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View Full Version : Pick this analogy apart, please.


Gawdzilla
16th January 2011, 06:20 AM
I'm not interested in defining this idea to the death, I'm just wondering if has any plausibility. So feel free to chew it up and spit it out.

Imagine there is an extremely complex machine, an thermonuclear bomb. It is in a stable state and following it's own "rules".

Then, it explodes.

In place of the largely static machine we now have an extremely energetic system that rapidly changes as it goes through the various stages of an uncontrolled nuclear reaction.

We have here two "states" that are very different. Unless we can understand the construction of a bomb we don't know what went before the explosion.

Anybody see where I'm going with this?

Safe-Keeper
16th January 2011, 06:34 AM
Anybody see where I'm going with this? Big Bang theory?

Gawdzilla
16th January 2011, 06:49 AM
Big Bang theory?

A crude analogy, yes. The point is that we cannot say what the bomb looked like, how it was built or very much about except for the results of the explosion. Reverse engineering a bomb from the explosion is a real challenge. Doing it for a "bomb" that resulted in an entire universe is more of a challenge.

TubbaBlubba
16th January 2011, 07:00 AM
It's much easier and infinitely harder if the bomb in question must have been a singularity.

Gawdzilla
16th January 2011, 07:19 AM
It's much easier and infinitely harder if the bomb in question must have been a singularity.

The question of scale is daunting, very true. I'm wondering if this will give us a means of getting the issue inside the horizon of most humans.

Mirrorglass
16th January 2011, 07:43 AM
I'm not sure what you're looking for. The analogy is fine, to illustrate the point of how difficult it is to study the early history of the Universe. But I don't think that particular point has ever been a major roadblock in spreading understanding about cosmology.

Gawdzilla
16th January 2011, 07:48 AM
I'm not sure what you're looking for. The analogy is fine, to illustrate the point of how difficult it is to study the early history of the Universe. But I don't think that particular point has ever been a major roadblock in spreading understanding about cosmology.

Ah, it's from a debate over at historum.com. A gentleman keeps demanding to know what happened before the big bang. While I will probably never change his opinion on the matter I do want to give the peanut gallery something they can wrap their heads around as the complexity of the subject.

TubbaBlubba
16th January 2011, 07:50 AM
There is no before the Big Bang, just as there's no north of the north pole. Time started at Big Bang.

Gawdzilla
16th January 2011, 07:55 AM
There is no before the Big Bang, just as there's no north of the north pole. Time started at Big Bang.

And the analogy would be that the bomb was sitting there inert, doing nothing.

Skwinty
16th January 2011, 08:07 AM
just as there's no north of the north pole..

Any thing north of the celestial or galactic north pole?

Or is this just as meaningless?;)

TubbaBlubba
16th January 2011, 08:17 AM
And the analogy would be that the bomb was sitting there inert, doing nothing.

Not exactly, it wasn't "sitting there", it wasn't anything until it exploded (until space-time expanded).

Mirrorglass
16th January 2011, 08:18 AM
Ah, it's from a debate over at historum.com. A gentleman keeps demanding to know what happened before the big bang. While I will probably never change his opinion on the matter I do want to give the peanut gallery something they can wrap their heads around as the complexity of the subject.

Ah, I see. Then I think the analogy should work just fine. If the people hearing want to understand, they will.

Mirrorglass
16th January 2011, 08:20 AM
Not exactly, it wasn't "sitting there", it wasn't anything until it exploded (until space-time expanded).

I don't think that's quite right. More like, it was everything, or the potential for everything, all packed into a singularity.

TubbaBlubba
16th January 2011, 08:22 AM
I don't think that's quite right. More like, it was everything, or the potential for everything, all packed into a singularity.

The problem is that you can't really define a "when" before it expanded, or indeed, a "before it expanded", so you can't define a point in time where it was "everything", since time started when it started expanding.

Mirrorglass
16th January 2011, 08:31 AM
The problem is that you can't really define a "when" before it expanded, or indeed, a "before it expanded", so you can't define a point in time where it was "everything", since time started when it started expanding.

Sure, but doesn't that apply equally to what you said? There never was a time when it wasn't anything, either.

