Astronomers have pinpointed what appears to be the first moon detected outside our solar system, a large gaseous world the size of Neptune that is unlike any other known moon and orbits a gas planet much more massive than Jupiter.
The discovery, detailed by researchers on Wednesday, was a surprise, and not because it showed that moons exist elsewhere – they felt it was only a matter of time for one to be found in another star system. They were amazed instead by how different this moon was from the roughly 180 known in our solar system.
“It’s big and weird by solar system standards,” Columbia University astronomy professor David Kipping said of the moon, known as an exomoon because it is outside our solar system.
Our solar system’s moons all are rocky or icy objects. The newly discovered exomoon and the planet it orbits, estimated to be several times the mass of our solar system’s largest planet Jupiter, are both gaseous, an unexpected pairing. They are located 8,000 light years from Earth.
Kipping and study co-author Alex Teachey, a Columbia graduate student, said their observations using NASA’s Hubble Space Telescope and Kepler Space Telescope provided the first clear evidence…
