Astronomers may have detected the first moon outside the solar system, around 8,000 light years from Earth, Reuters reported on Thursday. It is reportedly as big as Neptune and orbits a planet the size of Jupiter. Such natural moons that orbit planets outside the solar system are called exomoons. None have been confirmed so far even though more than 3,500 exoplanets are known.
The celestial object is “big and weird by solar system standards”, said Columbia University astronomy professor David Kipping. It is gaseous and orbits a gas planet 10 times the mass of Jupiter. Moons in the solar system are either rocky or icy.
Kipping and co-author Alex Teachey, a student at Columbia, published the results of their discovery on Wednesday. They will use the Hubble Space Telescope for more observations in May 2019 to confirm their finding.
The celestial object has a diameter of about 49,000 km, more than nine times the size of Jupiter’s Ganymede, which is the largest moon in the solar system. Its planet orbits Kepler-1625, a star 70% larger than the sun. The object has a mass about 1.5% that of the planet – a similar mass-ratio as the Earth and moon.
Researchers detect exoplanets by observing the reduction in the brightness of the star they orbit. This occurs when the exoplanet passes in front of the star, and the method is therefore called the “transit method”. The celestial body and its planet were also discovered using this method.
Limited-time offer: Big stories, small price. Keep independent media alive. Become a Scroll member today!
Our journalism is for everyone. But you can get special privileges by buying an annual Scroll Membership. Sign up today!