38 replies to this topic

[Darkwind]

Could the Universe be expanding because the so called big bang never stopped and some where in the Universe there is a point were material from "the bang" is still spewing into a hot section of the Universe?

[sumthingnice60]

The big bang was an explosion at a certain point in time and is used to describe the creation of time and space rather than to describe the expansion of space. So, I don't believe the big bang is still going on. I like to think of this like an atomic bomb. The instant the bomb hits the ground can be thought of as the big bang. The radiation that expands after the bomb hits doesn't mean that the bombing is still happening.

[Darkwind]

sumthingnice60 on Dec 11 2007, 02:14 AM, said:

The big bang was an explosion at a certain point in time and is used to describe the creation of time and space rather than to describe the expansion of space. So, I don't believe the big bang is still going on. I like to think of this like an atomic bomb. The instant the bomb hits the ground can be thought of as the big bang. The radiation that expands after the bomb hits doesn't mean that the bombing is still happening.

Say it is not a Bang so much as an opening in another dimension spewing time and space in to this universe.  

[sumthingnice60]

Darkwind on Dec 10 2007, 08:04 PM, said:

Say it is not a Bang so much as an opening in another dimension spewing time and space in to this universe.

If I'm not mistaken, then the reason the universe is expanding is because of the force of the big bang. The big bang cause space to continue outward which is why it's moving outwards today. But it is also slowing down because of gravity.

[Torgo]

Okay, there are a lot of misconceptions floating around here.  They are some of the most common misconceptions people have of the big bang.  

The big bang was not an explosion of a very dense kernel of matter into a bigger empty space.  What it is is the idea that the universe was much denser in the past and it is expanding.  When we look out across space, we see that everything is moving away from everything else on large scales.  There is no "center" to this expansion - it is uniform everywhere.  If there was some original object that exploded then things near the center would be moving slower in order to have been found there in the first place.

What we see is that in the past space was smaller and space is expanding.  Perhaps a better way to put this is that the distance between two points always increases with time.  On very small scales, up to the size of galaxy clusters, gravity overcomes this and things do not move apart.  On larger scales where gravity is weaker, this forces objects apart faster than gravity can pull them together again.  

For all we know the universe could be infinite, and have always been infinite from the beginning of its existence.  But space may have stretched such that it is, I suppose one could say, a "much bigger infinite" than it was at its beginning.  I lack the mathematical terminology to say anything clearer than that, I'm sorry.

Interestingly enough, looking at the redshifts and intensities of supernovas in distant galaxies that are known to always have the same intensity and spectrum, it has come to light that the universe's expansion is actually ACCELERATING.  No one KNOWS why this is, but this is the observation that "dark energy" has been proposed to explain.

[rideron]

If all matter in existance originated with the "Big Bang"  what is it that the Universe is expanding into????  What is, and from whence came, the 'space' into which the Universe is now expanding if not from the Big Bang itself? Was it already there before the Big Bang happened? ?  And if you could get out to the very outer limit of the edge of the expanding Universe, and take one step beyond that, where would you be?

Edited by rideron, 12 December 2007 - 10:00 PM.

[sumthingnice60]

Torgo on Dec 11 2007, 10:49 PM, said:

Interestingly enough, looking at the redshifts and intensities of supernovas in distant galaxies that are known to always have the same intensity and spectrum, it has come to light that the universe's expansion is actually ACCELERATING.  No one KNOWS why this is, but this is the observation that "dark energy" has been proposed to explain.

Wow, it's accelerating? I totally didn't know that. I always assumed that the expansion process is slowing down.

[Torgo]

rideron on Dec 12 2007, 04:59 PM, said:

If all matter in existance originated with the "Big Bang"  what is it that the Universe is expanding into????  What is, and from whence came, the 'space' into which the Universe is now expanding if not from the Big Bang itself? Was it already there before the Big Bang happened? ?  And if you could get out to the very outer limit of the edge of the expanding Universe, and take one step beyond that, where would you be?

