In all the time scientists have been looking at planets in other solar systems, they’ve never found a moon. Now, for the first time, they’ve found the next best thing—a cloud of dust near a planet that might one day form a moon. Or three, as it turns out.
Scientists discovered the dust cloud near a (relatively) young exoplanet in a star system dubbed PDS 70 located 370 lightyears from Earth. It’s a discovery years in the making. The team first found a gas giant protoplanet (PDS 70b) in 2018 using the European Southern Observatory’s Very Large Telescope (yes, that’s the actual name of the telescope) in Chile. It followed that initial discovery with another young gas giant (PDS 70c) in the same system using the same telescope.
Scientists believe both gas giants are ten times larger than Jupiter and that the system is about ten million years old. The planets themselves are young, with one not even fully formed. We’re seeing images that originated 370 years ago (give or take), of course, but that’s a heartbeat in the cosmic scheme of things.
Given that it already looked like an interesting system, scientists took a “look” with all other instruments possible, including the Atacama Large Millimeter/submillimeter Array (ALMA). That array comprises 66 shortwave radio dishes and made it possible to see the potential moon-forming cloud. That cloud is near PDS 70c (the young gas giant), and current spans a distance slightly wider than space between the Earth and Sun.
Altogether, the dust cloud has enough mass to form up to three moons comparable to Earth’s Moon. It’s possible moons have already formed in the area, but the ALMA isn’t sensitive enough to see. But, when Extremely Large Telescope (again, yes, that’s actually the name) is built, it might have the power to confirm the presence of moons. Or, you know, a space station.