Two Columbia University researchers Alex Teachey and David Kipping may have found the first moon outside our solar system, potentially about the size of Neptune or Uranus, reported AP. The so-called exomoon is considerably larger than our solar system’s biggest moon. Jupiter’s moon Ganymede has a diameter of about 3,270 miles (5,260 km). The exomoon is estimated to have a diameter of about 30,600 miles (49,000 km).
The newly discovered exomoon and the planet it orbits, are both gaseous, and located 8,000 light years from Earth, according to a Reuters report.
The team behind this intriguing discovery evaluated more than 250 planets outside our solar system which had been discovered by NASA’s Kepler Space Telescope. Out of these, only one planet showed signs The Columbia astronomers directed the Hubble Space Telescope in October in an attempt to verify or rule out their findings. Since they were on a lookout for a second temporary dimming of starlight, the team did a 40-hour observation on the Hubble Space Telescope to investigate further. The first dip in brightness would be the planet crossing in front of its star while the second dip could possibly substantiate their extraordinary claim of exomoon outside our solar system.
The powerful Hubble telescope did detect the second decrease in starlight three and a half hours after the first dip. However, the observation period was over before the moon could complete its transit. Another compelling evidence in favour of their apparent discovery was that the planet passed in front of its star one hour earlier than they had predicted.
Despite the evidence, Teachey and his colleague Kipping need another look with Hubble, which will happen only in May 2019. In the meantime, they are encouraging other researchers and astronomers to join in as the subject offers insight into how rare our solar system is.
“The first exomoon is obviously an extraordinary claim and it requires extraordinary evidence,” Teachey told AP. “Furthermore, the size we’ve calculated for this moon, about the size of Neptune, has hardly been anticipated and so that, too, is a reason to be careful here.”, he added.
Our own solar system has close to 200 moons. Out of the eight planets, only Mercury and Venus have none.
Given the conditions that both the planet and its potential moon are gas giants, it cannot be said that this planet might support life. “But going forward, I think we’re opening the doors to finding worlds like that,” Teachey told AP.