A second simulation followed Mercury's jettisoned particles through space. The bits, Horner says, would have traveled for millions of years.
"Mercury particles would've ended up on everything in the solar system," he said.
Some particles were swept up by Jupiter's gravity and flung from our solar system. Some landed on Earth.
Most would have gone to Venus. "It's the nearest stop,'' Horner said.
Exactly where they ended up was heavily influenced by where Mercury may have been at the time of the collision and exactly where the planet was hit, the simulations found.
The simulations determined that the particles wouldn't have fallen back to Mercury.
Because of the distance the particles would have been flung during the collision, it would have taken four million years for 50 percent of the particles to fall back to Mercury. By then, they would have already been carried away by solar radiation.
John Chambers, a research astronomer with the Carnegie Institution in Washington, D.C., agreed that Mercury bits may have landed on Earth.
"If Mercury was hit, especially by something big, pieces could have escaped and hit other planets,'' he said.
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