Summary: Because the energy of the Big Bang was moving, and the Schwarzschild radius is for stationary mass.
And I'm sorry, but this explains NOTHING. Even for moving mass the density was enough to make a black hole.
So presumably the density never actually got that high, or there is some other explanation we are not aware of.
He should have just said: We don't really know. Because we don't. Why is there this requirement that science be able to explain everything?
Is it because it's held up as an alternative to religion so people are petrified that if there are any holes people will say "sciences knows nothing, back to religion"?
(Now that I've setup my strawman I'm going to knock it down.)
First of all Science and Religion are not competing for adherents. You can believe that God created the universe and still want to investigate how he did it, and what the details are. Even if you believe the Big Bang never actually happened (i.e. it's an off-camera backstory), you can still be interested in investigating it because if God made it look like that then it's important.
Second the whole point of science is saying "I don't know", otherwise it's a religion, not science.
What he was saying is, if there was just 1 gram per cubic cm less mass in the original universe, then it would expand too quickly to form any complex structures and the universe as we know it would not exist. And if it was just a few grams per cubic cm more massive, then it would collapse immediately as in the original question.
The reason our universe did not immediately collapse is not a mystery. It was a tiny amount less massive than would be required for such a collapse.
The reason it was perfectly on the line is no mystery whatsoever: if it were one gram over, it would collapse, and we would not exist, and thus we would not be asking the question. Same if it were one gram less; the universe would be too sparse for life to organize.
This is not a miracle or a mystery, it's simply fact. Billions or trillions of universes might have sprung into existence over billions or trillions or perhaps even infinite aeons of time, each with different masses and parameters of physics.
The one that produced an observer was observed. That's us, and that's it. No miracle, no mystery.
It's like someone winning a lottery. The chances of a specific individual winning are next to nothing, but the chances of anyone winning are 100%. If a news crew then goes and finds the winner, they will surely find an astounded, surprised, and very lucky feeling person. But the news crew will not be surprised, since their observation is entirely expected and even guaranteed.
Humanity is both the winner and the news crew in this situation, by the simple property of our ability to observe our own existence.
This is called the anthropic principle. It also applies with zero modification to the question of why Earth appears to be such a perfect planet to support human life, especially as we begin to discover that there are literally trillions of planets in our universe. We should not be surprised that we observe the one that happened to have the conditions conducive to the evolution of a sentient observer. But you could be forgiven for feeling very lucky that you're one of them.
That summary is not entirely correct. It's not because everything was moving, but because space was getting bigger. A very different phenomenon.
Why should he say that he does not know when the best accepted theory fits reality almost perfectly on that case? The correct thing to say is that he knows.
Also, if you look carefully enough, we know of no matter that escaped the Universe, as far as we know, it fits exactly the property of the Schwarzschild's black holes.
>So presumably the density never actually got that high, or there is some other explanation we are not aware of.
density don't need to be high to get a black hole - the more the mass the less its minimal density has to be when black hole can be formed - the Schwarzschild radius of our Universe (which is mostly space with the specks of matter) is on the scale of 10B+ light years for example. So depending on how it is calculated and a lot of other stuff - we still can be inside expanding black hole :)
>First of all Science and Religion are not competing for adherents.
In practice, how are they not? There are at least 3 major classes of popular religions that claim that the earth is only 6000 years old, among a smattering of other objectively false claims. One cannot correctly claim these facts are or might be true and also observe the scientific method.
Yes, a hypothetical religion that posits nothing more than "there is a god" would not technically directly contradict the known body of scientific knowledge, but it would still contravene the scientific method.
> Even for moving mass the density was enough to make a black hole.
You are making an assumption here that is debatable.
We understand very little of the physics close to the Big Bang. Those scales in energy, time and space are so extreme that quantum effects are expected to be dominant.
However, all theory about black holes uses general relativity, which does not account for such scales.
It is still an open problem to unite quantum physics and general relativity (i.e. this is basically what string theory hopes to achieve).
> And I'm sorry, but this explains NOTHING.
I think the point is that the assumption made to derive the theory about black holes from general relativity are just not met. The Schwarzschild radius is not defined for non-static spacetime, so it does not apply here.
It is true that it explains nothing, but it also means that you cannot use the Schwarzschild radius in your argumentation.
"one part in 10^24, which is kind of like taking two human beings, counting the number of electrons in them, and finding that they’re identical to within one electron"
I hate to be pedantic... wait, I LOVE to be pedantic.
