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Science & Space

The most popular blog posts about science & space on Hacker News. 409 posts.

2021
363

The Great Filter – Are We Almost Past It? (1998)

Combining standard stories of biologists, astronomers, physicists, and social scientists would lead us to expect a much smaller filter than we observe. Thus one of these stories must be wrong. To find out who is wrong, and to inform our choices, we should study and reconsider all these areas. For example, we should…

367

The Breeder's Equation

R is the response to selection, S is the selection differential, and h 2 is the narrow-sense heritability. This is the workhorse equation for quantitative genetics. The selective differential S, is the difference between the population average and the average of the parental population (some subset of the total…

369

Synthetic Cartilage (2020)

The thin, slippery layer of cartilage between the bones in the knee is magical stuff: strong enough to withstand a person’s weight, but soft and supple enough to cushion the joint against impact, over decades of repeat use. That combination of soft-yet-strong has been hard to reproduce in the lab. But now, Duke…

370

Maps Of Matter

Status: Rough working notes – me thinking aloud. Speculative, and likely contains errors, misconceptions, and omissions; thoughtful, informed comments are welcome. Intended for a general scientifically curious audience, not requiring much detailed specialist background.

372

The Joy of Condensed Matter

I published a slightly different version of this article in Nautilus on February 24, 2021. Everyone seems to be talking about the problems with physics: Woit’s book Not Even Wrong, Smolin&#82…

373

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…

386

How the brain navigates cities

An MIT study suggests our brains are not optimized to calculate the shortest possible route when navigating on foot. Instead, pedestrians use vector-based navigation, choosing “pointiest” paths that point most directly toward their destination, even if the routes are longer.