Top posts

Every blog post that took off on Hacker News, ranked by the votes of its best submission. 399 posts.

Science & Space
2022
362

How far behind a plane is its noise?

If you’re ever near a relatively low flying airplane, you may have noticed that it sounds like it’s in a different spot in the sky than where it actually is. You can hear the loud engines, and your ears tell you it should be in one place, but your eyes tell you it’s clearly well ahead of its noise. It’s a funny visual…

377

Noether's Theorem in a Nutshell (2020)

Noether's theorem is an amazing result which lets physicists get conserved quantities from symmetries of the laws of nature. Time translation symmetry gives conservation of energy; space translation symmetry gives conservation of momentum; rotation symmetry gives conservation of angular momentum, and so on.