travel buffs, but everyone looked at his theories and said 'yup, by Jove, the chap is right'. WRONG. We now have witnessed both in nature and in labs, faster then light travel, at the atomic and the subatomic level.

So, in not 300, but rather 50 years, what was once held as hard fact, is now somewhere between mostly true and incorrect.

Want more? The age of the universe. First, it was 8000 or so years old. Then, it was 1 billion years old, then 12. then 14. Just recently, I read that now, we think it is 14.4-16 billion years old, and another university believes it is at least 20 billion. So, you're going to tell me that in 1,000 years, they will still think it is 14.4 billion years old? Yet, hundreds upon hundreds of very respected scientists and math guys point to gobs upon gobs of 'hard evidence.

Humans believe that they can figure out the really good questions in life if they devote enoguh thought and math to the problem. The fact is, our brains are prone to several things, one being fallability. The other is ego. We believe that humans can figure out anything due to our greatness, and neglect that we are more often wrong in life then right.

I'm sorry, but just because we invented a computer for me to type on doesn't mean i believe that in 10,000 of true society, we have everything figured out yet.
 

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