parkinho

I am also of the opinion that Pluto should be downgraded from its status as a planet, and a placed under the title of 'Kuiper Belt Object' along with Sedna, 2003UB313, etc.

Yeah, cheers. I had my wires crossed/not thinking properly.

'two observers having a relative speed greater than c' but this cannot happen. Or have I misunderstood the point that you were making?

Have you worked out the answer yet Sarah? I have just worked it out roughly to be approx 35600km. Good luck with your exam Andy

Yes, visible light (along with gamma,x-rays, microwaves etc) is a small part of the electromagnetic (EM) spectrum and they travel at the speed of light, which in a vacuum is 300,000,000 m/s. The colour of light photon depends on its energy, which is dependent on frequency (E = hf where h is Planck's constant). And of course, the higher the frequency, the shorter the wavelength (and vice versa)

Hi guys, Could someone possibly tell me what is the first image that an alien race would receive? I'm sure that I read somewhere it is Adolf Hitler at the 1936 Olympics in Munich. Cheers