back to article Mercury, the closest planet to the Sun, surely has no frozen water, right? Guess again: Solar winds form ice

Mercury, the innermost planet in the Solar System, reaches searing temperatures. Yet ice still manages to exist on its rocky surface. How? The heat from our star actually contributes to the formation of ice, according to a paper published in The Astrophysical Journal Letters on Monday. Mercury’s surface can get up to 400 …

  1. Pascal Monett Silver badge

    Interesting process

    One major point that makes this whole thing possible is the lack of atmosphere. If Mercury was massive enough to hold an atmosphere, no ice would be possible because the atmosphere itself would be hundreds of degrees.

    But I guess it's only Jupiter-sized planets that can hold an atmosphere when the orbit is that close to a star. Any rocky planet that close will have the solar wind strip it bare in a few million years (a galactic blink of an eye).

    1. Def Silver badge

      Re: Interesting process

      Given that the length of a day on Mercury is 176 Earth days, I'm not sure that the atmosphere would be that hot. At least not uniformly, and almost definitely not at night.

      1. SkippyBing Silver badge

        Re: Interesting process

        I think the convection currents would ensure the atmosphere was continuously mixing with cold air from the night side dragged into the light by the rapidly rising hot air.

        1. Brewster's Angle Grinder Silver badge

          A loud place

          "...convection currents..."

          SORRY, WHAT DID YOU SAY? YOU'LL HAVE TO SPEAK UP. I COULDN'T HEAR YOU OVER THE SOUND OF THE HURRICANE-FORCE WINDS.

      2. Muscleguy Silver badge

        Re: Interesting process

        Except such tidal slowing will not have been in operation at the start of Mercury's formation. It is still too close to Sol to have retained an atmosphere.

        And as we see with Mars and its atmosphere, gravity alone is not enough. You also need a decent enough magnetic field to stop the solar wind stripping your atmosphere over time. Which is what happened to Mars which is far enough from Sol that it retains a very thin atmosphere.

        The idea that we can terraform the Martian atmosphere by bringing in material from the asteroid belt falls on this rock. Anything we add will just get eroded away so we will have to keep adding stuff to Mars' atmosphere until Sol goes red giant.

        1. This post has been deleted by its author

        2. SkippyBing Silver badge

          Re: Interesting process

          Honestly if we get to the stage we can terraform Mars I'd expect rigging up a magnetic field wouldn't be a problem.

          1. Brewster's Angle Grinder Silver badge

            Re: Interesting process

            I reckon we put in a new moon. We could "borrow" one of the dwarf planets. If we got it in close enough it would stir up Mars' interior and, given a few millions years, get the magnetic field humming again.

            And, much like the Earth/Moon system, our new Mars/moon system would orbit its barycentre. So, if we plum for the obvious choice, we'd have Ceres in parallel with Mars.

            Sorry. That was a helluva lot of set up for a really lame joke.

    2. Palpy Silver badge

      Re: Interesting process... with iron...

      One of the hot Jupiter exoplanets (WASP-76b) has been shown to have iron vapor in the atmosphere. Like Mercury, it's tidally locked to its star, so on the dayside the temp runs around 2400 deg C. Strong winds appear to carry the vapor from the dayside into the night, where the temperature drops to around 1400 deg C, cool enough for the iron vapor to condense into droplets and rain out.

      Science daily link: https://www.sciencedaily.com/releases/2020/03/200311121832.htm

      1. jake Silver badge

        Re: Interesting process... with iron...

        Wot, no ElReg link? Heathen!

        https://www.theregister.co.uk/2020/03/11/wasp76b_molten_iron_rain/

  2. Blackjack

    So there is ice and fog in Mercury?

    Sailor Mercury (From Sailor Moon) ended being scientifically correct?

    1. Anonymous Coward
      Anonymous Coward

      Re: So there is ice and fog in Mercury?

      Just have to sort out Pluto now...

      1. HildyJ Silver badge
        Holmes

        Re: So there is ice and fog in Mercury?

        Already sorted. Pluto definitely has ice (a lot of it). However, there is no water in the atmosphere so no fog.

    2. bombastic bob Silver badge
      Devil

      Re: So there is ice and fog in Mercury?

      I would expect there to be a lot of heavier elements on Mercury, too - rare earths and gold and platinum and uranium and other such things, in higher concentrations than Earth. Proximity to the sun - outer planets are less rocky, inner planets more rocky. I expect the "rockiest" one to be Mercury.

      The nights are long - you could land on the dark side and conduct mining operations during the night, when it's cold instead of roasting [easier to heat people and things than to cool them]. And apparently there'd be water there as well [like on the moon I guess].

      I think the planet mercury in Japanese is 'Suisei' - 'liquid star', best understanding. So the Sailor Mercury reference to water, etc..

  3. TheProf Silver badge
    Devil

    What I took from the video

    If you want to keep ice on Mercury you have to stick it where the Sun don't shine.

    1. David 132 Silver badge
      Happy

      Re: What I took from the video

      All the way to the 7th planet? Seems a long way to go for some ice.

      1. The Oncoming Scorn Silver badge
        Pint

        Re: What I took from the video

        https://www.youtube.com/watch?v=0XIncbNbIP0

  4. Woza
    Joke

    When hell

    Freezes over?

