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The most popular blog posts about science & space on Hacker News. 2,038 posts.

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1806

The Geometry of Color Perception

The previous pages have explained three very different methods for defining a color: (1) the measurement of the color stimulus as a spectral emittance or reflectance curve in colorimetry ; (2) the proportional responses to the stimulus by the L , M and S cones, represented as a chromaticity diagram ; and (3) the…

1808

$5 whale listening hydrophone making workshop

Whale songs were first noticed by accident, when analysts tracking Russian submarines at the height of the cold war heard cetacean interference instead. An engineer sent some recordings to Roger Payne, a biologist friend of his, who did something that proved pivotal: he played the hours-long recordings on his hi-fi at…

1810

The Gravo-Thermal Catastrophe

In 1962, V. A. Antonov did some remarkable simulations showing that in Newtonian mechanics, gravitating systems can violate the usual rules of thermodynamics. Instead of reaching equilibrium they c…

1811

Apollo 11 and Other Screw-Ups

(A paper presented to the 27th annual Guidance and Control Conference of the American Astronautical Society (AAS), in Breckenridge, Colorado on February 6, 2004, and designated AAS 04-064. This version includes additional illustrations and comments, and several minor corrections.)

1813

How we gave colors names

“Who in the rainbow can draw the line where the violet tint ends and the orange tint begins? Distinctly we see the difference of the colors, but where exactly does the one first blendingly enter in…

1814

Closed access means people die

Jenny Molloy and I have been representing the Open Knowledge Foundation at the Open Science Summit and we presented the Open Research Reports (ORR) project. The slides we used are at http://dl.dropbox.com/u/6280676/orr.pptx . I expect that at some stage we’ll be on the video record (last year’s was very useful and…

1819

Lunar Terminator Paradox

There's an optical illusion known by names like the "lunar terminator paradox". This has much discussion and descriptions online, but none made sense in my head, so I wrote this program to figure out what was going on. The paradox:

1825

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.