Giant planets ran amok soon after Solar System ’s birth

In its youth, the Solar System underwent a momentous upheaval: Gravitational tugs between the giant planets threw them off-track, causing Jupiter’s orbit to jump closer to the Sun, while Saturn, Uranus, and Neptune were flung outward. The gravity of the rampaging giants scattered Pluto and other icy bodies to the Kuiper belt, shepherded the asteroid belt into its current location, and sent countless bodies crashing into the inner Solar System. For many years, researchers believed this “giant planet instability” occurred 600 million years after the Solar System’s birth 4.57 billion years ago, based on the ages of impact craters mapped on the Moon. Recently, evidence has mounted that it occurred much earlier . And now, some researchers are homing in on a more precise date, just 60 million years after the Solar System’s formation, based on an analysis of rare meteorites derived from an ancient asteroid family, published today in Science . Other recent work seems to corroborate the date: the impact history captured in common meteorites, the formation history of the icy dwarf planet Haumea, and the earliest known mineral crystals found in Moon rocks retrieved by Apollo astronauts. “When you put it all together, that’s a lot of evidence for impacts all right around 60 million years,” says Steven Desch, an astrophysicist at Arizona State University. Dating the event is not simply a bookkeeping exercise. The chaos would have influenced ...
Source: Science of Aging Knowledge Environment - Category: Geriatrics Source Type: research