The big bang is NOT a bunch of mass originating at one point and spweing out into space.  As near as we can tell matter and space originated together with matter embedded in space throughout.  Since that time the space has stretched moving the matter further and further apart decreasing the overall density of the universe and stretching light out to longer and longer wavelengths - hence the Doppler shift.  

The classic example to ilustrate this is a balloon.  Take a sharpie and put little dots all over it.  These are collections of matter, like galaxies.  Blow up the balloon, or take your hands and stretch it out - the dots do not explode out from any point, they just get further and further away while the rubber they're on gets bigger.

As near as we can see the universe has no edge.  We can only see a finite distance away but that is because light has had a finite time to travel since the universe became transparent to light when it cooled down enough for the initial plasma to combine into neutral gas molecules.

Quote

he instant the bomb hits the ground can be thought of as the big bang. The radiation that expands after the bomb hits doesn't mean that the bombing is still happening.

The background radiation we see is NOT the radiation from the (nonexistant) "Explosion" of the big bang.  What it IS is the heat glow of the universe at the moment it became transparent to light, redshifted down into the microwaves by the expansion of space.

Edited by Torgo, 13 December 2007 - 02:28 AM.

[joc]

The Big Bang is a myth.  It never happened.  It is an err in thought process to think that it did.   The Universe is not expanding.  This is also a myth.   They are both theories...and not very good ones either.

Edited by joc, 13 December 2007 - 02:33 AM.

[magnetar]

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Edited by magnetar, 13 December 2007 - 08:47 AM.

[sumthingnice60]

joc on Dec 12 2007, 06:32 PM, said:

The Big Bang is a myth.  It never happened.  It is an err in thought process to think that it did.   The Universe is not expanding.  This is also a myth.   They are both theories...and not very good ones either.

The big bang theory is the best theory we have right now. If you don't think they are good, then what is a good theory?

[The Silver Thong]

sumthingnice60 on Dec 12 2007, 08:51 PM, said:

The big bang theory is the best theory we have right now. If you don't think they are good, then what is a good theory?

The big bang is a theory yes, and it does hold the scientific community together. What Joc is saying (if I may be so bold) is that God created the universe and the reason why is still unknown. Science has many answers or theories based on mathematical equations that some see as a way of dismissing god.  The answer to some, is what is your faith or what can science "prove" or show as proof.  Many hold onto faith and thats fine, until it contradicts what can be proven. Hence we see this.

Quote
"The Big Bang is a myth. It never happened. It is an err in thought process to think that it did. The Universe is not expanding. This is also a myth. They are both theories...and not very good ones either."Unquote.

Hmmm " the Universe is NOT expanding"  why does he say this? Because he believes in God, as the maker of everything. God makes no mistakes, hence what is know has been forever. The Universe is expanding and we can see this as fact. I will not throw out a claim that something is not so because I say so, as some do. Faith is just that faith, but science works a wee bit different.

[joc]

The Silver Thong on Dec 13 2007, 04:30 AM, said:

The big bang is a theory yes, and it does hold the scientific community together. What Joc is saying (if I may be so bold) is that God created the universe and the reason why is still unknown. Science has many answers or theories based on mathematical equations that some see as a way of dismissing god.  The answer to some, is what is your faith or what can science "prove" or show as proof.  Many hold onto faith and thats fine, until it contradicts what can be proven. Hence we see this.

Quote
"The Big Bang is a myth. It never happened. It is an err in thought process to think that it did. The Universe is not expanding. This is also a myth. They are both theories...and not very good ones either."Unquote.

Hmmm " the Universe is NOT expanding"  why does he say this? Because he believes in God, as the maker of everything. God makes no mistakes, hence what is know has been forever. The Universe is expanding and we can see this as fact. I will not throw out a claim that something is not so because I say so, as some do. Faith is just that faith, but science works a wee bit different.