    1. roytrubshaw
      Headmaster

      Re: When hell

      <Pedant>According to Dante, hell *is* frozen; at the centre anyway.</Pedant>

      1. jake Silver badge

        Re: When hell

        Fortunately, today's boffins don't have to take instruction from early 14th century allegory, despite the best efforts of many pig-ignorant Western politicians.

        (Apologies to any pigs who may be reading this. It's just an expression, no offense intended.)

        1. Anonymous Coward
          Anonymous Coward

          Re: When hell

          OINK!!

    2. bombastic bob Silver badge
      Trollface

      Re: When hell

      "You've frozen EVERYTHING! Do you have any idea how long it takes to get the pilot lit?"

      (from an Animaniacs cartoon - they went to hell, yeah - and froze it over)

  5. JulieM Silver badge

    Temperatures can soar over 400C

    Temperatures can soar over 400C, and yet somebody will inevitably moan that they are too cold.

    (Coat? I don't need no stinkin' coat! It's double figures out!)

    1. phuzz Silver badge
      Thumb Up

      Re: Temperatures can soar over 400C

      It's always in double-figures outside if you measure in Kelvin.

      1. The Nazz Silver badge

        Re: Temperatures can soar over 400C

        "always double figures in Kelvin?"

        Except when it's triple figures? Which is quite often.

        Also, -10deg C is double figures. No coat yet here in tough West Yorkshire.

    2. Muscleguy Silver badge

      Re: Temperatures can soar over 400C

      When going for a run in the great outdoors anything over 5C and I'm in shorts. I will wear a jacket (breathable) for rain up to 10C but the chances of getting exposure above 10C (while generating lots of personal heat) are very much less.

      I also grew up running in Auckland, NZ and therefore learned both a tolerance of being VERY wet while running and enjoying running in the rain (it temporarily helped with the humidity and was cooling).

      So no coat above 10C, fine. If I'm running.

    3. HildyJ Silver badge
      Devil

      Re: Temperatures can soar over 400C

      We Muricans don't use Frenchie's numbers.

      1. jake Silver badge

        Re: Temperatures can soar over 400C

        Celsius was Swedish, not French.

        1. W.S.Gosset Silver badge

          Re: Temperatures can soar over 400C

          Sorry jake, HildyJ's correct. The scale we use was created by a Frenchman. Jean-Pierre Christin.

          The scale Celsius created was identically centigrade but inverted: water boiled at 0° and froze at 100°.

          1. jake Silver badge

            Re: Temperatures can soar over 400C

            By that logic, the first person to turn over an hourglass invented a new thing.

            1. W.S.Gosset Silver badge

              Re: Temperatures can soar over 400C

              Well-lllll.... the chap who picked up the hourglass and observed that it made more sense for time to run forwards than backwards, so maybe the numbers being jotted down should go up over time rather than down, certainly has developed something markedly more sane and useful and contributory than the first.

              1. jake Silver badge

                Re: Temperatures can soar over 400C

                I guess it's a good thing that scientists world-wide have decided to call the scale "Christin", then, as they should know.

                1. W.S.Gosset Silver badge

                  Re: Temperatures can soar over 400C

                  M. Christin would be far from the first and far from the last person to have his/her contribution written out of the science paradigm by Tha Boyz. :) E.g., the chap who discovered that arteries work precisely the opposite way round from "medical science"'s understanding, not only did not get the Nobel Prize for it, but the 2 chaps who excitedly asked to help him out on some subsequent work DID. I was there at the Royal Institution when its head did the scientific community version of tearing the Nobel Committee a new arsehole for this. Very publicly with the lights on him, cameras rolling, going internationally. Didn't work -- the committee is as answerable as ICANN. There is more arbitrariness and bitchiness in "science" than you can poke a pointed stick at.

                  Having said that, "Celsius" works better as a scale-name than Christin. I reckon. ;)

      2. aks Bronze badge

        Re: Temperatures can soar over 400C

        Remind me again where Farenheit was from. Germany, wasn't it?

        1. Michael Wojcik Silver badge

          Re: Temperatures can soar over 400C

          He was from Not-France. Freedom temperature scale!

          (Actually, the Farenheit scale makes some sense; its standard points, 32 and 96, are separated by a power of two so thermometers could be graduated by successive subdivision. Centigrade's usefulness is primarily in its connection to the rest of SI, and that came along much later.)

  6. Annihilator Silver badge

    Closest

    "Mercury, the closest planet to the Sun"

    Mercury is also, currently, the closest planet to Earth. Strangely, on average it's the closest planet to Earth (about 45% of the time) with the rest of the time split between Mars and Venus.

    It's also (on average again), the closest planet to all other planets in the solar system, which still blows my mind.

  7. Michael Wojcik Silver badge

    Disappointed

    No comments about making water, or about the solar winds of Uranus? What are we, a bunch of adults?

    1. Lotaresco

      Re: Disappointed

      OK, if you insist. I found out when camping that making water on a hot rock isn't a good idea. It's the smell it causes that is the problem.

  8. bombastic bob Silver badge
    Coat

    "Making Water"

    couldn't help myself...

    /me gives thumbs-up for interesting article on the way out - coat, please

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