You know like the kind that go on a window or bathroom mirror or on the wall or in the shower. They need the atmosphere pushing down on them to work, right?

  • Shurimal
    31•1 month ago

    Velcro, or maybe Van Der Waals force, or maybe whatever the hell makes gauge blocks stick to each other.

    • @ricecake
      18•1 month ago

      I like the gauge block notion. A (quick) search says that it’s a combination of surface tension from the oils they’re coated in, suction (gone for us), and the super flat surfaces slightly exchanging electrons and bonding in close proximity.

      I’m a fan of the surface tension angle as the “rocket of suction cups”, since it’s got that “non-binding force” element, where welding or glue feels different, and Velcro feels like a tangle.
      It’s “pull-y” where suction is “push-y”.

      Now the question is would surface tension grab something in a vacuum the way it does outside of one. I know you’d have water sublimate off, so it’s questionable to me.

    • @[email protected]
      2•1 month ago

      If it’s metal, just rub a bit of it against another piece of metal and it will cold weld/fuse to it.

      • @[email protected]
        1•1 month ago

        This only works on “virgin” metal iirc - if it’s been exposed to Earth’s atmosphere, it won’t work. If you shave off some from the surface I believe it works again.

        • @[email protected]
          1•1 month ago

          Like I said- “rub it”. The oxidized layer on metal is very, very, thin. It doesn’t take much at all to get rid of it.

          • @[email protected]
            1•1 month ago

            I didn’t realize that the layer was thin enough to rub away with minimal friction. I’d learned about this years ago so I could be misremembering things, but the source I read made it out as if it wasn’t a major concern with space exploration because it took substantial effort to cold weld things that had been exposed to air.