#astrochemist

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Over the past three decades, van Dishoeck has traced water to its cosmic origin. H2O molecules are older, her findings indicate, than the sun. Through a combination of theoretical chemistry, telescope observations and laboratory experiments at Leiden University, van Dishoeck and her collaborators and colleagues have established that water originated in the interstellar cloud of gas and dust that, 4.5 billion years ago, gravitationally collapsed to form our solar system. In that ancient cloud, ice accumulated on the surfaces of dust grains as they bumped into hydrogen and oxygen atoms that found each other and bonded in the surrounding gas.

“All the water that we see here on Earth, all the [water] molecules that we have in our bodies,” van Dishoeck said, “were already formed on the surfaces of the grains in the cloud out of which our solar system collapsed.”

In other words, not only is water essential for life on a planet, it helps planets grow in the first place. Van Dishoeck and her colleagues have observed signatures of abundant ice in distant interstellar clouds, suggesting the story repeats itself throughout the cosmos. Watery worlds might not be rare.