Can two things be apart but touch ?

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Offline neilep

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Can two things be apart but touch ?
« on: 04/04/2011 19:41:59 »
Dearest Apartologists,

Can two things be apart but touch ?

Effectively could  2 surfaces be an atom apart and not touch ?...could they then slide beside each other with ease ?..and could light be detected shining through the gap ?...If not...what would be the minimum distance apart for two objects to allow light to travel through the gap ?

whajafink ?

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Offline lab monkey

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Can two things be apart but touch ?
« Reply #1 on: 14/04/2011 17:52:04 »
It depends on how ewe define apart, which atom you're talking about and where the "edge" of the atom is.

2 items, an "atom" apart couldn't slide past eachother with ease.  At that sort of distance there would be massive electrical and atomic forces in play.  You'd probably find they repel or they form bonds - depends on the actual atoms.

I don't know if light would be able to "pass through" a gap of that size.  The shortest wavelength of visible light is much larger than the average diameter of a hydrogen atom (380nm compared to 0.1nm or so) so, even if it could, you wouldn't be able to see the atom...


Offline wolfekeeper

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Can two things be apart but touch ?
« Reply #2 on: 15/04/2011 16:30:35 »
He seems to be asking whether it's possible to build a non contact bearing.

And the answer is yes, magnetic bearings can keep objects apart, with a significant gap; and there's no minimum distance. The minimum distance for light to travel through it would be its wavelength, a few hundred nanometres (about a millionth of a metre, a thousandth of a millimetre).

Whether that still counts as 'touching' is largely semantic; touching is due to electromagnetic forces between atoms anyway, so a magnetic bearing can fairly reasonably be considered to be touching.
« Last Edit: 15/04/2011 16:32:41 by wolfekeeper »