If you consider a human being to be a 50kg bag of water, that's 2750 moles of water, or ~1.7 * 10^27 molecules. Each molecule has ten electrons, so this factoid is off by about four orders of magnitude. More if the person had a big bowl of electrons for breakfast that day.
Superficially interesting article, but it didn't actually answer the question very well. As near as I can tell from this article, the answer is basically "because it was expanding". It then went into a discussion about the possible behaviors of the universe over time, i.e. expanding indefinitely, having its expansion rate become static, or collapsing. But this discussion is tangential to the question.
I also don't like how the discussion at the end was phrased. It started talking about fine tuning and making a mathematical argument as to the chances that our universe would have exactly the amount of mass it does (which I believe makes the assumption that the mass in our universe is random, though it was never stated). The problem with this is it's basically the argument that our universe must have been made by some external entity (i.e. "God"), without actually saying as much. I say this because there's no other good reason to try and make claims about the statistical likelihood of our universe having the initial conditions it did. And of course, it completely failed to mention that of course the universe's conditions are just right for it to have produced stars and planets and eventually life, because otherwise we couldn't be talking about it. There's a pithy name for this, but I forget what it's called. It also failed to mention the trivial solution to getting a universe that's fine-tuned just right, assuming random initial conditions, that doesn't require invoking any kind of supernatural being: infinite universes.
> What’s remarkable is that the amount of fine-tuning that needed to occur so that the Universe’s expansion rate and matter-and-energy density matched so well so that we didn’t either recollapse immediately or fail to form even the basic building-blocks of matter"
Or perhaps there is an infinite number of Universes and big bangs out there, and ours was just one of the possibilities, while billion other big bangs "failed" in recreating our conditions.
A question: So how far more complex, and fine tunned must be the outer universe so it could fork inner universes? Because then the outer universe purpose is build universes. And must be solid enough to not be corrupted by the inner universes badly laws. So, a operating system?.
This make the answer far more complex, just to try to avoid the fine tunned of the universe, methinks.
IMHO, that was a very long-winded non-explanation. Basically the "answer" comes down to this:
1. We really don't know. We don't understand the rules of physics well enough to model the behaviour of stuff in such "extreme" situations.
2. If you still insist on asking that question, I could give you a plausible explanation of why the question is not really the right thing to ask: "small" black holes tend to evaporate very quickly through the process of Hawking radiation -- in effect producing photons, matter, and every possible kind of "stuff". So even if there was something akin to a black hole, early in the universe, (and if we could apply our rudimentary understanding of gravity and quantum mechanics to even talk about black holes and Hawking radiation) it wouldn't trap the stuff for long... in fact it would be spewing out stuff in copious amounts, and very quickly at that.
Doesn't this question have something to do with uniform distribution of matter and energy in the early universe ? The details elude me right now, but I heard a talk/panel discussion about this - basically the hypothesis presented was that in the early universe, matter had a very uniform distribution as it was confined to a very tony space. This means a black hole could not have formed since there was no point whose gravitational force was greater than any other point.
Maybe the OP is saying that at the big bang, there was our present universe, and it was small, maybe the size of our solar system, maybe a baseball, maybe smaller.
But, whatever, it was small, and, most important, that's all there was. There was nothing more. It was not a very dense, very hot chunk of matter-energy, whatever, inside some larger space. Instead, that's all the space there was.
Then the OP is saying that in that context, where the whole universe was just that ball, the old arguments on forming a black hole don't hold. Instead, what happened was, space itself, that is the whole universe itself, explosively expanded. And it's still expanding.
So, what was that universe 'inside' and what has it been expanding 'into'? Either these are poorly posed questions, or we don't know, or, for the question in the OP, it doesn't matter.
If our universe was inside a "black hole" seen from the outside, how would we ever know?
For al we know the percieved timescale of the big bang and the time since it is just timedialation, and that black hole might even exists in more than 3D.
What if the universe is a black hole, with a very big (and growing?) Schwarzschild radius? That nothing can escape a black hole does not mean nothing can't exist within a black hole ...
Maybe there are millions of other fecund universes where their big bangs did fail for lack of enough mass or enough energy to move fast enough or too fast to form atomic bonds.
So just like life in our galaxy may be a one in million chance, our universe it itself may be a one in a million chance.
I think it's not a probabilistic matter, but more a way of framing Occam's razor. If you allow enough "tunable" variables with just the right values you can easily make a theory fit any observation. For this reason theories including variables requiring a lot of precision to generate our universe are looked with distrust by physicists, I believe.
simpler question - the Universe's end game - given currently observed dynamics does it lead to one gigantic black hole inside very thinly expanded very cold vacuum (with CMB temperature practically 0 instead of 2.7 degrees K today) or to many of such black holes and what would be their distribution?
