Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: LateJunction on 29/06/2020 10:51:04
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This is my first post to this forum; I hope it doesn't immediately characterise me as a fool...
I am interested to know if there is a limit to how small things can be.
In the last 100,000 years of humanoid history our understanding of things has seen their size shrink by - a rough guess - between 5 and 10 orders of magnitude; from a large pebble in a river to the atomic nucleus. But the rate of shrinkage in the last 100 or so years has been greater than that of the previous 100,000 years. How far will it shrink in the next 100 years? Which is another way of asking how many orders of magnitude are we away from the infinitely small? Is there such a state ?
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"Things" haven't changed, but our ability to see the very large (galaxies 30,000,000,000 light years away) and the very small (atoms) and to perceive and detect even subatomic particles, has developed very rapidly in the last few hundred years.
That said, Democritus postulated atoms around 400 BC and even the idiots enforcing Christianity insisted that the universe was a bit bigger than the Earth, even if it all revolved around the Pope. What's missing right now is any plausible hypothesis that there might be something significantly smaller than an electron, or bigger than the observable universe. It's tempting to think that a quark or neutrino might be in some way smaller than an electron, but Heisenberg intervenes and suggests that size is a bit meaningless on that scale. Likewise I'm pretty sure that there's a lot more, and a lot more interesting, outside the observable universe, but as we can't observe it (by definition) it has to remain hypothetical.
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It breaks down as you zoom in. and some of the particles we define are 'point particles' as a photon, you can't scale it up because it hasn't a size. That's one reason for thinking of everything as existing of a 'field', nothing material at all. The matter becoming a question of what scale you use.
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added some stuff.
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This is my first post to this forum; I hope it doesn't immediately characterise me as a fool...
No it doesn’t do that, it is a reasonable question and the answers are not obvious.
To add to what Alan says, many physicists believe that there is no limit to how small something could be, but there appears to be a theoretical limit to what size we might be able detect. If 2 particles are closer than what is called the Planck length (about 1.6×10−35m) then we would be unable to know they were separate items.
That said, Democritus postulated atoms around 400 BC
Aristarchus postulated a heliocentric system in 3BC and even suggested that stars were distant suns. He also wrote a treatise on the size and distance of the sun and moon. His ideas were largely ignored because they clashed with those of Aristotle and Plato.
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That's one reason for thinking of everything as existing of a 'field', nothing material at all.
And it is at this point that my ability to understand seems to fail me: this word 'field'. The more I think about it the more the words like 'ether' or 'phlogiston' come to mind. Do we not have words, or non mathematical concepts, which can help us lesser minds understand what a field is and how it can exist? I remember thinking in my physics lectures in the 1960s that electro-magnetic radiation was nothing more than a set of equations. 'Field' sounds awfully similar.