The Hunt for the Moons of Exoplanets
New telescopes promise to reveal countless moons scattered across the galaxy
Back in 2017, a pair of astronomers made an announcement. They’d found a moon, they said, and not just any old moon: this was a moon as big as Neptune, locked in orbit around a far distant planet. If true it would be the largest moon ever found, and the first to be seen beyond our solar system.
Yet the announcement came with a caveat. The data behind the potential discovery was weak, and a giant moon was not the only possibility. It was instead, the astronomers said, better described as a candidate moon, and though the evidence hinting at it was tantalising, it was also inconclusive.
Follow up studies cast more doubt. A team in Germany, reanalysing the data, said the signal could be coming from a hidden planet instead. But they too were uncertain in their result, arguing less that it was a planet and more that the possibility could not be ignored. The first study, they implied, was hasty in jumping to the idea of an alien moon.
Another team, this time at Harvard, saw no signs of anything unusual — moon or planet — at all. The signal, they wrote, was likely a data processing error. Since none of these possibilities can be eliminated, the existence of the exomoon remains in doubt…
