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摘要

The oldest known relative of starfish looked like a light bulb. Fossils of a bulbous animal called Helicocystis moroccoensishave been discovered in rocks 510 million years old. Five grooves spiralled around the bulb to the mouth at the top. You might think the best place for solar panels in the US would be in sunny California, but that's not the case. Solar panels would cut more greenhouse gas emissions in cloudier states like Nebraska, provided they are close to coal-fired power plants and can compete with them for business (PNAS. doi.org/m29).