Hey everyone, I'm currently working on a Philosophical Theory thats been circling my overworked (thanks to finals) head.
I'm almost finished, but there is one thing that I need some sort of answer from, and I figured that the space and astronomy section would help me best.
Ok, so heres what I'm asking. Assuming the Big Bang is true, whatever your stance on it is, what do scientists say caused it? Has anyone ever made a scientific attempt to explain it?
I know that in the theory, before the Big Bang all matter in the universe was compressed into a point of space that would essentially be, from our perspective, infinitely massive and dense, yet infinitely small, which, according to my understanding of cosmology (which, alas, is lacking) would not literally mean infinitely, but more or less incomprehensible, as the weight of this one point would be the weight of the entire universe, all focused in on one ridiculously small speck of matter.
I used to be a proponent of the Big Crunch/Big Bounce theory, but the accelerated expansion of the universe made me think otherwise, and I had a bit of a revelation during my philosophy class about the nature of the beginning of the universe. So, since my cosmological knowledge is relatively limited, I'm hoping someone will offer any information (even a yes science has an explanation, or no, it doesn't), any at all at the very least will be most helpful.
Thanks

church...

Ah, I see you are exploring beyond the limits!

We have studied the Big Bang for a long time. It is a seemingly very valid model for the origins of our spacetime and physical universe. However, what caused it is utterly unknown. Scientists can explain what the theory says happened, right from the finite moment in the way distant past, but anything prior that moment in time...the cause, as-it-were, of this sudden, cataclysmic expansion, is not explained.

Science has its limits, and at present, this is one of them.
Utilizing the theory of General Relativity, we can extrapolate the expansion we observe of the universe backwards in time, but we can only do this until the mathematics of the theory yield a singuilarity of infinite density and temperature at a finite moment. That's the Big Bang.

Beyond that, we know nothing at all. It's rather similar to the speed of light. Special Relativity's mathematics stop everything at a point infinitesimally close to the speed of light, but never actually reaching the speed of light, let alone exceeding it. Basically, you can't go any faster because the equations do not allow for the square root of a negative number, nor "0" as a result (believe it or not...that's what the cosmic speed limit boils down to...when velocities greater than "c" exist, and "0" occurs in the equations, which is what time and the length of objects at "c" are, we arrive at an impossibility. At that point, we have reached a limit, mathematically.


We can use Special Relativity to get us right up close to the speed of light, and General Realativity can get us all away to the point of the Big Bang...pretty big speeds and pretty big time frames, granted, but beyond them, we know nothing at all.

So, I think the answer is that no, science doesn't have an explanation for the cause of the big bang. The cause, according to definition of the term, was in existence prior to the event, and since we can't see beyond the point of the event...we don't actually know.

At this point, "mind and will and hand of God" is as good an explanation as anything else...

Thanks, this helps alot. I wasn't questioning the Big Bang theory, I am a strong supporter of it, I was just seeking some further clarification on it.

Oh no, church...I didn't think you were questioning it. I was actually adressing the depth of your thought in going beyond the limits of modern science in your queries.
I think that's a healthy way to be!

Good luck with your Philosophical Theory!!

Didnt Einstein say nothing can travel faster then light due to friction, or something like that, even in space where there is close to none, once you get to that speed an object the size of a ball point pin will be.... well I dont know, pretty damn big.
Im sure you understand and can explain what I am saying a hell of a lot better then me though.

Oddly enough, Special Relativity predicts that as an object nears the speed of light, it will shrink in respect to its length in the direction of motion, relative to the stationary observer, not get bigger. Clocks also slow down in the same fashion, and by the same relation...

(1 / square root of (1 - velocity squared / speed of light squared))


We cannot attain the speed of light because if velocity in the relation above is = the speed of light, the relation becomes the square root of zero...which of course is zero...meaning something would have no length and time would cease to exist, which of course isn't possible for an object in space. Thus, "c" is unattainable. And of course, making velocity > "c" would result in the square root of a negative number, which is not a real number...thus, you can't attain or exceed the speed of light, according to Special Relativity...

