Federal regulators have endorsed General Motors’ proposal to revise the structure surrounding the Chevrolet Volt’s battery pack and modify its coolant system, a move GM says will better protect the pack and reduce the risk of an electrical fire in the days and weeks after a crash.

The redesign follows “a formal safety defect investigation” by the National Highway Traffic Safety Administration into the Chevrolet Volt’s lithium-ion battery. The probe, announced Nov. 25, was prompted by two fires that followed crash tests. Although the agency was unaware of real-world crashes causing fires, it...

By Mark Brown, Wired UK

The International Earth Rotation and Reference Systems Service (IERS) in Paris — the grand arbiters of time on our big blue marble — has declared that a leap second will be introduced on 30 June, 2012.

We used to use the Earth’s dutiful rotation as a way of measuring time. It pirouettes on its axis once every 24 hours, which can then be divided into minutes and seconds. But the Earth’s rotation is annoyingly irregular, with some days ending up being a tiny bit longer or shorter than others.

There’s nothing science hates m...