Why are there no animals with three legs?

If "Why?" is the first question in science, "Why not?" must be a close second. Sometimes it's worth thinking about why something does not exist.

Physicists read Maxwell's Demon's mind

Pioneering research offers a fascinating view into the inner workings of the mind of 'Maxwell's Demon', a famous thought experiment in physics.

Can light orbit a black hole?

Since black holes are the most powerful gravitational spots in the entire Universe, can they distort light so much that it actually goes into orbit? And what would it look like if you could survive and follow light in this ...

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