Schwarzschild radius

I know this title seems that my post will be complicated but actually it is pretty easy.

I want to return to my favourite topic: Black holes, and their size.
You probably know that inside black hole is singularity and that the edge is called event horizon. Its size is different from one black hole to another and we can use Schwarzschild  radius (SR) to count it.
Schwarzschild radius is area from which light could not escape if you pressed this mass to area of sphere with Schwarzschild radius.
Its equation is:
r=2Gm/c^2 where r is radius, G is gravitational constant, m is mass of object, c is speed of light.
Earth´s SR is 9mm and Sun´s is 3km and if you would compress mass of observable Universe you would have SR of 13,7 billions of light years and super massive black hole in the middle of Milky way has Schwarzshild radius 7,8 millions of km which is also how big is its event horizon.



1) Thinking, Fast and Slow: Two systems

Hello there!
I am now reading really amazing book which is called Thinking, fast and slow. It is by Daniel Kahneman who has got nobel prize for economy. It is absolutely amazing so when I want to read I am not sure if I should rather read Game of Thrones or this one. Well, It is so good that I will even write what I learned from it.

It is about thinking: People think in two different ways using two different systems: 1 and 2.
When you are using system 1 you are acting without you even noticing.
But using system 2 you are probably solving some more serious problem and your mind is awake.
System 1 is in use always, he is really good in telling you if something is going on, what are people around you doing and it can alert system 2. example, when you look on the picture your system 1 does many things without need of energy. You see that this person is angry on someone and it is probably saying something bad (I am nearly citating the book). This is what your brain does almost always and this way is prejudice also created so system 2 (you) should check decisions of system 1. Problem is that system 2 is usually lazy.
When it comes to using of system 2 you will use it when I give you this question: How much is 17×28? You probably needed to stop on a while because system 1 realised that he does not know, only thing he can say is that it is larger than 200 and smaller than 800. Then system 2 starts to count it.
Many physical things will happen to you like sweeting or higher pulse. If you have good working memory it wont take you a long time to do it from head, it  is 476.
Well this was just a start so maybe next time I will continue.


I had little pause but now I am coming back.
Today I want to write something about dwarfs because I found them little confusing.
We are talking about dwarfs in Universe not Tyrion.. there are six kinds:

  1. Brown dwarf

    Brown dwarf is the only one which is not star. It is actually extremely big planet which almost made it for the size of star. This term is used because red dwarfs already existed.
    Scientist are not really sure when it comes  to the difference of planet and brown dwarf. Jupiter would have to be more than 50x larger to be brown dwarf.
  2. Red dwarf

    Red dwarfs are “cool” stars. For example Proxima Centauri, the closest star is red dwarf. Their mass has to be about 0.08 of Sun to 0.5 of Sun´s mass. Red dwarfs are extremely common in Milky way as most of stars are smaller than Sun. That picture shows red dwarf and it would be more orange if showed from smaller distance.
  3. Yellow dwarfYellow dwarf is not really a dwarf. It is star which is about the same size like our Sun. Its temperature on the “top” is about 5000 to 6000 K.
  4. Blue dwarfBlue dwarfs are kind of related to red dwarfs because they are just a stage in their live. When red dwarf uses almost all of its hydrogen it will need to equalize with gravity and for that he uses temperature which rises and from red color it will shine in blue. This stage is only hypothetical because red dwarfs lifetime is really long and this could not yet happen.
  5. White dwarfWhite dwarfs are stage of all stars which wont make it to neutron stars or black holes. They are about the size of earth but much denser. From white dwarfs supernovas can explode.
  6. Black dwarfBlack dwarfs are only hypothetical but it is almost sure that they will happen when time comes. They are the next stage of white dwarfs. Black dwarf should not shine anymore because it is cool. They should be also really hard to detect because of their black color.


3) Particles: Quarks

I have been writing about quarks a lot so now I would like to shortly summarize what they are.
Quarks have been discovered when scientists saw that paths of particles traveling close to neutron are distorted by some weak electromagnetic field. Then they discovered that neutron is neutral but it contains particles which are not neutral: quarks.

If I told you that protons and neutrons are only made up of three up and down quarks  you could easily figure out what is inside them. Proton´s charge is +1 which means there has to be 2 ups and 1 down because UP(charge)=+2/3 DOWN(charge)=-1/3 === 2*2/3+(-1/3)=+1. While neutron is made up of two downs and one up which equals to 0.
As you can see from the table there are six types (flavors) of quarks. I talked only about two of them because they are much more common then charm, strange, top and bottom. The reason why those four are less common is that they are extremely heavy compared to up and down quarks and they will decay into up and downs. Up and downs can not decay to anything which makes them stable. Even then it is thought that proton (uud) can decay.. I talked about it earlier so you can check my other posts.

Flavor is one attribute but there is another. I mentioned it in post about strong interaction and it is color of quarks. There are three “colors”: RGB — red, green and blue and antired, antigreen and antiblue.Three colored balls (symbolizing quarks) connected pairwise by springs (symbolizing gluons), all inside a gray circle (symbolizing a proton). The colors of the balls are red, green, and blue, to parallel each quark's color charge. The red and blue balls are labeled Those colors always have to add up to white color. There are lot of combinations which can do this – RGB, antiRantiGantiB, blue and antiblue, red and anti red… and many others

It would be far too easy without gluons which are holding quarks together. are usually drawed as a short string between quarks. The thing that they do is color changing. They do it at two points: when they enter and when they leave quark. A green and a magenta (
There is hypothetical astronomical object called Quark star which should be made up of free quarks. Also it is thought that right after big bang there was state of matter in the Universe called quark-gluon plasma… soup of free quarks and gluons. We are not yet able to create this because it probably needs extremely high temperatures.
On the left is a picture which compares mass of quarks. On the botom you can see grey proton and really small, red electron. Top quark is the largest one.

Particles which are made up of quarks are sorted into different groups: mesons and baryons you can see on the picture what they can look like and how colors add up to white.