Slashdot Mirror

← Back to Stories (view on slashdot.org)

There's No Wind Chill On Mars

Posted by Soulskill on from the it's-not-the-cold,-it's-the-aridity dept.

sciencehabit writes: Even though daytime temperatures in the tropics of Mars can be about –20C, a summer afternoon there might feel about the same as an average winter day in southern England or Minneapolis. That's because there's virtually no wind chill on the Red Planet, according to a new study — the first to give an accurate sense of what it might feel like to spend a day walking about on our celestial neighbor. "I hadn't really thought about this before, but I'm not surprised," says Maurice Bluestein, a biomedical engineer and wind chill expert recently retired from Indiana University–Purdue University Indianapolis. The new findings, he says, "will be useful, as people planning to colonize Mars need to know what they're getting themselves into."

6 of 110 comments (clear)

  1. Wind chill on a space suit? by michelcolman · · Score: 5, Insightful

    Wind chill works because of evaporation on the skin, right? I don't think anyone is going to be walking around on Mars outside a biosphere, in a T-shirt. If you're wearing a space suit, wind chill is totally irrelevant or am I missing something?

    1. Re:Wind chill on a space suit? by Chrisq · · Score: 5, Informative

      Wind chill works because of evaporation on the skin, right? I don't think anyone is going to be walking around on Mars outside a biosphere, in a T-shirt. If you're wearing a space suit, wind chill is totally irrelevant or am I missing something?

      Only partially - its also the continual replenishment of cold air against the skin. You don't sweat when you'r really cold.

    2. Re:Wind chill on a space suit? by mysidia · · Score: 5, Informative

      Wind chill works because of evaporation on the skin, right?

      Aside from the affects of evaporative cooling: wind chill also works due to air movement.

      Moving air dissipates heat more quickly than stagnant air.

      By the way.... since there is essentially little or no air on mars... there is essentially no wind, so it follows and is quite expected that there would be no wind chill; however, this is not very interesting, because: humans cannot survive in this environment.

      It is necessary to have an artificial environment that includes air.

      The environment that includes air.... if it is large enough: will be subject to wind chill, whenever a sufficient difference in pressure or temperature from one area another is large enough to cause quick air movement.

    3. Re:Wind chill on a space suit? by xororand · · Score: 5, Informative

      Unfortunately the atmospheric pressure on Mars (0.6 kPa) is far below the Armstrong Limit (6.3 kPa) at which your blood boils at body temperature.
      https://en.wikipedia.org/wiki/...

    4. Re:Wind chill on a space suit? by Anonymous Coward · · Score: 5, Funny

      Unfortunately the atmospheric pressure on Mars (0.6 kPa) is far below the Armstrong Limit (6.3 kPa) at which your blood boils at body temperature.
      https://en.wikipedia.org/wiki/...

      I thought the Armstrong limit had to do with how many times you can win a Tour de France without getting busted for doping?

  2. Wind chill on a solar collector by Anonymous Coward · · Score: 5, Interesting

    Not too relevant for people, but if you're designing a solar collector to warm an underground settlement this is pretty important. You would still need some large mirrors to get enough energy to be useful. But the low atmospheric pressure would dramatically reduce the insulation requirements. Maybe just a couple of layers of reflective foil around the pipework and behind the collector to reduce radiation losses.

    Similarly, if you're planning a high pressure (from a mars perspective) greenhouse this has a real bearing on heat losses.