I don't really see what time has to do with it, anyway. Just because there "was" no time doesn't rule out some form of existence. And my (admittedly cursory) understanding of the current views on the origin of the Universe is that in a sense, everything that now constitutes our Universe "was" packed into the singularity.

This may be semantic quibbling, of course, as it isn't really possible to accurately describe an environment outside the Universe in English.

TubbaBlubba
16th January 2011, 08:39 AM
Hmm. I suppose it could be said that at t = 0, all that would come to be was a singularity. At t = 0 + 1 planck time this singularity was no more.

Gawdzilla
16th January 2011, 08:54 AM
I'm proposing to use "the bomb" itself as that indescribable "thing" that came before everything.

TubbaBlubba
16th January 2011, 08:57 AM
At t = 0, there was a point. Space had the dimensions x, y, z, t = 0, 0, 0, 0. I'm not entirely sure your analogy is entirely valid, as the universe wasn't "complex" in any meaningful sense of the world.

Gawdzilla
16th January 2011, 09:01 AM
At t = 0, there was a point. Space had the dimensions x, y, z, t = 0, 0, 0, 0. I'm not entirely sure your analogy is entirely valid, as the universe wasn't "complex" in any meaningful sense of the world.

If it was entirely valid I would be the first one to faint in surprise. :cool:

bokonon
16th January 2011, 09:45 AM
At t = 0, there was a point. Space had the dimensions x, y, z, t = 0, 0, 0, 0. I'm not entirely sure your analogy is entirely valid, as the universe wasn't "complex" in any meaningful sense of the world.
It's probably the case that either you don't understand it, or you do but won't be able to explain it in a way that I'll understand, but...

What is the justification for claiming this dimensionless singularity? How do we know the big banger wasn't the size of seven galaxies before the expansion we call the Big Bang?

Certainly, if we considered the aftermath of Gawdzilla's bomb, if it flung matter out in an expanding sphere, someone seeing this expansion could infer that the sphere had previously been more compact. Why is it necessary to assume a series of more compact states that extends all the way to dimensionless? In the case of the bomb, that assumption is clearly incorrect. What justifies it in the case of the universe?

TubbaBlubba
16th January 2011, 09:54 AM
It's probably the case that either you don't understand it, or you do but won't be able to explain it in a way that I'll understand, but...

What is the justification for claiming this dimensionless singularity? How do we know the big banger wasn't the size of seven galaxies before the expansion we call the Big Bang?

Certainly, if we considered the aftermath of Gawdzilla's bomb, if it flung matter out in an expanding sphere, someone seeing this expansion could infer that the sphere had previously been more compact. Why is it necessary to assume a series of more compact states that extends all the way to dimensionless? In the case of the bomb, that assumption is clearly incorrect. What justifies it in the case of the universe?

Not entirely sure. I think it's based on assumptions that an extremely compact universe would collapse a la a black hole, but our current physical theories can't describe singularities very well, or at all, really.

A physicist will probably give you a better answer. I'm only a slightly-better-than-average-read layman.

bokonon
16th January 2011, 10:04 AM
Okay, thanks. I don't understand it either. That's why I'm maybe more sympathetic than most here to the argument from the other side that my origin belief is just as much a "faith" position as the position of those who subscribe to "In the beginning...".

HansMustermann
16th January 2011, 10:08 AM
I don't think you have to even go as deep into it.

Forget t=0, there is some time even after it when the universe is opaque to light. (A super-heated soup of unbound protons and electrons is.) There is no light reaching us from before the universe went transparent. And that's estimated to have happened almost 400,000 years after the big bang, when the universe had expanded enough to cool down to "only" a few thousand kelvin and the electrons started orbiting around the nearest proton instead of ricocheting around at incredible speeds. (Think: "only" about as hot as the sun;))

Any gravitational waves or such, if existent at all from that time, are also likely to be scattered to heck and back through that particle soup and more likely to be from local non-homogenity than any carrier of information.

Basically the honest answer is: we don't bloody know what happened before that time. We can take a very educated guess based on the physics we know at the moment, but we don't have any actual information for even the first 400,000 years or so of the universe, much less about what came _before_ it.

In a sense, the nuke going off is actually a good illustration. Very quickly you get a bubble of superheated air around it, that is opaque to light. (Though quite bright itself, as it's many thousands of degrees hot.) You can't actually see most of the actual explosion behind that bubble, until it expanded enough and cooled down to the point where it's transparent again.

