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I'm not sure if the same logic applies to light and rain when comparing running/driving with a stagnant situation. See, e.g. Why does driving faster make my windshield catch more rain?

Suppose I have a car with the top down and no hat/short sleeves, will I get more sun exposure, and thus burn faster, when driving on the freeway rather than when parked?

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Alex Broadhead
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    I'm voting to close this question as off-topic because it is about the biological response to a particular stimuli and not physics. – Kyle Kanos Aug 05 '15 at 19:02
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    Raindrops fall at a few meters per second. You drive at a few tens of meters per second. The aberration of rain due to moving horizontally ten times faster than raindrops fall vertically is quite large. Light moves at 300 million meters per second. The aberration of light due to moving horizontally at 1/10,000,000 the speed of light is negligibly small. – David Hammen Aug 05 '15 at 19:05
  • Maybe OP is thinking the added component of velocity will change the angle of sunlight. OP should qualify the specific physics idea he is asking about. But the physics answer is "No." – Bill N Aug 05 '15 at 19:06
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    @KyleKanos I think this is a perfectly happy physics question. Just because it comes wrapped up in a real world application, and because that application could add complexity outside the normal domain of physics, doesn't mean we can't give this a physics perspective. For example, one might discuss the issue of whether or not the photon flux on a patch of skin changes if the car is moving, or the issue of reflected light from the car interior, etc. – DanielSank Aug 06 '15 at 17:01
  • @DanielSank: Outside of the fact that light is discussed in physics, there is no physics content to this question, it is entirely about the physiology of overexposure to sun. – Kyle Kanos Aug 06 '15 at 17:11
  • @KyleKanos I though the reference to running/driving in the rain was a pretty clear indication that OP wants to know if a moving body experiences a higher flux than a stationary one. It's an interesting question from that point of view. – DanielSank Aug 06 '15 at 17:30
  • Thanks, Daniel. I thought it was quite clear that I was wondering if the same physics applied to light as did to rain, that of projecting out a solid at an angle or similar. It appears that the consensus is that it does, and that due to the relative speeds the angle is effectively zero. The sunburn part was just a cute way of asking about 'more' light hitting me, though I suppose this is more analogous to running in the rain than water on the car's windshield. – Alex Broadhead Aug 07 '15 at 00:24
  • I tried to edited the question to more stress the difference between driving/not driving. In my opinion sunburn is just a fancy term for photon flux. I hope this does not conflict wit @AlexBroadhead intents. – Bernhard Aug 09 '15 at 09:31
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    Indeed this has nothing to do with biology or physiology. –  Aug 09 '15 at 09:43
  • you know, physicists can solve (some) biology problems without knowing biology. – Shing Aug 09 '15 at 11:59
  • Thanks for the edit, Bernhard. I had wanted to link in the rain question originally, but couldn't figure out how to. – Alex Broadhead Aug 10 '15 at 16:26

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Considering light travels at relativistic speeds much faster than you can in your car, the exposure is the same. The same logic does not apply as for rain as rain doesn't fall at relativistic speeds.

nluigi
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  • I'm not sure whether this answer is correct or not. It seems clear that since light travels much faster than my car, there will be no measurable difference in exposure. But if I was driving at relativistic speeds, would more light hit my windshield than if I was just standing still? If yes, then the same logic does apply as for rain. – Alex Broadhead Aug 07 '15 at 00:34
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    Your question did not specify you were driving at relativistic speeds. It specified a practical question about you driving on the freeway versus being parked which both occur at much lower than relativistic speeds. If you were able to travel at such speeds, you'd have more to worry about than sunburn. – nluigi Aug 07 '15 at 07:34
  • Why does the speed I'm driving affect the logic of the interaction? – Alex Broadhead Aug 08 '15 at 18:44