Carl Sagan enjoyed talking about “star stuff” and reminding us that we—and everything else in the cosmos—is made of it. “Star stuff” is really a synonym for stardust, which doesn’t sound quite as romantic, given the dust part. Regardless of what you call it, new findings show that stardust is even more enchanted and important than previously thought: it contains water.
A team of scientists from California’s Lawrence Livermore National Laboratory wanted to investigate the much-debated question of where water comes from (it doesn’t just come from clouds, it turns out—that’s just what we Earthlings might think) and whether solar wind can produce it. They did what researchers before them have done, which is to simulate the chemical reaction that occurs when tiny grains of dust floating around in the cosmos are blasted with solar wind. Such experiments have before revealed that this dust does contain organic compounds such as carbon, but this time when the team trained their ultra-awesome microscopes on these specks of desk, they found something else, water. The study, published in the Proceedings of the National Academy of Sciences of the United States of America, details the first time scientists have found water inside stardust.
The experiment demonstrates how the water might form in the specks, which are made of silicates. Charged particles of the solar wind, including hydrogen ions, collide with the oxygen in the silicates and make water. The finding sheds light on how planetary bodies that don’t have air, such as asteroids or the moon, can have water. It also may explain how water first gets to planets like Earth, although one member of the team was careful to point out that they’re not drawing the conclusion that these dust specks account for the amount of water that exists in all of our oceans. It’s more likely that water-rich asteroids brought such volumes of water to our planet in one fell swoop. The ESA’s Rosetta spacecraft, which woke up right on schedule on Monday, should also provide some information about whether comets could have contributed to the water on earth.
The implications of this study are huge. Stardust is all over the place (not just in our solar system), and given that it contains both carbon and water, the two essential building blocks for life as we know it, it’s even more likely that life exists throughout the universe. This means that stardust really does make life, and that it may very well be raining down the essential elements of life on planets throughout the galaxy. Of course, someday we’ll learn that non-carbon-based life forms exist somewhere out there, but for now, all we can do is keep looking.