HansMustermann
16th January 2011, 10:15 AM
Okay, thanks. I don't understand it either. That's why I'm maybe more sympathetic than most here to the argument from the other side that my origin belief is just as much a "faith" position as the position of those who subscribe to "In the beginning...".

The difference, however, is that we measured a lot of stuff and that big bang is the conclusion of measured data and verified science (to the best of our current knowledge and abilities.) It's not like someone woke up one morning and decided to take it on faith that the universe had a beginning.

In fact, quite the contrary. Most of the history people wanted to assume that the stars are immutable, and the universe outside us and the known planets is unchanging. Even those believing in some form of "in the beginning", imagined the gods or spirits or whatever creating those, but afterwards they just stay as they are. Even as late as the 20'th century, that's why Einstein introduced his cosmological constant, to enforce an equilibrium and a universe that is neither contracting nor expanding.

That the data points out to an expanding universe was actually a fairly hard pill to swallow, and for some people it still is. We didn't do that willy nilly.

Which brings me to the more important part why it's not faith: we're willing to amend that model when/if new data says otherwise. We introduced a Big Bang when enough data pointed at that, and we'll take it back out and replace it with something else if/when new evidence says something else.

Unless you found some sect that's willing to replace Genesis with whatever the current evidence points at, science is nothing like those who take "in the beginning" on faith.

I Ratant
16th January 2011, 10:19 AM
We have experience with nukes, and understand their processes.
We have only the single data point for this universe.
It's here.
No previous experience with other similar or dissimilar universes.
Look at a reasonable number of these to find any similarities or trends, or typical performances.
Get funding.
That will be a task! :)

marplots
16th January 2011, 10:49 AM
You're really trying to get at the difficulty of determining just what happened historically when there is no good footprint to track it with.

My analogy would be asking, "Well, what was your body before you were born?" This gets at the idea of a meaningless question. You might also point out that the rules of physics allow us to guess about atoms and where they came from, but it does not let us determine the exact path that led to the physical person sitting in front of a keyboard.

I know this doesn't address the Big Bang in particular, but it does tweak the brain a bit about how we try to "see" back in time and the limitations.

fuelair
16th January 2011, 11:29 AM
And the analogy would be that the bomb was sitting there inert, doing nothing.It migh be better to say time as we know it did not exist before the BB. And we do not know exactly what happened in the first few tiny, tiny, tinyfractions of (what would on this planet long, long years later be called) a second.

Problem with the TN analogy is that only if there is the clear assumption that we know nothing about thermonuclear devices can it be an analogy to the BB.

If a TND detonates, we have the ability to figure out basically how it was set up, what the explosive material was, how much of it there was and IIRC where/what the source of that material was based on the material now present in the blast area. We can't really do that with a mysterious, ancient one-off bangup!!

Gawdzilla
16th January 2011, 12:16 PM
Good points, all of you. Thanks.

bokonon
16th January 2011, 01:07 PM
That the data points out to an expanding universe was actually a fairly hard pill to swallow, and for some people it still is. We didn't do that willy nilly.
I do understand enough of the "expanding universe" evidence to say that I'm not taking it on faith. While I haven't actually peered through a telescope or measured a red shift myself, I have confidence that a number of astronomers have done so and reported their observations truthfully and accurately. Since I understand the evidence and its implications well enough, I can say honestly that my belief in an expanding universe is not based on faith.


Unless you found some sect that's willing to replace Genesis with whatever the current evidence points at, science is nothing like those who take "in the beginning" on faith.
There are certainly scientists who can say they aren't taking the singularity on faith, but I am not one of them. On the matter of the singularity, I am an agnostic, or possibly an ignoramus. I don't know enough about it, or the evidence which supports it, to argue intelligently one way or the other. Maybe I could understand it if I tried, but it's neither important nor interesting enough to me to find out. Whatever happened was a long time ago, and I'm willing to let bygones be bygones.

