You might assume that there has always been water on Earth, that water was there from the very beginning, when our planet was formed. But scientists increasingly think that water on Earth may have originated elsewhere and been carried here by comets. However, the water from comets had to come from somewhere, and astronomers recently made a discovery that could shed light on how that water was found in the solar system.
The researchers used the Atacama Large Millimeter/submillimeter Array (ALMA), an array of radio telescopes in Chile, to study a planet-forming disk around the star V883 Orionis, searching for water there to see how it would be transported as the disk evolves. on planets
They were able to compare two different types of water, the one with one oxygen atom and two hydrogen atoms that we know well, and the other, which is a heavier type of water that has one oxygen, one hydrogen, and one deuterium (a stable isotope hydrogen) atom. These types of water form differently, so scientists can use the ratio of normal to heavy water as a fingerprint to see how old the water is and where it came from.
This is important because the water in the disk of V883 Orionis has similar properties to the water seen in our solar system. “V883 Orionis is the missing link in this case,” Principal Investigator John J. Tobin of the National Radio Astronomy Observatory said in a statement.
“The composition of the water in the disk is very similar to that of comets in our own solar system. This is confirmation of the idea that water in planetary systems formed billions of years ago, before the sun, in interstellar space, and has been inherited by both comets and Earth relatively unchanged. ”.
This evidence suggests that the water was in the region of space that would become the solar system before the planets and stars formed. “We can now trace the origins of water in our Solar System before the formation of the sun,” Tobin said.
Next, the researchers want to use the upcoming Extremely Large Telescope to search for other planet-forming disks and see how water moves through the disks as planets form.
The research is published in the journal Nature.