# Harmful radiation

1. Dec 8, 2004

### orange

Hey!

If one travels fast enough against it, will a regular photon of visual wavelength become harmful due to the doppler effect?

2. Dec 8, 2004

### imabug

hmm, interesting.

wonder how fast you'd have to go to blue-shift a light photon into a UV or x-ray photon. should be simple enough to calculate. The answer should tell you if it's possible or not.

3. Dec 8, 2004

### marcus

yes
ordinary sunlight is around 2 eevee and Xray is around 1000 eevee.

so you just need a speed beta which makes the doppler ratio be around 500. Here is the relativistic doppler formula, squared both sides to make it easier to write.

250000 = (1+beta)/(1-beta)

if you solve this for beta you get
beta = 249999/250001

so that is what fraction of the speed of light you would have to go
in order to boost the photon energy by a factor of 500

but well before that it would be harmful

Last edited: Dec 8, 2004
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