Of course, none of the changes would be perceptible to the person who was actually moving!
...wierd stuff, eh?

It's really that bottom-line simple....of course, understanding the derivation of that relation takes a little more than basic algebra. Einstein wrote a popular exposition on Relativity in 1916, in which he said that it assumed a level of education which corresponded to that of a college matriculation exam. I think today perhaps that might be a little shy of the real requirement.

If you're actually interested, the book is called, oddly enough , RELATIVITY, Albert Einstein (1916) (c. 1961, the estate of Albert Einstein). It's relatively short (no pun intended), at about 155 pages or so, but it will take some patience and effort, and a knowledge of algebra at least to get through it. It's elegantly simple, really!


Einstein was a great teacher, as well as a great Physicist....

we humans are the event that puts speed limits on all things there is no speed limit in the unknown.

Actually, it's mathematics that results in the speed limits.
Of course, humans invented mathematics. Personally, I am of the mind to continue to question "why". I also feel strongly that the current limits of our models and understanding, as valid as they seem to be for the conditions we observe and predict, will be refined, and one day, we may indeed find that there is a new mathematics that can justify speeds in excess of "c".


However, semantically, I must take exception to your comment, since the "unknown" implies that we don't know anything about it. Thus, logically, it can only be inferred that we don't know anything about speed limits in such a place as the unknown...nor do we know anything at all about the unknown....since it is, after all, un-known.

If you know there is no speed limit in the "unknown", then the unknown is really not unknown, is it?

I don't know much about this either but I'll throw out some questions to try'n help you. (Hopefully other people could answer some of these)

Would there be time when the universe was infinitesimally small/ how would time work? I think this is important because we always consider that something comes "before" something else which wouldn't really apply if there was no time.

What is matter, and what is energy? Can energy exist without some sort of physical component?

The universe was supposedly infinitely small, what does this mean?

Is the fundamental size of the universe (the smallest possible level that a thing can exist in) infinitesimal or finite?

Just some questions to consider when trying to find out how/why the big bang would happen, I think... what college do you go to, by the way?

Perhaps the Big Bang was the end of something and not the beginning. That end brought forth an expansion of time, matter and space.

Or perhaps somehow in a seemingly forward motion - time, matter, and space are now in a reverse motion towards a new beginning.

Humans could be experiencing the beginning of something that we are a part of that we are experiencing in an illusion of foreword motion.

If we look at things in a non progressive manner then maybe a few mysteries will be revealed.

No. Time didn't exist at that point as we know it. Everything is measured from the moment of the Big Bang, including our concept of time. Further, I should suppose it doesn't apply to the Big Bang because no one knows anything about anything "before" that moment.


However...as in most such abstractions, I'd be willing to bet someone could argue for time before time.



We can say that broadly speaking, matter is anything which occupies space and has mass....however, the definition of matter is still the matter of some debate and frankly, there really isn't a broadly accepted definition in the scientific sense. It's actually pretty heady stuff...

Energy is generally defined as the ability to do work. That too is the topic of some pretty heady discussion. Energy is a property of objects and systems. Thus, one could certainly argue that energy with out matter is a non-thing.

...Although I have this feeling that a theoretical physicist might have a field day arguing the contrary!!!



Infinitely small means reduced to a dimension that is immeasurable. Theoretically, one can reduce something infinitely by continually making it say, 1/2 the size it is at present. It's never "nothing", just infinitely reduced.



I would be inclined to say infinitesimal,based upon the principal above. However, given the current understandings of sub-atomic particles and their sizes, one could also argue for a finite limit on smallness. The fact is, our understandings have limits, but the universe itself may not.



Well, physicists haven't even gotten close to the answer to that question...but your questions certainly could spark some intense contemplation!




Who?

