How it started, featuring Big Bang!

Hi,
when you read the title of this post it is pretty clear that I am going to write about Big Bang, I already wrote about the ends of the Universe but it feels as lot of people are interested in the beginning and there are some misconceptions.
For example even the title is little bit wrong since you could assume from it that Big Bang was the start of everything..


So I will try to explain Big Bang and what happened right after and I want to start with first big misconception.
People think that Big Bang was explosion, nope it was not. It is thought that Universe expanded into space but actually Universe is already everything and it kind of expands into itself, if it makes sense.

BigBangIsExpansionOn the picture above you can see the example of expansion where space expanded not the things inside but the fabric itself. The space in the grid increased while nothing happened to the objects except that they are further apart. This is what is happening all the time and even if the Universe was infinite it could get bigger, kind of, because everything is going away from the rest of the stuff and NOTHING can be the center of the Universe. There was no explosion.
For the rest of the post I will follow the picture on the left.

On the bottom of the picture is the start of the big bang. This is outside of the graph because we are not able to investigate it using the laws we know now. This is until Planck time passed (10^-43 seconds). After Planck epoch which is big unknown, the time of grand unification came. This is time with extremely high energies involved and it is assumed that 3 fundamental forces are working as one at this time: electromagnetism, weak and strong nuclear force. This is extremely important but we are not able to reach such energies even in particle accelerators while it could help us a lot with Theory of Everything.

Few really really short moment later strong force separated and started to work alone. This took some really long time before all the forces separated to the state we know today. This is one picosecond after big bang. Then quarks became grouping together into hadrons. Those are particles with zero “color” charge like neutron or proton.
Some time later finally deuterium is created and through big bang nucleosynthesis some heavier elements like lithium, beryllium and helium too.

Then it takes really a long time before everything calms down so that first stars and then galaxies form.

Some time I will probably return to background radiation.

At the beginning I said that you can not really say that big bang was the start of everything since there are some theories like big bounce.

Dragallur

1st picture
2nd picture

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What could happen to our Universe: Big Bounce

Hi,
with little break from Solar System I am returning to last post about end of our Universe. This time it is very optimistic, but we will die anyway..

Right now the Universe is expanding, it is expanding in high speeds but this theory is assuming that this process due to decreased amount of dark energy reverses at one point and everything will start to shrink back. This would heat Universe over time. About 100,000 years before big crunch space would be hotter than surface of stars which would make them cooked from outside (FUN).

Then all matter would fall into black holes and all of those black holes would fall into each other so that final singularity would be created.

Well then it could start all over again, big bang, zero expansion and big crunch. This scenario also assumes that Universe is going through infinite cycles of banging and crunching. While this is most optimistic, in the new Universe would be nothing from the one before.
Measuring of expansion of Universe does not give much points to big crunch because now it seams that expansion is speeding up. Scientists are not yet able to know why is this happening Big Bounce is still an option.

Dragallur

PS: I just lost the game… Here is post about heat death. And here about big rip.

What is the life cycle of stars?

Hi!
Somehow I wanted to write something from universe… not really I am still sitting in my hometown so here it is:

Well, stars (as our Sun) DO have beginning and end as you probably heard already. It can have different length.
First of all there have to be material. I mean lot of material because as you know our sun is huge. (Sun is bigger that 90% of stars)
This material comes from other stars that are dead now and theirs material probably came up from Big bang.
There are extremely large clouds that are called Molecular clouds. In them is lot of stuff and mostly H2.
If there is enough stuff at one place (it is really dense) it can make up planet which is either stony or made from gas.
If there is enough stuff it will make even larger gas planet than Jupiter or Saturn.
At that point all of this H2 will be pulled toward the center with magnificent force. That will create heat because atoms will be brushing against each other. If there is enough heat termonuclear reaction will occur which will normalize that pull of gravity and whooo! we have new born star!
Termonuclear reaction will change Hydrogen to Helium. Helium is heavier so it will go toward center and just a little bit of Hydrogen will be left on the edges. If the star is enough heavy it will start to change Helium to Carbon or Oxygen (I think). It will continue with couple of rounds until there in the middle is Lead (Pb). Than it will never be able to go forward and the life cycle will kind of end. Few more termonuclear reactions will occur (That is called red giant because it will greatly gain volume and the it will lose it) but then gravitation will win and if that star was small (even like our Sun) White Dwarf will be the END.
White dwarf is only really dense and hot piece of stuff.
If it was heavier.
Neutron star (made of only neutrons) will be the next stage. It extremely dense thing with tremendous gravitational field.
The last thing which can happen is Black hole, you can read about them in one of my first posts, they are absolutely awesome!

Dragallur
PS: if white dwarf gains again enough mass because of some stuff from space it can heavily explode into Supernova