Can you pee on the moon?

Question

If, in some miraculous way, one were able to pee standing on the surface of the Moon, what kind of arc would it create?

Answer

Dr Chris Messenger from the University of Glasgow was on hand to help me with Michael’s question…

  • The moon’s gravity is 16% of that on Earth, which means the pee will travel in a straighter arc and about 2.5 times further
  • In a uniform gravitational field objects travel in a parabolic arc – sort of a ‘u-shape’
  • On the moon, the atmosphere is so thin that the pee would follow a very accurate parabola, as can be seen with the dust thrown up by the lunar rover
  • The low atmospheric pressure on the moon would immediately boil the pee which would then fall to the surface as steam
  • Despite the low temperature of the moon (as low as -170 degrees Celsius), the pressure reduces the boiling point of water so dramatically that your pee would boil way below body temperature of 37 degrees Celsius, which is why it immediately turns to steam
  • The freezing temperature of water on the moon also occurs in the same range as the boiling point, which means that the steam molecules will then freeze into yellow ice crystals

You can listen to the full version of Question of the Week with the Naked Scientists here.

Can ants feel pain?

Question

Carol asks: Can ants feel pain?

Answer

I went crawling around for the answer with York University’s Eleanor Drinkwater…

  • Ants can sense that they’ve been harmed and react but this is different to actually feeling pain
  • Nociception is the sensory nervous system informing the brain that you’ve been hurt, whereas pain is an unpleasant sensation with a negative emotional response
  • One can occur without the other eg. when playing sports you often don’t realise that you are injured until afterwards, or people who have lost limbs experience phantom limb pain
  • Robots can also be programmed to experience nociception without experiencing pain, for example in the video game The Sims characters will jump around if they’re burnt by fire
  • We currently know very little about insect expressions of pain, but we do know that the pain expression systems are different to those in mammals, meaning that insects are likely to experience pain in a different way to humans
  • In short, the jury is still out, so best to be nice to any ants that you may come across!

Part of the Naked Scientists Question of the Week series – you can listen to the full version here.

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