On the Radar

The pick of the science news

How Saturn got its rings

Could Saturn’s rings and inner moons have arisen from a large moon that crashed into the planet? A simulation described online in the journal Nature this week suggests so.

The icy composition of Saturn’s rings pointed Southwest Research Institute researcher Robin Canup in Colorado to a scenario where a large moon spiralled into the planet – as the satellite migrated towards Saturn, planetary tidal forces stripped the moon’s icy outer layers until its rocky core eventually collided with the planet.

“The result is a pure ice ring much more massive than Saturn’s current rings,” she writes. “As the ring evolves, its mass decreases and icy moons are spawned from its outer edge.”

Monitoring the X Factor

Millions of people tuned into the X Factor finals last weekend – but how did we feel as the contestants sang and got eliminated and then Matt Cardle eventually won?

Researchers in Dublin noted comments on Twitter using analysis developed at Clarity, a Science Foundation Ireland- funded partnership between UCD, DCU and Tyndall National Institute.

“Our systems analysed a sample of almost 70,000 tweets in real time from the stream of probably over half a million tweets,” said Prof Alan Smeaton. “One Direction were neck-and- neck with Matt until they were evicted, and then after that there was only ever going to be one winner.”

Whistling caterpillars

Next time you are passing a leaf listen carefully – can you hear anything? It turns out at least one type of caterpillar larva can whistle in response to a threat.

Canadian researchers discovered that walnut sphinx caterpillars emit a squeak by pulling their heads back, compressing their bodies and forcing air out of structures called spiracles, which results in whistles.

“Birds responded to whistling by hesitating, jumping back or diving away from the sound source,” researchers say.