5 Most Incredible Discoveries of the Week

Confirmation of a moon-creating blast and an insight into why koalas do what they do make the list:

• Finally, Evidence of Other World That Helped Form Moon: A new analysis of three lunar rocks bolsters an old theory some thought too simple: that the moon was created when another planet, Theia, crashed into Earth billions of years ago. For the first time, scientists see evidence of long-lost Theia in those rocks.
• Scientists Discover Why Koalas Hug Trees: Researchers have uncovered the science behind a habit that seems, well, cute: Koala bears hug trees to cool themselves. It turns out that tree trunks can be up to 12 degrees cooler than the air, and with Australia's recent hot spells rising well above 100 degrees, koalas get extra huggy.

• World's Oldest Pair of Pants Found: Archaeologists working at an ancient graveyard in western China have unearthed what they say is the oldest pair of pants ever found. They seemed to have belonged to horse riders who lived about 3,000 years ago, and they were pretty stylish to boot.
• Scientists Find Bat Feared Extinct: Researchers studying bats in Papua New Guinea came across a long-lost friend in their nets: a female identified as a New Guinea big-eared bat. It's noteworthy because no specimen has been seen in 124 years, although this particular specimen is no longer among us, either.
• How Hungry Maggots Spurred Rapid Evolution: Two kinds of crickets on separate Hawaiian islands seem to have figured out relatively quickly that making noise to attract mates also attracts predator flies (which then, grossly, leave maggots on the crickets that eventually kill them). The evolutionary solution? The crickets learned to shut up.

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