theory of relativity

Spooky action at a distance

Hi,
maybe you have already heard it.

“spukhafte Fernwirkung” or “spooky action at a distance” – Albert Einstein

what is it? Are we able to transmit information faster than light using it?

Spooky action at a distance or also quantum entanglement. This is very famous phenomenon which seems to allow information to travel faster than light, luckily not, otherwise we would have to throw all our physical theories to trash (or maybe it would benefit, who knows).

Particles have spin as I have shown countless times in posts about standard model or about particles and so on. They have also other properties which has to do with quantum entanglement.

What experiments shown was that when independently measure two photons for example the results about their attributes are correlated. This is indeed spooky because it does not matter how far away those particles are but always the result will somewhat be similar.

This cartoon helps explain the idea of "entangled particles."

The picture above from NASA page well explains how this works. The people there are detectors called superconducting nanowire single photon detectors which are cooled to be superconductive and when photon hits the wire it changes the resistance in the wire to some higher value so you can record the event.

Why does not this break the rules of speed of light? Because there is actually no data transmitted. You can not use it to communicate since the results are random anyway. And when you know your result you also know the result anywhere in the Universe, that does not matter because it was random.

I will just repeat: you need pair of entangled particles, for example laser beam can create photons that when they go through crystal and they split, they become entangled, measuring one particle will influence the other.

Einstein thought that this is because the particles contain what is called “hidden information”. That when they are created at one point in the crystal from the laser beam for example, that they make their “secret plans” on how their spin will work out when they are measured, which would not need any faster than light travel. In this video, Derek Müller shows the experiment of Bell that shows that there is no “hidden information” and how the measurements work, because what you can do is to measure the spin of particle in various angles which changes the probability of the particle to have that kind of spin.

Dragallur

 

 

Red shift once more

Hi,
so last time I was writing about Doppler`s effect and I was using normal Doppler`s effect but actually I forgot something very important and those are relativistic speeds.

Relativistic speed is the speed when Newtonian physics is no longer able to accurately predict what is going to happen. This can happen from 1 to 10% of speed of light. This border is hard to define since it is hard to define when Newtonian physics is not enough accurate.

On the left you can see graph of increasing mass when you increase speed.

That is one of many relativistic effect, this also means that when you are walking you are heavier. Also another effect is time dilation for example.

Time dilation is the problem with red shift in Universe. You can not just use equations like I used before but you need to use special relativity with time dilation, since the thing is speeding away from you and the time runs differently for you and it.
z + 1 = \frac{\lambda_o}{\lambda_e} = \sqrt{\frac{1+v/c}{1-v/c}}This equation is the right one, more accurate for huge speeds with which you will be in astronomy probably dealing with.

Lambdas are the wave lengths of the one you are observing and the real one of the object. V is velocity and c speed of light, z is the red shift.

So I checked with one problem which I found on the internet. It was about quasar far away which is moving in high speeds. The red shift is 0.158.

So i used this calculator to find out what is v/c which was 0.14656. With this I found out what is the speed which was 43,695 km/s. Then I put it in the equation above and the red shift was about 0.15777 (something). So I can see that I did it right and this equation is truly giving us the red shift.

Dragallur

1st picture
2nd picture is from czech wiki article about relativistic Doppler effect

 

Dimensions: Short Expansion

Hi,
here it comes, here it goes, again seemingly very favorite topic about dimensions. Last time I wrote about imagining higher dimensions and how they work and that we have 3+1 dimensions. 3 are space dimensions and one time dimension. Actually I should have added that there is and option of much more dimensions. Thanks to Joseph from Rationalising The Universe reminding me of this through his post which I recommend you to read.

Fine if you read his post you know that I want to talk about dimensions that can exist in string theory.

So there are two main theories: Theory of Relativity and Quantum theory.
What we know for sure that both are wrong. This is because TOR is not able to predict stuff on small scales and QT on large scales while they are both very good on their fields.
Then there is third guy called String theory. This theory says that on very small scale fundamental particles are one dimensional strings, which mean lines and when you are looking at them “from above” they look like particles.

String theory predicts a lot of dimensions on extremely small scales (check Joseph`s post to read about gravity etc.).
There are two most important ST theories. Boson and Superstring theories. The first one predicts 26 dimensions and second 10, now choose :D.
The thing is that actually for some stuff it is much better to have more dimensions.
Since for me it is so extremely complex I can just advice you for wiki page for start.
Still String theory is just theory as are others and I am totally looking forward to Theory of Everything!
Dragallur

Eclipse, bus ride and theory of relativity

Hi guys!
It is two days since eclipse of sun.
First of all I will just remind you what eclipse is.
So, it is shadow of moon, because of its rare position between sun and you.
Imagine having lamp. It is your sun. Take your hand (moon) and move it between you and lamp. That is how eclipse works.

There few kinds of it. There is full eclipse.
This one on the left is full eclipse from year of 1999. Picture was taken in France. For full eclipse you usually need to go to some specific place which is calculated by some math quys 😀 . Because that is the only position you can change… you can not change position of sun, moon or earth but you can travel yourself.

Here on left is picture of solar eclipse. You can see that shadow of moon is not visible everywhere… only on very small spot (about 250km^2) is full shadow.
There are lots of things that have to work together if you want for example to have full solar eclipse visible from window of your house.
Because moon is 400x smaller than Sun, Sun has to be 400x further away. At same point your house has to point exactly towards sun and at the same moment moon at right distance has to orbit across your point of view when you are looking at sun.
Well that wont happen 😀 .

Because moon is slowly going away from earth and sun is gaining volume, last full solar eclipse we will be able to see will be 600,000,000 years from now.
You can see list of eclipses on wikipedia. Next total one will be March 9 2016. But it will be somewhere in pacific ocean.

Anyway, two days ago I was in bus by the time when eclipse was seenable. Luckily i was sitting in back seat from which you can see huge part of sky. Well I forgot to take some kind of black glass so I saw it for few seconds before I was too blinded, hope nothing happened to my eyes. Anyway I am looking forward to next eclipse and I hope that you guys did see it!

Eclipse was very important when Einstein wanted proof for theory of relativity. He was predicting that as huge objects bend spacetime, light will be curved if between sun and you is some object with huge gravitional field. Actually moon has too weak gravity so you cannot really see it but when you have quasar and black hole is between quasar and you, you can see that effect of bended spacetime. It is called effect of gravitational lens. http://en.wikipedia.org/wiki/Gravitational_lens On wikipedia page you can see short video of how it looks like, it is pretty amazing.

Thank you for your likes,
Dragallur