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Objects Destabilized by Jupiter or Saturn May Have First Brought Water to Earth

Gas giants forming in the early moments of our solar system may have propelled so-called planetesimals in the asteroid belt toward Earth, carrying water with them.

A model of how our solar system could have looked early in its formation. At left is the young sun (a protosun), with particles of gas (the nebula) and chunks of rock (the planetesimals) nearby. This zone is approximately where the inner solar system exists today. Most of the water in the solar system lay beyond the "frost line." | University of Hawaii Institute for Astronomy