Most people know their blood type, treat it as a fixed personal fact like eye colour, and have never wondered what it is.
It is a molecule. Specifically, blood type…
The useful way to read these is as solutions rather than as homes. Each one is addressing a specific physical problem, and the structure follows from the problem rather than…
The recurring problem is the same everywhere: sleep appears to be necessary, and being asleep is dangerous. Almost every solution below is a compromise between those two facts. Here are…
Animal navigation combines several systems at once, which is why removing one rarely stops an animal entirely. Here are seventeen of the tools involved.
1. Reading the Earth's Magnetic Field…
Source: Wikipedia
There is an object in a museum case in London that does something a piece of fourth-century glass has no business doing.
Look at it with the light coming…
Almost nobody looks at a dark night sky and thinks it requires explanation. It is dark because the sun has set, which seems sufficient.
It is not sufficient, and noticing…