Thanks for attempting to explain my words.  Actually, my thoughts have nothing to do with my Faith.  The reason I say what I say is that I believe it to be preposterous to even think that we have a clue about the origin of something that is so incomprehensibly infinite as the Universe.   We can't even get our 'computer's' minds around it...much less our own.
There are literally Trillions of Galaxies...each containing Billions of Star Systems....each Star System many light years away from each other....to even postulate that it is 'expanding' is ludicrous....how could we know...despite the best calculations of astronomers...one cannot say for 'certain' that the Universe is Expanding...what we can even see of the Universe is akin to seeing one inch in front of your face while walking in the midst of a sand storm in the Sahara Desert.

[Torgo]

joc on Dec 13 2007, 12:07 AM, said:

Thanks for attempting to explain my words.  Actually, my thoughts have nothing to do with my Faith.  The reason I say what I say is that I believe it to be preposterous to even think that we have a clue about the origin of something that is so incomprehensibly infinite as the Universe.   We can't even get our 'computer's' minds around it...much less our own.
There are literally Trillions of Galaxies...each containing Billions of Star Systems....each Star System many light years away from each other....to even postulate that it is 'expanding' is ludicrous....how could we know...despite the best calculations of astronomers...one cannot say for 'certain' that the Universe is Expanding...what we can even see of the Universe is akin to seeing one inch in front of your face while walking in the midst of a sand storm in the Sahara Desert.

We can tell the universe is expanding because of three separate lines of evidence.

Firstly, we see a redshift of far away galaxies.  The light from their stars has longer and longer wavelengths the further away they are from us, all the way down to infrared and microwaves for the furthest ones we can detect at all.  This can be construed as being from the Doppler effect, where the light of things moving away from us is stretched as it is emitted.  It can also be construed as space stretching and in the process lengthening the wavelengths.  Either way it indicates the universe is expanding.

Secondly, we can only see a finite distance away in space.  Since light has a finite speed, we are also seeing back into a finite time.  As we look closer and closer to that distance we see different things.  Galaxies behave differently, and things are denser as a whole.

Thirdly, at the very limit of what we can see, we see the cosmic microwave background radiation.  This is a rather uniform microwave radiation coming equally from every direction in the sky.  It has a characteristic spectrum.  A little background:  All objects emit radiation just due to thermal energy.  This light radiation has a peak emission rate at a wavelength that goes down as temperature goes up, and a shape that changes with temperature as well.  When we look at the background radiation, it has a peak at the LOONG wavelength microwaves - but is shaped like the emission curve for a very hot gas, hot enough to ionize hydrogen.  Thus, the universe was, about 13.7 billion years ago (we can tell from the redshift, it increases at a well understood rate with distance and thus duration back in time) , extremely hot and since then the radiation has redshifted on its way everywhere.

Together this indicates the universe used to be denser and 13.7 billion years ago was extremely hot.  If we run the rate of expansion back we see that the observable universe would've occupied zero volume 300,000 years before the furthest radiation we can see - but the furthest radiation we can see indicates that it was released from a plasma which blocks light.  We will never be able to directly see further back than that - but with this evidence it is safe to assume that the big bang (or at least some sort of expansion from a very hot and dense state) took place.

[sumthingnice60]

joc on Dec 12 2007, 09:07 PM, said:

Thanks for attempting to explain my words.  Actually, my thoughts have nothing to do with my Faith.  The reason I say what I say is that I believe it to be preposterous to even think that we have a clue about the origin of something that is so incomprehensibly infinite as the Universe.   We can't even get our 'computer's' minds around it...much less our own.
There are literally Trillions of Galaxies...each containing Billions of Star Systems....each Star System many light years away from each other....to even postulate that it is 'expanding' is ludicrous....how could we know...despite the best calculations of astronomers...one cannot say for 'certain' that the Universe is Expanding...what we can even see of the Universe is akin to seeing one inch in front of your face while walking in the midst of a sand storm in the Sahara Desert.

The universe is expanding because we have methods to tell that galaxies are moving away from us, as explained by torgo. What is even more surprising, and perhaps counter-intuitive, is that the galaxies are actually accelerating which means that there is a strong gravitational field attracting all of the galaxies.

EDIT : torgo explained most of it.

Edited by sumthingnice60, 13 December 2007 - 06:14 AM.