MID what about the post 10, could it be we are all but a small atom sized event happening all inside a universe of atoms ? size does matter I think. just thinking too much. maybe if I put a camera on my back I`ll catch the truth. LoL DONTEATUS Great post Mid

i have my theory about how the universe started but i only agree with some parts of the big bang theory but in general i think that the big bang it self didnt happen

As I understand it attaining the speed of light is theoretically impossible because: When an object accelerates it gains mass, which requires more energy input,so theoretically to accelerate anything with mass to the speed of light would require an infinate amount of energy. This is not a great explanation but it is described by Einsteins formula E=mc2, as well as calculating energy potential it can be applied to acceleration.

So to calculate the energy required to accelerate to a certain speed you take the mass (m) x velocity (c (usually sol)) squared. Its a bit more complex than that and the actual calculation would be differential but for a simple explanation It'll do, until someone corrects me its been ages since I have dealt with that.

As for what caused the big bang, yeah thats a tough one, to which I don't think there is any great explanation beyond the staple 'all laws of physics break down in a singularity'. That said there are some quite disturbing questions raised by this. There are thought to be many singularities thoughout the universe, which are not defined so much by their mass as by the amount of mass concentrated within a particular area of space, the stilleto effect. Most singularities are a few solar masses (one solar mass being equal to our star) but there are supermassive black holes at the centre of many galaxies that are estimated to be thousands if not hundreds of thousands of solar masses. If the Big Bang occurred by some unknown property of a singularity whats to say a smaller but quite catastrophic explosion of similar proportions will not occur from any other singularity?

Others of some scientific standing have though the very same thing, D....

Actually, the mathematics involved with Special Relativity are elegantly simple.
Above, a little ways, I discussed the speed limit of "C":




If you actually take the time to study Einsten's own work, and you get down to the bottom line of this cosmic speed limit stuff...you just kind of sit there with your mouth agape and say, "Holy crap...of course!"

It's alot of fun!

The part of the "big bang" that gets me is......if nothing can exceed the speed of light, how come inflation occurred faster than the speed of light!?
Or have I got that completely wrong?

Inflation?

You haven't got it completely wrong. This is part of the horizon problem in the standard model and was first brought up in the seventies. It's not that anything was moving faster than the speed of light but that metrics (how space is described) underwent exponential growth at the speed of light. You can't picture it as moving away from a central point but instead everything moving away from everything at the same moment. This would invariably mean that some areas of the universe would have no causal effect on others because energy from one area would never reach another given constant inflation. This is based on the fact that the speed of light is dependent on a single inertial frame. Yet you arrive at any inertial frame moving away from another at the speed of light. They could never meet. That's kind of simplified but it suffices. This would also imply that the universe should not be so homogenously close in temperature. The problem is solved by inflation through quantum fluctuations. Meaning, at that point in the universe, fields would adhere to quantum fluctuations not the general standard model. The predictions of the inflation model solved a ton of problems and has since had a bunch of it's predictions confirmed, such as homogenous background radiation. What it comes down to is in first instances of inflation the universe followed the laws of quantum physics and was already acting like, say, a volume of gas with differing areas of temperature. It homogenized quickly and the slight areas that didn't were the areas that formed collections of matter that later became galaxies and such. This early homogenization should have remanents near the hubble limit and this is what we see.

I know this all sounds pretty wacky. Something that is not often brought up is that the inflation model also implies a universe much, much larger than the visible universe. What we see of the universe is within the hubble limit. Outside of that there still remain metrics that had no causal reference on us. Meaning, due to exponential inflation the fields there can never propogate past the hubble limit. No wave, field, or anything bound by C (which is everything as we understand it) can reach us due to exponential inflation at C during the inflation event.

Well, I don't know if I cleared anything up or made it worse.

Thanks capeo, I've read and reread your post several times......but alas, I still don't really get it!
What do you mean by "exponential growth at the speed of light"? I understand what exponential growth means, but not the complete sentence!
What I mean is.....exponential means accelerating and not linear, whereas the speed of light is constant.

I decided to do a Google on the subject and found Inflation for beginners.
I had to chuckle to myself.....for beginners? yeah right! clear as mud! lol
There is a paragraph that suggests that the expansion does exceed the speed of light, but it's spacetime that does this not matter.

capeo or anyone, is there a way of describing this theory that is more understandable to the cosmologically challenged!?

