Solar Wind Samples Add Mystery to Earth's Genesis

摘要

Earth and other rocky planets are not made out of the solar system's original starting material, two new studies suggest. Scientists examined solar particles snagged in space by NASA's Genesis probe, whose return capsule crash-landed on Earth in 2004. These salvaged samples show the sun's basic building blocks differ significantly from those of Earth, the Moon and other denizens of the inner solar system, researchers said. Nearly 4.6 billion years ago, the results suggest, some process altered many of the tiny pieces that eventually coalesced into the rocky planets, after the sun had already formed.