Black holes eventually evaporate due to Hawking radiation. The current thinking for the very-long-term fate of the universe is the "Dark Era:" nothing except photons, neutrinos, and the occasional electron or positron.
[+] [-] ars|11 years ago|reply
And I'm sorry, but this explains NOTHING. Even for moving mass the density was enough to make a black hole.
So presumably the density never actually got that high, or there is some other explanation we are not aware of.
He should have just said: We don't really know. Because we don't. Why is there this requirement that science be able to explain everything?
Is it because it's held up as an alternative to religion so people are petrified that if there are any holes people will say "sciences knows nothing, back to religion"?
(Now that I've setup my strawman I'm going to knock it down.)
First of all Science and Religion are not competing for adherents. You can believe that God created the universe and still want to investigate how he did it, and what the details are. Even if you believe the Big Bang never actually happened (i.e. it's an off-camera backstory), you can still be interested in investigating it because if God made it look like that then it's important.
Second the whole point of science is saying "I don't know", otherwise it's a religion, not science.
[+] [-] calinet6|11 years ago|reply
This image tells it all: https://d262ilb51hltx0.cloudfront.net/max/953/1*QXypiHUwjJZr...
What he was saying is, if there was just 1 gram per cubic cm less mass in the original universe, then it would expand too quickly to form any complex structures and the universe as we know it would not exist. And if it was just a few grams per cubic cm more massive, then it would collapse immediately as in the original question.
The reason our universe did not immediately collapse is not a mystery. It was a tiny amount less massive than would be required for such a collapse.
The reason it was perfectly on the line is no mystery whatsoever: if it were one gram over, it would collapse, and we would not exist, and thus we would not be asking the question. Same if it were one gram less; the universe would be too sparse for life to organize.
This is not a miracle or a mystery, it's simply fact. Billions or trillions of universes might have sprung into existence over billions or trillions or perhaps even infinite aeons of time, each with different masses and parameters of physics.
The one that produced an observer was observed. That's us, and that's it. No miracle, no mystery.
It's like someone winning a lottery. The chances of a specific individual winning are next to nothing, but the chances of anyone winning are 100%. If a news crew then goes and finds the winner, they will surely find an astounded, surprised, and very lucky feeling person. But the news crew will not be surprised, since their observation is entirely expected and even guaranteed.
Humanity is both the winner and the news crew in this situation, by the simple property of our ability to observe our own existence.
This is called the anthropic principle. It also applies with zero modification to the question of why Earth appears to be such a perfect planet to support human life, especially as we begin to discover that there are literally trillions of planets in our universe. We should not be surprised that we observe the one that happened to have the conditions conducive to the evolution of a sentient observer. But you could be forgiven for feeling very lucky that you're one of them.
[+] [-] marcosdumay|11 years ago|reply
Why should he say that he does not know when the best accepted theory fits reality almost perfectly on that case? The correct thing to say is that he knows.
Also, if you look carefully enough, we know of no matter that escaped the Universe, as far as we know, it fits exactly the property of the Schwarzschild's black holes.
[+] [-] trhway|11 years ago|reply
density don't need to be high to get a black hole - the more the mass the less its minimal density has to be when black hole can be formed - the Schwarzschild radius of our Universe (which is mostly space with the specks of matter) is on the scale of 10B+ light years for example. So depending on how it is calculated and a lot of other stuff - we still can be inside expanding black hole :)
[+] [-] wyager|11 years ago|reply
In practice, how are they not? There are at least 3 major classes of popular religions that claim that the earth is only 6000 years old, among a smattering of other objectively false claims. One cannot correctly claim these facts are or might be true and also observe the scientific method.
Yes, a hypothetical religion that posits nothing more than "there is a god" would not technically directly contradict the known body of scientific knowledge, but it would still contravene the scientific method.
[+] [-] whyever|11 years ago|reply
You are making an assumption here that is debatable. We understand very little of the physics close to the Big Bang. Those scales in energy, time and space are so extreme that quantum effects are expected to be dominant. However, all theory about black holes uses general relativity, which does not account for such scales. It is still an open problem to unite quantum physics and general relativity (i.e. this is basically what string theory hopes to achieve).
> And I'm sorry, but this explains NOTHING.
