I've been philosophizing a lot about the theories of relativity a lot lately, so i thought it would be a good idea to post my thoughts in a forum like this to see if i'm understanding it right. Or maybe not understandig it, but accepting it right

The way i understand einsteins relativity-theory, is that he stated that everything is relative, or everything is in motion and everything is moving compared to eachother, which obviously makes it difficult to determine speed and direction observed objects amongst others. "Speed compared to what? Oh you mean compared to this other thing which is also moving?" And again the same with direction.
He basically states that whenever we carry out an experiment and observe something, the result we get is relative to the conditions surrounding the experiment.
And then he stated that this goes for everything in the universe, EXCEPT for the speed of light in vacuum. The speed of light in vacuum is always constant, at approximately 300.000 km/sec. And this is where it starts to make no sense. And the fact that the speed of light is always constant in vacuum is what made his theory so revolutionary.

Consider this:
A guy is floating around somewhere in space. For the sake of the example, let's say that he has zero velocity compared to the center of the universe. A spaceship flies past him at half the speed of light, or about 150.000 km/sec. The guy floating in space shines his flashlight after the spaceship, and he observes that the light from his flashlight is leaving him with 300.000 km/sec. When the light passes the spaceship, the astronauts can observe that it passes them with 300.000 km/sec. Now this makes no sense... Unless their space-time bends proportionally to the speed of light, and one second for the guys in the spaceship is actually two seconds for the guy hanging in space with zero velocity.
However when the guys in the spaceship measures the frequency of the lightwaves, the distance between the clock's should increase. That's the only way it makes sense in my head at least. Like when you hear the sirens on an ambulance and you can hear the frequency becomes longer when it passes you, and it's tone sort of bends down when it's driving away form you. Now if it is true the the frequencies change compares to the observers velocity, wouldn't that make it pretty impossible to determine what kind of wavelength that light we observe originally had. I mean the wavelengths of light emitted from the sun probaly wouldn't be affected when observed form earth since the solar system sort of moves around in space as a single unit, and our distance to the sun is ruffly always the same. But when observing objects far away in space that has different velocity and direction compared to us, wouldn't it mean that we can't really determine the original wavelengths of the light emitted. Or does lengthcompression due to velocity corrigate for the wavelength of the light so that it sort of remains constant.

And my final thought is:
Isn't all this sort of against newtons first or second law that states That energy can't be created nor destroyed, and the amount of energy in a closed system like the universe remains the same. Cause different light-frequencies carry different levels of energy. But then again spacetime maybe accounts for this, and makes it all okay again

Last edited by mortenrobinson (2008-04-05 17:31:56)