Big Bang: Escape Velocity Change from >c to <c?

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In summary, the conversation discusses the concept of a black hole and its relation to the big bang. It is mentioned that the universe has always had a nearly homogenous and isotropic mass distribution, making it unlikely that the big bang was caused by a black hole. The conversation also touches on the topic of whether the LHC can create a mini big bang and the purpose of the CERN research center. The concept of a hole in space versus the expansion of spacetime is also brought up, with questions about the size and mass of the universe and the potential for 1mm black holes to exist in the early stages of the universe.
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edpell
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If all mass of the universe was in a region 1mm in extent then was it a black hole (escape velocity greater than c)? Now 13 billion years later the universe is bigger. What is the escape velocity now? Did it change from >c to <c?
 
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The big bang is an odd phenomenon. Singularities are a problem for current physics. I don't think you can really think of the big bang having arisen out of a black hole (Current Physical laws don't seem to work at the moment of the big bang or before, only something like 10^-42 seconds afterwards). There is no escape velocity for the universe, as far as I know you can not leave the universe...
 
  • #3
edpell said:
If all mass of the universe was in a region 1mm in extent then was it a black hole (escape velocity greater than c)? Now 13 billion years later the universe is bigger. What is the escape velocity now? Did it change from >c to <c?

Since the Schwartzchild radius tells the maximum radius a given mass could have to be a black hole, we can calculate the minimum mass of a 1mm black hole.
[tex]R_{Schwarzschild}=\frac{2GM}{c^2}\approx 3km(\frac{M}{M_{sun}})[/tex]

So setting the Schwarzschild radius equal to 1mm, we get 7*10^23 kg, about a tenth the mass of the Earth.

Really, the smaller a black hole you can achieve (good luck overcoming degeneracy pressure), the less mass you need. (A massive body becomes a black hole depending on the density.)

However, there's a much more important issue here. The Schwartzchild radius describes black holes in space. The big bang was not an explosion in a background of space. The big bang involves spacetime itself expanding from a single point. The universe (which may or may not be infinite) has always had a nearly homogenous and isotropic mass distribution.

In addition, it might interest you that the big bang had excruciatingly low entropy while black holes have the highest possible amount of entropy in a given region of space.
 
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  • #4
edpell said:
If all mass of the universe was in a region 1mm in extent then was it a black hole (escape velocity greater than c)?

Fact is that just after the BigBang, matter did not exist. There was something like a soup of plasma more or less seethrough. It took "very long" for matter to form.

Therefore, you cannot think in the sense of compressing matter into a very small volume. You need to see the Big Bang as a release of energy that eventually formed elementary particles, that eventually formed nuclei, that eventually formed atoms, that eventually contracted to form the matter as we know nowadays.

Cheers
 
  • #5
Does your collective thinking believe that the LHC can create a Little, Big Bang?

If yes, then that is a lot of bucks for the bang! ... or will it answer the $4.5B question! Is the Higgs Boson the end of the question? What is the next question?

OR, if the answer is no, then 1.) another failed attempt? , or 2.) WHAT? "We came, we saw, we conquered, we left suddenly!"
 
  • #6
Bethann said:
Does your collective thinking believe that the LHC can create a Little, Big Bang?

By just taking a quick look at the CERN's website makes you realize that they are not focusing on just one particular field. The CERN is a research center open to all research team around the world.

Some of their projects, like the ATLAs has a very specific focuse, and they will use part of the beam. But other research are always welcome to apply for beam time.

Cheers
 
  • #7
Bethann, I enjoy your sense of humor "we left suddenly" :)

Fatra2, I do not think it "matters" (sorry for the pun) if the stuff is energy or matter I get the impression these are about the same as far as gravitational effects are concerned.

Jolb, your remarks about a "hole in space" versus "spacetime itself expanding" contains so many ideas I do not know where to being and many of the ideas I do not understand. I would ask when can we talk about holes in space? How big does the universe need to be? If a 1mm black hole is about a tenth the mass of the Earth then using 10^55kg as the mass of the universe we can make 1.6x10^30 black holes. If they are all packed next to each other than there was a time when the universe was about 11,000km in radius it "contained" 1.6x10^30 black holes packed cheek to jowl. How do you think about this? At what point do we move from expaning spacetime to hole in space?
 

FAQ: Big Bang: Escape Velocity Change from >c to <c?

1. What is the Big Bang theory and its relevance to escape velocity?

The Big Bang theory is a scientific explanation of the origin and development of the universe. It states that the universe began as a singularity, a point of infinite density and temperature, and has been expanding and cooling ever since. The concept of escape velocity is important in understanding the expansion of the universe, as it dictates the speed at which an object must travel to break free from the gravitational pull of another object.

2. How does the escape velocity change from >c to

The change in escape velocity from being greater than the speed of light (c) to being less than c has significant implications for the Big Bang theory. It suggests that the early universe expanded at a rate faster than the speed of light, which challenges our current understanding of the laws of physics. It also raises questions about the nature of spacetime and the possibility of other unknown forces at play.

3. What evidence supports the change in escape velocity from >c to

One of the key pieces of evidence for the change in escape velocity comes from observations of the cosmic microwave background (CMB). The CMB is the remnant radiation from the early stages of the universe and its temperature is very uniform, which suggests a period of rapid expansion. Additionally, the observed distribution of galaxies and the large-scale structure of the universe also support the idea of an initial period of inflation.

4. How does the change in escape velocity relate to the concept of the observable universe?

The observable universe refers to the portion of the universe that we can see and study, given the limitations of the speed of light and the age of the universe. The change in escape velocity from >c to

5. What are the implications of the change in escape velocity for the future of the universe?

It is difficult to predict the exact implications of the change in escape velocity for the future of the universe. However, it does suggest that the expansion of the universe may continue to accelerate, potentially leading to a "Big Rip" scenario where the universe expands at an infinite rate and eventually tears apart. It also raises questions about the fate of the universe and whether it will continue to expand or eventually collapse back in on itself.

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