How Come Our Universe Still Exists?

[Railton2]

Hey

 

 

How come our universe still exists?

 

According to what I know our universe was created from a singularity, the big bang, a so called explosion. If everything, including all matter and energy, was created at the time of the big bang, then all matter must have been squeezed together in the first nanoseconds of our universe. How come that there wasn't a black hole, when all the matter from our universe was squeezed into that small place in the first second?

 

If there was a black hole, how come our universe still exists?

 

 

According to what I know, the definition of a black hole is an object so dense, that the gravity is so powerful, that not even light can escape. That means in order for matter to escape from the event horizon created by a black hole, then the matter MUST exceed the speed of light. According to Einstein's theory of relativity; In order for matter to travel faster than the speed of light, then you must need more than an infinity amount of energy. Then how come that the matter escaped from the event horizon at the beginning?

All matter in our universe MUST have travelled faster than the speed of light in order to escape it. Does that mean that all the matter in our universe had more than an infinity amount of energy in the beginning, in order to escape?

 

Why didn't the universe collapse by its own gravity, without using an infinitive amount of energy for the matter to escape?

If there wasn't an infinity amount of energy at that time, then our universe must have collapsed by its own gravity or what?

 

 

How come our universe still exists?

 

Did our universe collapse by it's own gravity?

Could our universe be a black hole?

 

 

 

 

Thanks for reading, I really hope you understand and will answer my questions :D

 

Sincerely,

Mark

 

 

Have a great day!

[joekgamer]

The matter in the universe 'coalesced' after the Big Bang from the energy released y by the Big Bang. It was never 'compressed' together like that. Also, there's a limit to the amount of matter a black hole can hold.

[sanctus]

Also it is a common misconception that the big bang was an explosion somewhere. The Big Bang was everywhere since it created the thing we call space-time ;-). See for instance the 6th paragraph here...

[CraigD]

According to what I know our universe was created from a singularity, the big bang, a so called explosion. If everything, including all matter and energy, was created at the time of the big bang, then all matter must have been squeezed together in the first nanoseconds of our universe. How come that there wasn't a black hole, when all the matter from our universe was squeezed into that small place in the first second?

 

If there was a black hole, how come our universe still exists?

Long answer: study the big bang model, with all the prerequisite physics, really well, then answer the question yourself. :)

 

Short answer: (long breath – this is a tough question for which to come up with a short answer, even if one has “stud[ied] the big bang hypothesis, with all the prerequisite physics, really well”, which I’m still way short of doing :()

1. The universe transitioned from actual (vs virtual – a complicated subject) nothing to something due to “quantum weirdness” – specifically, a large scale vacuum quantum fluctuation, famously proposed in 1969 by Edward P. Tryon (story at this 1994 Harper’s magazine article) and developed fairly seriously by several well and lesser known “nothing theorists” physicists since then.
   
2. Before whatever it is that carries the gravitational force (“gravitons” for lack of a better name, although a big bang-compatible theory of gravity hasn’t yet been found, so this is really just a placeholder name) came into existence, the universe suddenly became much larger – via “cosmic inflation”, another complicated subject
   

 

A minor quibble, and a profound point:

Also, there's a limit to the amount of matter a black hole can hold.

Based on our understanding of how black holes form and the history of the universe, we can estimate the largest black hole that can exists now. However, this is not the same thing as there being a limit to how much matter a black hole can, under other conditions, hold.

 

Really big black holes – the kind found at the center of our and likely every other galaxy – tend to “starve” themselves by blowing matter away with radiation from their accretion zones, limiting how quickly they can grow, and even if they didn’t, the inverse square ([imath]\frac{k}{r^2}[/imath]) nature of gravitation force means they’d clear all the matter from their neighborhood and not be able to attract more for a long time. Were this not the case, however, there’s no theoretical limit to how big a black hole could become – just keep “feeding” it mass or equivalent energy, and it’ll keep getting bigger.

 

There is a limit to how small a black hole can be without quickly “evaporating”, but, counterintuitively, the rate of black hole evaporation (due to a theoretical predicted effect know as Hawking radiation) , but the rate of black hole evaporation (technically, its power) is proportional to the inverse square of its mass ([imath]\frac{k}{M^2}[/imath]) – that is, the larger the black hole, the slower it evaporates.

 

Now for the profound point (a speculation):

Reasonable estimates of the mass of the visible universe and the radius within which it’s contained suggest that the entire universe may be a black hole – that is, us and everything we can and can ever see is within the event horizon of a black hole.

[joekgamer]

But wouldn't there be a point at which the matter in the black hole could theoretically have enough elastic energy (or something similar) to 'explode out' of the black hole by overcoming the gravity? Perhaps the protons or electros would repel each other enough to do so.

