Putting the “bang” in the Big Bang - MIT theoreticians propose the "reheating" period

[gary]

In a press release today (http://news.mit.edu/2019/putting-bang-in-big-bang-1025)by MIT, Jennifer Chu describes theoretical
work being done there to try and bridge the gap between the brief
inflationary period and the Big Bang itself.

The MIT theoreticians are referring to this intermediate stage as the
“reheating” period that kickstarted the Big Bang in the universe's first
few fractions of a second. They have performed computer simulations.





Full press release here :-
http://news.mit.edu/2019/putting-bang-in-big-bang-1025

[xelasnave]

Thanks Garry I love big bang stuff...
I heard yesterday yesterday via YouTube a qualified guy say the universe was 250 times larger than the observable universe which is approx 95 billion light years diameter...so I don't know if he means 250 times greater diameter or 250 times as much stuff.
This is such a lot of stuff. I can not see how all of it could fit in a shoe box. .any views?
Alex

[morls]

This may be a silly question, but does the Big Bang theory postulate that all the matter that is - and ever will be - in the universe has been in existence since the very beginning, albeit in different states of being?

[gary]

Hi Stephen,

Indeed, the Big Bang theory postulates that all matter originated at that
instant, starting from a singularity.

One must also be mindful of the matter/energy equivalence through
E=mc2. That is seen most dramatically when stars fuse matter, some
of which gets converted into energy.

It is believed that less than 400,000 years after the Big Bang, the first
hydrogen and helium atoms formed when electrons started to become
bound in orbits to nuclei.

But the accounting doesn't quite add up. Approximately 26% of all
matter is believed to consist of so-called "dark-matter" and 70% of all
energy to be so-called "dark-energy".

The "dark" here meaning nobody really knows what it is.

So the visible universe is possibly only 4% of the total universe.

The puzzle over what "dark matter" and "dark energy" are is one of
the deepest mysteries in science today. Suffice to say, many scientists,
engineers and technicians are actively involved in a competition
to be the one that makes the breakthrough discovery.

When you consider how much of the puzzle we have worked out since
Edwin Hubble in 1923 where before that it was believed the Milky Way
was all there was, then we have come along way in our understanding
in a short amount of time.

[morls]

Thanks Gary,
While I find that I can understand basic principles of the Big Bang theory, I'm a long way from fully comprehending the idea that all matter originated in that one instant.

At the moment I'm grappling with a notion, which may be mistaken, that space is created through expansion, rather than matter expanding into empty space. It is hard to understand there is no "outside" into which space expands. This metaphor probably doesn't make sense...

[gary]

Hi Stephen,

Indeed space itself was created but don't worry too much, nobody can
visualise what that must have been like, especially if you try and visualise
it looking at the singularity from the "outside". :)