Dating earth meteorites
It came from a different asteroid than the Chelyabinsk bolide, but both experienced major impacts at roughly the same time as the Moon-forming giant impact.
We argue these impact melts were created when high velocity debris from the Moon-forming impact event hit the parent asteroids of the Chelyabinsk and Novato bolides and heated near-surface material.
(2004, Simulations of a late lunar-forming impact, Icarus 168, 433-456).
Credit: Robin Canup, Southwest Research Institute Intriguingly, some debris may have also returned to hit the Earth and Moon after remaining in solar orbit over timescales ranging from tens of thousands of years to 400 million years.
The work was done by NASA Solar System Exploration Research Virtual Institute (SSERVI) researchers led by Principal Investigator Bill Bottke of the Institute for the Science of Exploration Targets (ISET) team at the Southwest Research Institute and included Tim Swindle, director of the University of Arizona's Lunar and Planetary Laboratory.
The inner Solar System's biggest known collision was the Moon-forming giant impact between a large protoplanet and the proto-Earth.
Evidence that the giant impact produced a large number of kilometer-sized fragments can be inferred from laboratory and numerical impact experiments, the ancient lunar impact record itself, and the numbers and sizes of fragments produced by major main belt asteroid collisions.
Numerical simulations of the giant impact indicate this event not only created a disk of debris near Earth that formed the Moon, but it also ejected huge amounts of debris completely out of the Earth-Moon system.By modeling the evolution of giant impact debris over time and fitting the results to ancient impact heat signatures in stony meteorites, the team was able to infer the Moon formed about 4.47 billion years ago, in agreement with many previous estimates.The most ancient Solar System materials found in meteorites are about one hundred million years older than this age.By linking studies of the Moon, of main belt asteroids, and of meteorites that fall to Earth, we gain a better understanding of the earliest history of our Solar System." Explore further: The abundance of water in asteroid fragments More information: "Dating the Moon-forming impact event with asteroidal meteorites," Science. This age has been determined with the radioactive dating technique.The fate of this material, comprising as much as several percent of an Earth mass, has not been closely examined until recently.However, it is likely some of it blasted main belt asteroids, with a record plausibly left behind in their near-surface rocks.Collisions on these asteroids in more recent times delivered these shocked remnants to Earth, which scientists have now used to date the age of the Moon.The research indicates numerous kilometer-sized fragments from the giant impact struck main belt asteroids at much higher velocities than typical main belt collisions, heating the surface and leaving behind a permanent record of the impact event."Here at LPL, we had been determining ages of impact events that affected meteorites, and when we got together, we found that our data matched his predictions," he added."It's a great example of taking advantage of groups that work in two different specialties - orbital dynamics and chronology - and combining their expertise." One possible realization of the Moon-forming impact event is animated.