There is another way of looking at the Big Bang theory.
In String Theory, our universe exists in Calabi Yau space. Calabi Yau space is a multi-dimensional space that exists in anything from 7 to 11 and upto 26 dimensions. In Calabi Yau space there exists 'Throats'. These are regions of space that are wide at the top and get progressively smaller as you travel down (think of a funnel). It has been theorised that, at a distant time in the past, our universe fell down one of these Throats. As the universe travelled down the Throat, it would be compressed into an infinately small point (Big Crunch?). However, because the universe is spinning, its rate of spin as it travelled down would increase until, eventually, Centrifugal Force would force the universe back up the Throat where it would expand again once it had the room. This could be one explanation for the Big Bang event. This would also explain what was here before the universe as we know it. It was the universe.

Correct answer to original thread question.

Yes there is a more fundamental theory behind the big bang. It is known as string theory. (see string theory), In this theory (branes) short for membranes collide and the point of their collisions are viewed as big bangs. In fact youtube has a very nice collection of short films on string theory. I recommend them.

The problem here is that string theory is not accepted by all physicsts, in fact far from it. Actually it isn't even a theory, more of a hypothesis. String theory is a nice attempt to unify the forces of nature and subatomic particles into one theory. However there is currently very little evidence to show whether string theory is correct. Even more problematically there are multiple (and sometimes mutually exclusive) interpretations of string theory. String theory requires more than the three spatial dimensions we are used to. The string theorists argue about how many are required and how they exist.

Then we have brane theory. This is an off shot of string theory. It is fairly new and is not yet widely accepted even by string theorists. It really is just a hypothesis with no evidence to support it... yet.

This at one of the cutting edges of physics. Brane theory and even string theory itself may become accepted or discarded in the next few years. Either way mankind's knowledge will have increased as a result.

No, string theory has been unified, I believe it is called M theory.

All theories are just models which rely on their predictive capacity and or / consistency with known observations as validity.

Do we know if the electrons are really spinning in electron spin ?.
Do we know if there are really quarks inside subatomic particles ?.
Do we know if a one legged duck really swims in a circle?.

Sometimes the model (theory) adds understanding to the underlying process. Sometimes the process gives rise to the theory. It is the old chicken and egg conundrum.
Sometimes new theories or discoveries shed light on old theories, for example Newtons law of gravity explained how to predict the acceleration, velocity and displacement of moving objects. I did nothing for the understanding of action at a distance. Along comes relativity and gives insight into a finite closed and curved universe, now we can see gravity as a straight line following curved space. If a theory is accurate at fitting the data and makes useful prediction, let it stand.

If later we find conceptual problems with it, we can abandon it at that time. There is no absolute truth only series of smaller and smaller useful lies. I advocate acceptance of M theory until it is either disproved by malprediction of violation of previously accepted facts.

If science cannot be wrong, if we can't change our minds, if we just dogmatically accept something as forever and eternally true irregardless of new insight and evidence , If we malign and mistreat everyone that does not share our opinion, then we would have to change our name to Religion.

Your Friend

You make some excellent points. Please elaborate, though. I had thought that "super" string theory and brane theory (M Theory) had concluded that there are 11 dimensions? Or 12? The additional ones (by the way, humans encounter four: length, width, depth, and time) are wrapped up, folded, and twisted on the scale of foamy space. You are absolutely correct that it's hypothesis. Basically, it works with the math, and the math works with the theory. But we'll never be able to "see" that level. It goes against Heisenberg... But elaborate. What are the superstring theorists saying today: Brian Greene and company?

