Earth’s heat

How does earth generate 30-44 terawatts (1 terawatt = 1,000,000,000,000 watts) of heat to churn liquid iron in the outer core inside our planet' To find out the answer, an international team of scientists has measured the planet’s underground radioactivity. After studying a few meteorites, geologists have found that the radioactivity contributes a chunk of the heat ' 19 terawatts.

Hybrid species

New animal species arise by splitting off from an evolutionary lineage. But Penn State University researchers have found that honeysuckle maggots are the result of hybridisation between two fruit maggots, and they have spent hundred generations interbreeding, reports Nature. Hybridisation, used to produce new plant species, may be widespread in animals too, say the researchers.

Longevity gene

For little round worms Caenorhabditis elegans, how well they respond to stress predicts how long they will live, reports Nature Genetics. Those having more active stress proteins, produced by a gene, coped well with stress and lived much longer than others with less active proteins, writes a researcher.