All kinds of extreme nuclear explosions

Hi,
you surely remember Nagasaki and Hiroshima, probably not personally though at least from school.

Before and after at the place of explosion in Nagasaki

The amount of energy released by Little Boy (that is the bomb), was 63 tera Joules.

This is the same amount of  energy that would be released by annihilation 0.35 grams of any matter and antimatter.

This could sound like a small value but look again on the picture above, such an energy is able to wipe out entire city.

Now just take a moment to think how disastrous would be if we were able to create actual antimatter bombs. Remember your cat from last post? It weights roughly 4.5 kilograms. Now imagine that it would collide with the cat of your neighbor (accidentaly your neighbor somehow manages to hold antimatter cat). The amount of energy released would be about 1/100 of the energy used by USA every year.

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Those are the cats that are flying towards each other creating huge explosion

This does not sound so impressive but now you must realise that the explosion would be equivalent to almost 26 Little Boys.

The graph that shows the power of explosions, Hiroshima is pretty small compared to largest nuclear test ever: Tzar Bomb.

Now there were other kinds of tests and the most violent, by SSSR was Tzar bomb.

 

Tzar bomb had the energy of 210 peta joules.

 

This is a lot. It had weight of 27,000 kilograms and its type was thermonuclear weapon.

It is estimated that the energy is 10 times the energy combined of all explosives in WWII.
It was actually planed to have it two times stronger but they realised that the airplane would not have a time to escape.

The fireball from the explosion did not touch a ground because of the shockwave.

The mushroom cloud was even 95 kilometers tall and at base 40 kilometers wide.

It was so powerful that it was possible to get 3rd level burns even 100 kilometers from the site of explosion.

Tsar photo11.jpg

Dragallur

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Are you going to explode in vacuum?

Hi,
when I first saw this question on SciShow, I was like, hmm OK, this is interesting.. maybe you will freeze or what?
Just ask anybody, anybody who does not study physics and they will say to you that person exposed to vacuum of space is going either to: explode, freeze or their blood is going to boil. Those people are right in only one thing and that is that you will die horribly. And that is why I like this question so much, it is full of misconceptions!


So last time I talked about vacuum and how it is not really empty but that is not important right now. We will talk about vacuum of interstellar space. This space is not absolute vacuum, there are still hydrogen and other atoms flying around but not much of them.

So lets get to first answer that somebody would maybe say. Person is going to explode because the the pressure in vacuum wants to equalize so you are going to be ripped apart in drastic death. I mean, imagine the person ripped to pieces and all the blood floating in very small balls all around, this simply too awesome.

So why wont it happen? Well the force of the vacuum is not strong enough. You would probably feel some pain as your tissue would be stretched a little bit, but humans are not so fragile so they wont explode.

At first I thought that person would freeze.. but watch out this is probably the greatest misconception about temperature.
What is that space between two parts of window? Well you have probably heard that it is very good vacuum. Why? Well you need to keep your house isolated so what happens is that the heat or cold air from outside will only not get inside because there is nothing that could transfer this heat!

Temperature is only the movement of particles and when there is none there is none temperature. This means that you would be perfectly isolated and that means to feel pretty warm!

Also people say that your blood would boil. Well first, why does not it boil when you are in space suit? Because the pressure inside space suit is separated from the pressure outside. This is also true for your blood circuit, it is separated from the vacuum of space. BUT what is not separated is your saliva in your mouth which would boil right away.
When we are talking about what is closed system and what is not, well your lungs are connected to the outside world, all of their oxygen would get out of you immediately. Whole circuit of blood would run “backwards” because that blood running through your lungs would lose all the rest of the oxygen instead of receiving it.

So the thing which would kill you would be the lack of oxygen. You would pass out in 15 seconds and in two minutes you would be dead.
Meanwhile you would get awesome amount of radiation and really cool sunburns which would cause probably even better cancer.

Once during some test for astronaut, the space suit was not working properly and the tester was exposed to artificial vacuum. He passed out, and his last thought was that his saliva was actually boiling, that must be very strange!

Dragallur

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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

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