I think the point is that the assumption made to derive the theory about black holes from general relativity are just not met. The Schwarzschild radius is not defined for non-static spacetime, so it does not apply here.
It is true that it explains nothing, but it also means that you cannot use the Schwarzschild radius in your argumentation.
[+] [-] coldtea|11 years ago|reply
Well, in abstract no. But then again, they are the result of people practicing them (science or religion), and those do compete for adherents.
[+] [-] idlewords|11 years ago|reply
I hate to be pedantic... wait, I LOVE to be pedantic.
If you consider a human being to be a 50kg bag of water, that's 2750 moles of water, or ~1.7 * 10^27 molecules. Each molecule has ten electrons, so this factoid is off by about four orders of magnitude. More if the person had a big bowl of electrons for breakfast that day.
[+] [-] sarreph|11 years ago|reply
Just being pedantic!
[+] [-] eridius|11 years ago|reply
I also don't like how the discussion at the end was phrased. It started talking about fine tuning and making a mathematical argument as to the chances that our universe would have exactly the amount of mass it does (which I believe makes the assumption that the mass in our universe is random, though it was never stated). The problem with this is it's basically the argument that our universe must have been made by some external entity (i.e. "God"), without actually saying as much. I say this because there's no other good reason to try and make claims about the statistical likelihood of our universe having the initial conditions it did. And of course, it completely failed to mention that of course the universe's conditions are just right for it to have produced stars and planets and eventually life, because otherwise we couldn't be talking about it. There's a pithy name for this, but I forget what it's called. It also failed to mention the trivial solution to getting a universe that's fine-tuned just right, assuming random initial conditions, that doesn't require invoking any kind of supernatural being: infinite universes.
[+] [-] higherpurpose|11 years ago|reply
Or perhaps there is an infinite number of Universes and big bangs out there, and ours was just one of the possibilities, while billion other big bangs "failed" in recreating our conditions.
[+] [-] mamcx|11 years ago|reply
This make the answer far more complex, just to try to avoid the fine tunned of the universe, methinks.
[+] [-] ssivark|11 years ago|reply
1. We really don't know. We don't understand the rules of physics well enough to model the behaviour of stuff in such "extreme" situations.
2. If you still insist on asking that question, I could give you a plausible explanation of why the question is not really the right thing to ask: "small" black holes tend to evaporate very quickly through the process of Hawking radiation -- in effect producing photons, matter, and every possible kind of "stuff". So even if there was something akin to a black hole, early in the universe, (and if we could apply our rudimentary understanding of gravity and quantum mechanics to even talk about black holes and Hawking radiation) it wouldn't trap the stuff for long... in fact it would be spewing out stuff in copious amounts, and very quickly at that.
[+] [-] houseofshards|11 years ago|reply
[+] [-] graycat|11 years ago|reply
But, whatever, it was small, and, most important, that's all there was. There was nothing more. It was not a very dense, very hot chunk of matter-energy, whatever, inside some larger space. Instead, that's all the space there was.
Then the OP is saying that in that context, where the whole universe was just that ball, the old arguments on forming a black hole don't hold. Instead, what happened was, space itself, that is the whole universe itself, explosively expanded. And it's still expanding.
So, what was that universe 'inside' and what has it been expanding 'into'? Either these are poorly posed questions, or we don't know, or, for the question in the OP, it doesn't matter.
Maybe that's what was going on in the OP. Maybe.
[+] [-] nextw33k|11 years ago|reply
If we had the ability to alter the fabric of spacetime, could we shrink that fabric so that the black hole either imploded or exploded?
[+] [-] barrystaes|11 years ago|reply
For al we know the percieved timescale of the big bang and the time since it is just timedialation, and that black hole might even exists in more than 3D.
[+] [-] gonvaled|11 years ago|reply
[+] [-] ck2|11 years ago|reply
So just like life in our galaxy may be a one in million chance, our universe it itself may be a one in a million chance.
[+] [-] chrischen|11 years ago|reply
I thought it wouldn't evolve deterministically? So what is he talking about here?
[+] [-] neduma|11 years ago|reply
https://www.youtube.com/watch?v=2XkV6IpV2Y0&list=PLFs4vir_Ws...
[+] [-] aikah|11 years ago|reply
[+] [-] darkmighty|11 years ago|reply
[+] [-] trhway|11 years ago|reply
[+] [-] millstone|11 years ago|reply
[+] [-] MAGZine|11 years ago|reply
As far as science is aware, anyhow.
[+] [-] jsonmez|11 years ago|reply