NASA Scientists Make 'Exciting' Discovery About Alien Worlds

NASA scientists may have just discovered how planets are made by using the James Webb Space Telescope.

The discovery—presented in a study published in the Astrophysical Journal Letters—was made by observing water vapor from protoplanetary disks. The latter is a rotating pattern of gas and dust that follows the formation of a new star.

The telescope revealed that cold pebbles in the outer region of the disks, carried by friction and gas, drift inside towards the newly formed star, a NASA press release detailing the findings revealed on Wednesday. When these icy pebbles drift towards the warmer region—dubbed the "snowline"—water vapor is released. This physical process gradually delivers both water and solids to surrounding planets.

There have been theories of this process before, but this is the first time the Webb telescope has actually documented it taking place.

"In the past, we had this very static picture of planet formation, almost like there were these isolated zones that planets formed out of," team member of the project, Colette Salyk of Vassar College in Poughkeepsie, New York, said in the press release. "Now we actually have evidence that these zones can interact with each other. It's also something that is proposed to have happened in our solar system."

"Webb finally revealed the connection between water vapor in the inner disk and the drift of icy pebbles from the outer disk," added principal investigator Andrea Banzatti of Texas State University, in San Marcos. "This finding opens up exciting prospects for studying rocky planet formation with Webb!"

To reach these findings, astronomers used the Mid-Infrared Instrument in the Webb telescope to observe four disks—"two compact and two extended"—that circle two stars. These stars are between 2 and 3 million years old—which, in the context of cosmic time, is very young.

The compact disks were found to release more water than the extended ones. This is because there was a more efficient pebble drift. These icy pebbles were carried to a distance equivalent to Neptune's orbit, according to NASA. In short, the compact disks are more efficient at distributing the elements necessary to planet formation than extended ones.

When the findings were first recorded, astronomers were confused.

"For two months, we were stuck on these preliminary results that were telling us that the compact disks had colder water, and the large disks had hotter water overall," Banzatti said. "This made no sense, because we had selected a sample of stars with very similar temperatures."

A closer look at the data revealed why this was. The compact disks had extra cool water inside the snowline.

"Now we finally see unambiguously that it is the colder water that has an excess," Banzatti said. "This is unprecedented and entirely due to Webb's higher resolving power!"

Basically, it is cold water that contributes more effectively to rocky planet formation.

The James Webb Space Telescope is a NASA space telescope that conducts infrared astronomy. It was launched in 2021, and is the largest optical telescope in space.

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