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Bitcoin’s bull market

The digital currency bitcoin is nearing the $10,000 mark for a single bitcoin — a 1240 per cent increase from its price of $730 last year. In early October, a bitcoin cost around $5000. The jump in price may be spurred by a glut of new buyers. Coinbase, the largest bitcoin exchange in the US,added nearly 100,000 accounts last week.

No asteroids needed

Asteroids have been seen as the best candidates for how life could spread between planets. But it may also be possible for space dust to collide with biological particles in a world’s upper atmospheres at high enough speeds to send them into space ().

Big-beaked birds

Species usually change at a snail’s pace, but not always. North American birds called snail kites have developed larger beaks in less than a decade, in order to eat invasive island apple snails that are much larger than the snails they used to eat – though contrary to many reports they have done so using their existing genes, not as a result of evolution changing these (Nature Ecology & Evolution, ).

Teen brains

Adolescents’ brains aren’t developed enough to adapt to high-stakes situations, which may explain why some engage in risky activities. Brain scans of teens playing a game found that the older they are, the better they adapt their behaviour to high-risk or low-risk situations (Nature Communications, ).

Rocks on the move

Huge, mysterious rocks high on sea cliffs were dumped there by storms and tsunamis. Boulders weighing 30 tonnes each on Annagh Head, Ireland, were carried there by centuries of storms, while similar boulders on the Matheson Formation in New Zealand were probably deposited by a single, massive tsunami (PNAS, ).