Rosetta finds molecular oxygen on comet 67P (Update)

Stunned scientists announced Wednesday the unexpected discovery of large quantities of oxygen on a comet which streaked past the Sun in August with a European spacecraft in tow.

Dual internal clocks keep plant defenses on schedule

Time management isn't just important for busy people—it's critical for plants, too. A Duke University study shows how two biological clocks work together to help plants deal with intermittent demands such as fungal infections, ...

Water could have been abundant in the first billion years

How soon after the Big Bang could water have existed? Not right away, because water molecules contain oxygen and oxygen had to be formed in the first stars. Then that oxygen had to disperse and unite with hydrogen in significant ...

Photosynthesis has unique isotopic signature

Photosynthesis leaves behind a unique calling card, a chemical signature that is spelled out with stable oxygen isotopes, according to a new study in Science. The findings suggest that similar isotopic signatures could exist ...

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