Delvo
16th January 2011, 04:44 PM
Ah, it's from a debate over at historum.com. A gentleman keeps demanding to know what happened before the big bang. While I will probably never change his opinion on the matter I do want to give the peanut gallery something they can wrap their heads around as the complexity of the subject.The problem is that we could tell a lot of information about a bomb if we had data on the explosion. It consists of a number of photons, nuclei, free neutrons, and other particles. With a knowledge of how particles interact, these "products" of the reaction reveal what kind of reaction produced them, which in turn reveals what particles in what arrangements were there before the reaction and what happened to them to cause the reaction. Loss of ability to calculate what happened before hits not at the time of the reaction, but a few steps before that. For example, if the bomb were the old gun type, it could be determined how much uranium (and/or other radioactive materials) was used, what its isotope ratios were, that two pieces of it (whose shapes we'd have a pretty good idea of) had been slammed together at a known speed, and even the general composition of the surrounding bombshell/detonator (because the atoms that it had been reduced to would still be observable). Only the structure and operation of the mechanism that had caused at least one of the pieces to move toward the other would be lost. The equivalent to that for the Big Band would be being able to hear God say "Let there be light" but being unsure of whether he had an English or Australian accent.

I'm proposing to use "the bomb" itself as that indescribable "thing" that came before everything.God self-destructed?! :jaw-dropp

Gawdzilla
16th January 2011, 05:06 PM
Thanks again. Delvo, gracias! Every problems you folks bring up will be one I'm ready for when my dear Discovery Institute shill comes back.

marplots
16th January 2011, 07:17 PM
One more thought. Although I might not be able to say with any confidence what happened before the Big Bang, it's pretty clear from some 10^-37 seconds afterward. Sounds pretty cool, huh?

Andrew Wiggin
17th January 2011, 03:49 AM
God self-destructed?! :jaw-dropp

I have preached that concept to christians as part of the 'I listened to you babble, now you have to listen to me babble' concept.

I call it the church of god the curious. God was the guy who pushed the button labeled 'don't push this button' and was instantly destroyed in the explosion. He did it out of boredom and curiosity. The closest mankind can come to godliness is to share god's last thoughts, which were 'Oh expletive, that was stupid'. Services consist of church members comparing scars and telling how they got them.

It generally isn't a well recieved message...

sphenisc
17th January 2011, 04:05 AM
...My analogy would be asking, "Well, what was your body before you were born?" This gets at the idea of a meaningless question..

I think there's a foetal flaw in your argument.

Wowbagger
17th January 2011, 08:08 AM
One more thought. Although I might not be able to say with any confidence what happened before the Big Bang, it's pretty clear from some 10^-37 seconds afterward. Sounds pretty cool, huh?Not good enough!! We must investigate the Initial Condition more!!!

Gawdzilla
17th January 2011, 10:38 AM
Not good enough!! We must investigate the Initial Condition more!!!

Contact Col. Paul Tibbets. :D

fuelair
17th January 2011, 10:49 AM
:di think there's a foetal flaw in your argument.

:d:d

marplots
17th January 2011, 12:38 PM
I think there's a foetal flaw in your argument.

That's because the Big Bang was infantaneous.

KingMerv00
17th January 2011, 01:09 PM
I'm not interested in defining this idea to the death, I'm just wondering if has any plausibility. So feel free to chew it up and spit it out.

Imagine there is an extremely complex machine, an thermonuclear bomb. It is in a stable state and following it's own "rules".

Then, it explodes.

In place of the largely static machine we now have an extremely energetic system that rapidly changes as it goes through the various stages of an uncontrolled nuclear reaction.

We have here two "states" that are very different. Unless we can understand the construction of a bomb we don't know what went before the explosion.

Anybody see where I'm going with this?

I think the point you are trying to make is fine but there is a minor nitpick that comes to mind.

Bombs start out organized and end up less so. The universe at T=0 was actually simpler than it is now. Entropy was at record lows.

Delvo
17th January 2011, 01:32 PM
I think there's a foetal flaw in your argument.Not as bad as thoe loethal one in your spoelling.

Fontwell
20th January 2011, 05:20 AM
What I find odd is that apparently there are people who need convincing it is hard to investigate the initial conditions of the big bang.

freedy
21st January 2011, 08:17 AM
Let’s try a smaller analogy.
Man saw fire, and learned how to create it from it’s fundamental elements of heat, fuel and oxygen!

Observing a nuclear explosion (or Big Bang) and determining the fundament elements is just a tad harder.