Tractor beams make intuitive sense. Matter and energy interact with each other in countless ways throughout the Universe. Magnetism and gravity are both natural forces that can draw objects together, so there’s sort of a precedent.
But engineering an actual tractor beam is something different.
A tractor beam is a device that can move an object from a distance. The idea comes from a 1931 sci-fi story called Spacehounds of IPC:
“There is such a thing as a ray screen, you kill-joy, and there are also lifting or tractor rays —two things I’ve been trying to dope out and that you’ve been giving me the Bronx cheer on. The Titanians have had a tractor ray for ages — he sent me complete dope on it — and the Jovians ’ve got ’em both. We’ll have ’em in three days, and it ought to be fairly simple to dope out the opposite of a tractor, too — a pusher or pressor beam.” — from Spacehounds of IPC by Edward Elmer “Doc” Smith
If science fiction had anything to say about it, tractor beams would already be commonplace, and we could thank Star Trek and Star Wars for their proliferation.
But tractor beams do already exist, though their reach is only microscopic.
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