Various fields for dummies!

Hi,
fields? Well yes, this is probably the last post before I will write about Higgs boson. Today you will learn that everything is made up of fields and that particle is just a special vibration.


Take for example magnet, it is something totally special if you think about it. Not that it sticks to stuff but that you can feel how it wants to stick without actually touching anything, just through EMPTY SPACE!

Magnet has his magnetic field all around, that is why we can feel it from some distance and the strength decreases with distance increasing.

On the picture above you can see lines of force around magnet.
This is electromagnetism and now we know that there is electromagnetic field around all the stuff that have charge. We know that we can magnetize needle using electric current.

This field is not only around magnets but also around all things that have mass, this is called gravitational field and even that it does not sound very exciting to us, in Newtonian age it was very cool when Newton found out that there is similarity between apple falling on his head and Moon orbiting Earth!

What happens when you start to rapidly move with source of electromagnetic field? Well you create waves. If you do it well enough such waves will create light! This light then comes to you in quantum! If you do it more rapidly you will get gamma rays and if you do it less rapidly you will get radio waves. This is just a vibration of field.

Or when you take radioactive decay. There is neutron which somehow changes itself into proton, electron and antineutrino. This is just a change of vibration in various fields.

Now there are 4 fields if I do not count Higgs field. What physicists want to achieve is the prove that all those fields are just one field and everything is just a various vibration of it, creating the effect of gravity, electromagnetism and so on. This would be the Theory of Everything.

Dragallur

Advertisements

The riddle of DARK ENERGY!

Hi,
today I will write about dark energy since last time I briefly covered the dark matter. The dark energy is even more unknown than the dark matter, let’s see why.


As I said before, there is about 70% of dark energy in the Universe of all the energy that there is, rest belongs to dark matter and tiny bit to normal matter.

Dark energy has to do a lot with expansion of Universe which was find out last century by Edwin Hubble. He found out that the Universe is expanding and right now we even know that the rate of expanding even increases (The Big Rip scenario).

Why? Because there is something called dark energy and we know that it works kind of like “anti-gravity” this could be misleading since the gravity is still there so it is also said that it has “negative” pressure.

Dark energy is everywhere at the same amount and as the space is expanding there is more of it created. This does not violate conservation of energy since the force of gravity decreases at the same time with the distance increasing. I guess that this is why the expansion increases.

There are four theories which I found about the dark energy, the first one is that dark energy is not a thing but rather property of empty space and empty space is expanding and as the expansion increases so does the rate.

Second idea is the idea of cosmological constant which was made by Einstein. At the start it was constant which would be zero so that space would be static but as Hubble found out Universe is expanding so the cosmological constant, which is kind of property of space must be higher than zero. Now lot of cosmologists are trying to measure this constant, this is a big problem since when we try to calculate it, it goes with orders of magnitude away from what we can observe and it is simply wrong.

Or also virtual particles popping in and out of existence in space could give energy to this dark energy.

Simply we do not know much about it but we know that it must exist in some kind of form.

Dragallur

 

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

1st picture
2nd picture

 

Taking closer look on, NOTHING!

Hi,
in this post I want to look on literal nothingness, vacuum, empty space.
And why are neutron stars so freaking dense.


When you put your hands as far away from the other one and imagine that this is the volume of atom the nucleus is going to be thinner than the diameter of human hair.. well yes, that escalated quickly. And I am not even talking about electrons which are much smaller than protons and neutrons.

This simply means that you are, and everything you know, is mostly made up of empty space.

Now for the neutron stars.
Neutron stars are collapsed massive stars. They are extremely small and dense at the same time and the gravity of all the stuff keeps this stable.
Wow, neutron star is pretty scary when you take that their diameter ranges from 10-20 kilometers and at the same time they have 1.35 to 2.1 of Solar mass. The first picture corresponds to this, so if you would compress all humanity to size of sugar cube it would be as dense as neutron star. So in neutron star there is not much of empty space.

That is all for neutron stars but let me return to the empty space and vacuum.

Vacuum is extremely important, while I don’t want to list all technology using it, let me say that for example simple straw is working because of vacuum.
While you are not making the best vacuum ever, when drinking your juice from straw, you are lowering the pressure so the juice runs up. If you would lower the pressure a lot like in space this effect would be much stronger (you would not explode).

There is actually scale on Wikipedia about the levels of vacuum. OK now lets assume that you would be able to suck out all of the air and stuff inside closed box.
Is there going to be something?

Yes, it may sound strange but there is lot of stuff, and this stuff likes to change a lot.

Lets introduce you virtual particles!
OK, they are real kind of, at least it is known that they really exist. They have to do a lot with quantum theories like quantum field theory.. I do not understand any of it but that is not really important right now.

Virtual particles are particles that are popping in and out of existence all the time. In this kind of way they should be in pairs which then both disappear in nearly NO time. I read that since they are so virtual and may not carry any energy or momentum they may even travel faster than light or travel in time (this is questionable, as you will see (source Wikipedia)). Those particles are made in pair, one of them is anti particle so they then collide and annihilate.
For example there are virtual photons that actually do any kind of electromagnetic radiation, so photons are called force carriers of e. m. radiation. I already wrote about this earlier..

OK, I know that there must be something more to it since at the same time SOME virtual particles can travel faster than light as Wikipedia says, while force can not be transferred faster than the speed of light.

So there is all the stuff popping in and out of existence which is constantly annihilating. But when this happens on the edge of black hole when one particle is inside the event horizon and the other one outside, the one outside does not annihilate and it pops into existence and escapes the black holes gravity. Since conversation of mass/energy this must have taken something from the black hole. This really happens in what is called Hawking radiation, when eventually black hole can evaporate!
To watch something more about vacuum, check this video by Veritasium where he is talking about quantum fluctuations.

Dragallur

1st picture
2nd picture