I would disagree with what you said about String Theory being just a hypothesis. I think String Theory is as relevant a theory as Relativity was when it was in its infancy. And yes, String Theory is, basically, still in its infancy, especially compared to Relativity and Quantum mechanics. You also have to remember that String Theory was considered dead at one point and was hardly even thought of during the 70s, it wasn't until mid-way through the 80s that it was taken up again as a viable theory and there has been many significant advancements made in it in the years since then.
True, for String Theory to work properly, it has to exist in many dimensions and most of these dimensions are much smaller than the Planck length and, therefore, almost impossible to prove. However, taking these dimensions as a given, String Theory works remarkably well when applied to models of the universe. That's why it is still the best option as a grand unification theory to date imo.

I do not claim to be any kind of expert on the subject, but it is my understanding is that M theory is a branch of string theory which would unify them if correct. However, yet again, it is highly hypothetical. As there is no empirical evidence to support string theory there can, logically, be no empirical evidence to support M theory.


This is true but string theory has not yet reached that level, it remains purely hypothetical, a mathematical possibility but not yet backed up by observations in the same way that Relativity or Quantum Mechanics are. These have both been tested experimentally. The theories make specific predictions when where then tested and the results found to be excellent fits, Sting Theory has not been tested in the same way, that is why I believe it is only a working hypothesis and not yet theory. One day string theory may be experimentally verified, but not yet.



I'm not sure about the duck, but the other two were predicted and then experimentally verified. We can take this discussion down to the philosophical level, do we really know that anything exists, but then it would no longer suitable for the science board. From a scientific point of view though the Standard Model has been tested time and time again and the experiments appear to confirm it. This is not true of string theory.


Up until here you were making good scientific sense, sadly you ruined it with this one sentence. Science should never EVER be in the business of accepting as fact something for which there is little or no supporting evidence, that is the realm of superstition and religion. IM theory should neither be accepted nor rejected until such time as there is good evidence to make such a decision. It should be treated as what it is a hypothesis... a good but unproven working model.


I agree with you on this point (and have made this very same point many times on this science forum), but it also holds true that if we dogmatically accept a hypothesis arbitrarily, as you seem to have done above, we risk going down the same route. Acceptance of a hypothesis must be on the weight of evidence. If there is no evidence there can be no acceptance however good the hypothesis looks on paper.

I have no problem with string theory, my posts should in no way be considered an attack on it. My point is simply that it remains purely hypothetical and should not be considered fact... yet.

I have a question and maybe somebody can help me with it. I read in a high school textbook today(I collect them btw) and it said that when all the matter came together that it started spinning and exploded thus the Big Bang, the question I have is if this "infintesimile region" was spinning in one direction wouldn't all the galaxies, planets, etc. be spinning in the same direction? Thanks.

Your textbook is wrong.

People (including the people who write the often oversimplified textbooks) have an odd conception that the big bang was directly responsible for every detail in the uinverse. As near as we can tell, what ACTUALLY happened is that the furthest back we can see (the microwave background radiation) the primordial gas was very nearly uniform with only small density differences. These lead large clouds to collapse into the filament-of-galaxies and void structure we see in the universe as a whole. As clouds collapsed further, you got places becoming dense enough for star formation. Depending on the details of that collapse you got galaxies with a lot of spin (spirals) or not much spin (ellipticals) and spin in all different directions. Within all these galaxies, the forces causing smaller clouds to collapse into stars and stellar systems are FAR stronger influences on the eventual orientation of the stars and planets than the galactic spin. Its basically chaotic stochastic steps all along the way causing all these things, not some kind of overall angular momentum of the universe.

Thanks, I don't believe in the Big Bang, but I do like to study up on the subject of evolution and the Big Bang.

All anybody can do is guess. There simply no way of knowing anything at all that was before our universe. This is all we have. All our knowledge comes ffrom what we observe in our universe. Theres just no way to know anything about the physics or conditions of what was before. It would have completely no dimenstions. Thats impossible to even imagine.

family guy's version of it was really funny
god beat this guy at chess and he was farting and he uses a light next to his bottom then he farted and then the galaxies were created. but as we know thats not true but i still dont have a clue about how the big bang started. the next big question is what came before the universe became a super atom and how were the elements created =S

Ah, yes....I believe that is the "Horton Hears A Who" theory, proposed by Dr. Seuss!!