AstroBlonde

Once again, Einstein wins! Yep, it sure seems that way after scientists have studied the results from NASA's Fermi Gamma-Ray Space Telescope. At last week's group meeting we discussed the Fermi QG photon-lag measurements, so here's a litte info about it.

Einstein said in 1905, in his theory of relativity, that light has a constant speed and it was independent of its frequency, or how you're moving. Light has amazing properties and can sometimes confuse people. For example, if you travel on a, let's say a space station with a constant velocity, and you would throw a ball in the opposite direction as you're moving you would probably think it's logical that the ball will move away from you faster than if you threw it in the same direction you're moving. Right? If you throw it in the opposite direction the space station would have a velocity in one direction and the ball in the other direction. For you it would look like the ball has the velocity you threw it with, but you will also move in the other direction which makes the velocity seem even larger.

With light, that is not the case! Light will travel at the speed of light no matter how fast you're travelling or no matter the direction you send the light in. If you would travel almost the speed of light and lit a torch in the same direction you're travelling in, you will measure the velocity to the speed of light as much as if you would send it in the opposite direction. Fascinating, isn't it?! That's the reason for saying that light has a constant velocity, or speed (velocity is when you have a direction and speed is when you ignore direction).

According to theory light has the same speed for all its wavelengths, or frequencies if you prefere. Wavelength, frequency and energy is connected together: if you change wavelength, you change both frequency and energy and so on. Light has a wide range of wavelengths. Some wavelengths we see as colors where red has a longer wavelength than blue. If we go to longer wavelenths than red we get infrared, microwaves or radio. If we go to the shorter wavelength than blue we get ultraviolett, X-rays or gamma rays. So when we use the TV or radio we use light or when we use the microwave. When we're laying at the beach to get tanned our skin reacts to the UV-light and When we're at the dentist to get an X-ray we use light. The longer the wavelenths is, the less energetic the light is. Gamma rays, which has the shortest wavelengths and therefore is the most energetic, is very harmful to us.

But scientists have wondered that perhaps the different wavelengths, or frequencies, of light have different speeds. The change in speed must be really small, but could it be? One suggestion is that space has a granular structure on very small scales. That would lead to some light waves would travel faster than others. We already know that on small scales, like particle scales, we have to use quantum mechanics to understand what's going on. On that scale there are alot of statistics going on, and random events, things that seem very different from our orderly looking world. Scientists don't know how to combine these two "worlds", quantum mechanics with our Newtonian, and therefore maybe light can help us out. If different wavelengths can travel in different ways in this small granular structured space, perhaps we can find a relation between quantum mechanics and our Newtonian world.

So, NASA's Fermi Gamma-Ray Space Telescope studied gamma rays of differing energies, in other words different wavelengths and frequencies, coming from an exploding star when the universe was half its present age. For 7.3 billion years the light travelled through space and finally hit the telescope which had the timer on. It turned out that the different wavelengths do not have different speeds, so Einstein is still right! But astronomers don't give up that easily. More tests are needed, and perhaps the light needs to travel even longer distances to be able to be measured better. This is just the beginning of testing Einsteins theories and so far 1-0 for Einstein vs. scientists.

You can read more about it here
7.3 Billion Years Later, Einstein’s Theory Prevails

Personally I'm kinda hoping that they would find something weird about light so we get some hints about the connection between quantum mechanics and Newtonian physics, but at the same time I'm going to become a bit upset if they do. Light seems to be an awsome particle with alot of secrets, and it's kind of perfect in one way. If they would measure that light has different speeds at different wavelengths, that would make the photon (light) less perfect. But hey, even the Sun has spots... Even though they appeard a little bit late this time. But that's another story.

Today I've been walking back and forth to the garbage room. I never thought I had that much garbage in my appartment! I've found papers and receipts from 2004! Why have I saved them through all these years?! I threw away some clothes and shoes I never use and put all my books in a box. I realized that I must have sold off around 30-40 books this year, because all the books I have left goes into just one box. Yay! I've also spoken to a friend of mine in Sydney and he's gonna pick me up from the airport. He's so kind to me and I think he's going to be like a big brother to me over there. It's great and people are so friendly in that country!

I can't belive that I have to move away from this appartment in about two weeks! I mean, there are things everywhere! Gosh, I have so much work left to do here before leaving! Ah well, it's gonna work out in the end. It always does!