Blogs lezen is verslavend. Links du jour, van bij David Harris’ Science News:
- 25 friends + boredom = Mexican wave
It takes about 25 bored fans in a stadium to start a Mexican wave, reports a study in Nature. The title of the paper “Mexican waves in an excitable medium” brings a new meaning to the usually dry scientific definition of “excitable medium”. More at Science Nature Update
- How to balance a stick on your finger
With practice, most people have no trouble balancing a long stick on the end of their finger. But as the stick gets shorter, the challenge is greater. The biggest problem in balancing the stick is that human reaction times can be slower than the time it takes for the stick to fall. An analysis of stick balancing shows how the human nervous system copes with balancing problems even for 98% of the time when reaction time isn’t fast enough. A new model suggests that the nervous system introduces random motions to a person’s finger. Surprisingly, these random motions can help stabilize the stick. This idea of introducing randomness to an unstable situation and thereby creating something more stable has been previously recognized and used in human-made technologies such as the design of high performance aircraft but this study shows it naturally at work in the human nervous system. The authors suggest that these techniques may also be applicable to making buildings more earthquake-proof and to making two-legged walking robots.
- Explaining the canals on Mars
When Percival Lowell first observed Mars through his telescope in 1894, he thought he saw evidence for past life on the red planet. What appeared to be a network of canals radiated outward from a point and they always seemed to be facing the Earth. However, a new understanding of the problem prompted by a July Sky & Telescope article is discussed in today’s New York Times.
Fascinerend. Ik voeg hem meteen aan m’n blogroll toe.