- 4056 - UNIVERSE - is it a blackhole? Is it collapsing into one? The expansion of the universe in its early days prevented all the matter from collapsing. If our universe was born with way too much matter it could have slowed down that expansion. But the fact is that there wasn't enough matter to do so, and the expansion of the universe was able to dilute the material of the cosmos enough so that it could never collapse again.
---------------------------- 4056 - UNIVERSE - is it a blackhole
- Why didn't the Big Bang
collapse in a giant black hole? The black
hole is the crushed remnant of a massive star that exploded as a supernova. The
surviving core is several times the mass of our Sun. The black hole traps light
because of its intense gravitational field. The black hole distorts the space
around it, which warps images of background stars lined up almost directly
behind it.
-
- This gravitational
"lensing" effect offers the only telltale evidence for the existence
of lone black holes wandering our galaxy, of which there may be a population of
100 million. The Hubble Space Telescope goes hunting for these black holes by
looking for distortion in starlight as the black holes drift in front of
background stars.
-
- Despite the enormous
densities, the early universe didn't collapse into a black hole because, simply
put, there was nothing to collapse into.
-
- It's relatively
straightforward to make black hole if you are persistent enough. All you need
to do is apply enough pressure and keep squeezing something down to incredibly
small volumes. At some point below a critical threshold the gravitational force
becomes so strong that it overwhelms any other force of nature, creating a
black hole.
-
- If we were to take you
and squeeze you down to about the size of an atomic nucleus, you would become a
black hole with the width of an atomic nucleus and the mass of a human being.
We could repeat the process with the Earth, creating an Earth-mass black hole
about the size of a bean.
-
- Black holes are
incredibly common throughout the universe. They occur naturally when massive
stars die. They have so much mass crushing in at the core that gravity can just
keep pulling.
-
- The key to making black
holes is density. You need an incredibly high density to trigger a sufficient
amount of gravitational force. And while the universe in its present day is not
dense at all, with an average density of about one hydrogen atom per cubic
meter, and its early days things were much different.
-
- Billions of years ago
our universe was a lot smaller than it is today, and that means its density was
much higher. So it's natural to wonder why the universe didn't collapse
directly into a black hole.
-
- But to make a black
hole it's not just a matter of density, it's a matter of “density difference”.
In order to feel the gravitational force you need a difference in density from
place to place. If the amount of matter is smooth throughout a volume and there
are no differences, there will be no net gravitational force pulling in any
direction.
-
- In order to make a
black hole you have to take a bunch of matter and squeeze it down into a very
small volume, and crucially leave a bunch of empty space surrounding it. That
way the gravitational force can act and a black hole can form.
-
- Even though the early
universe was incredibly dense, it was also incredibly uniform. The average
density throughout the universe was the same from place to place. There weren't
enough differences to trigger the formation of black holes.
-
- But what about the entire
universe itself? Surely with all that matter in the universe it could have
halted the big bang in its tracks and collapsed everything down back into
singularity. This wouldn't strictly be the formation of a black hole, however.
Black holes are points of infinite density sitting inside of space. The
singularity at the big bang was an infinite concentration of space itself.
-
- But either way, this
didn't happen because the universe was also dynamic in its early days. It was
evolving. It was changing. And most importantly it was expanding. The expansion
of the universe in its early days prevented all the matter from collapsing.
-
- If our universe was
born with way too much matter it could have slowed down that expansion. But the
fact is that there wasn't enough matter to do so, and the expansion of the
universe was able to dilute the material of the cosmos enough so that it could
never collapse again.
-
-
June 16, 2023 UNIVERSE - is
it a blackhole? 4056
------------------------------------------------------------------------------------------
-------- Comments
appreciated and Pass it on to whomever is interested. ---
--- Some reviews are
at: -------------- http://jdetrick.blogspot.com -----
-- email feedback,
corrections, request for copies or Index of all reviews
--- to: ------
jamesdetrick@comcast.net
------ “Jim Detrick” -----------
--------------------- ---
Friday, June 16, 2023
---------------------------------
-
No comments:
Post a Comment