 

Your last comment is very interesting. Instead of a 'big bang' we have a 'big rush'. That would explain most (if not all - I don't know all of the eveidence there is) of the evidence for the big bang.

[flexinglarge]

I have a thought, which probably has already been proposed, could it be a possiblilty, which i am sure it could, for potentiality exists everywhere, that the center of our universe is a super massive black hole from which everything originates? Could it be that the beginning of time/space and all contained within, was formed at the point where mass/density of the black hole (singularity) could not contain all said energy and mass, which ergo big bang theory, spewing forth our universe which we exist, expanding only as efficiently as space allows, and with a definite end, contracting back to the origin for yet another cycle of (universe recreation)? Of course for infinity.

[Deepwater6]

If I have understood you're post correctly you are saying that the expanding universe continues to expand due to the mass and energy being pulled into it from a black hole. I have thought about this myself. What I can't understand though is it's rate of expansion continues to grow. For it to grow like that would it indicate that the black hole is growing larger pulling more in?

 

 

 

I have a thought, which probably has already been proposed, could it be a possiblilty, which i am sure it could, for potentiality exists everywhere, that the center of our universe is a super massive black hole from which everything originates? Could it be that the beginning of time/space and all contained within, was formed at the point where mass/density of the black hole (singularity) could not contain all said energy and mass, which ergo big bang theory, spewing forth our universe which we exist, expanding only as efficiently as space allows, and with a definite end, contracting back to the origin for yet another cycle of (universe recreation)? Of course for infinity.

[CraigD]

Simple black hole math results and neutron star and black hole trivia

Oops – I forgot about this thread! :( Thanks, JAT and Deepwater, for giving it a bump, and a belated welcome to hypography!

 

But wouldn't there be a point at which the matter in the black hole could theoretically have enough elastic energy (or something similar) to 'explode out' of the black hole by overcoming the gravity?

According to the theory we think of as best describing them, GR, nothing, no matter how energetic, can emerge from within the event horizon of a black hole. There are several ways to explain this, a good one being that doing so involves acquiring an infinite amount of GPE, which would require an infinite amount of some kind of energy, which you can’t have.

 

I think it’s good to avoid thinking of black holes as necessarily very dense. Some pretty simple geometry and arithmetic can be used to show that, at about 130,000,000 solar masses, the average density of the stuff within the event horizon of a non-rotating black hole is about 1000 kg/m³, the same as the density of water. For a typical galaxy (about 10⁴² kg), the density is about 0.0007 kg/m³, less than 1/1000th that of air, and about the same as the average density of a sphere centered on the Sun, extending to somewhere between Earth and Mars.

 

This doesn’t mean that all of the matter in a naturally occurring suppermassive black hole isn’t compressed into something very dense (GR predicts is compressed into an infinitely dense, zero-volume singularity, but we’re pretty sure that can’t actually happen, and that GR’s not the right theory to use inside black holes), but it does mean that large volumes of supermassive black hole insides must be essentially vacuum.

 

Perhaps the protons or electros would repel each other enough to do so.

Protons and electrons have opposite charge, so attract, not repel, one another.

 

For black-hole stuff, this likely doesn’t matter. Atomic and astro-physics is pretty confident in predicting that, as a body approaches star-size black-hole mass and density, protons and electrons undergo inverse beta decay to become neutrons, becoming, in a process known as electron degeneracy, a sort of single gigantic, lumpy atomic nucleus made of nothing but neutrons, know as neutronium.

 

It’s possible for a body to get this compressed, yet not be massive enough to be a black hole. Such a body is a neutron star. Though we’ve never directly seen the surface of one in a telescope, or poked one with a probe, we’re pretty certain observed objects such as pulsars are neutron stars.

 

If I had to pick a single bit of “black hole trivia” that everyone should know and never forget, it’s that, other than their quality of having their Schwartzchild radius be bigger than their physical radius, and not giving off much light, star-size black holes aren’t much different than stars. A star of mass M exerts exactly the same gravitational attraction on a body at distance R as a black hole of mass M at a distance of R. Though they make lousy neighbors for fragile-celled planet dwellers like us, tending to surround themselves with big, hot accretion disks that spew x-rays and other nasty radiation, there’s no reason that, assuming they survive their stars change-of-life passage into black hole-hood, a black hole can’t have planets and the other features of a normal star. Quite a number of black holes, including the famous Cygnus X1, share their neighborhood with an ordinary companion star - the reason Cygnus X1 is so famous is that it was one of the first likely black holes spotted, because it gives off so much and such peculiar radiation due to its constant supply of matter from its neighbor star.