Astronomers have detected water vapor in the inner region of a protoplanetary disk – where rocky planets may be forming – for the first time, thanks to the James Webb Space Telescope.

Located 370 light years away, PDS 70, a K-type star, is surrounded by a giant hot swirling jumble of gas. This protoplanetary disk is separated into two parts by a gap five billion miles (eight billion kilometers) wide – a telltale sign that material is coalescing to create new worlds. Scientists believe two gas giants are forming in that gap. They also say they have spotted water vapor in the disk’s inner area before the gap, where rocky terrestrial planets may be being born. Protoplantary disk rendering

Epic: Artist’s impression of the PDS 70 star; its inner protoplanetary disk where rocky worlds may be forming; a large gap in which two or more gas planets may be coming together; and the outer protoplanetary disk … Credit: NASA, ESA, CSA, J. Olmsted (STScI)

“We’ve seen water in other disks, but not so close in and in a system where planets are currently assembling. We couldn’t make this type of measurement before Webb,” said Giulia Perotti, a postdoc fellow at the Max Planck Institute for Astronomy in Germany and lead author of research into PDS 70 and its planet-forming disk, published in Nature on Monday.

It’s the first time scientists have managed to detect water vapor in the terrestrial zone of a protoplanetary disk. The findings suggest that if rocky planets are forming around PDS 70, they could have direct access to water, giving astronomers a glimpse into how Earth may have formed.