Article written by: Gavin Ramsay, resident Astronomer in the Armagh Observatory and Planetarium
The discovery of planets orbiting around other stars has been one of humankinds greatest achievements. The existance of these ‘exo-planets’ can challenge our perception of our place in the universe. Since the first confirmed detection of a planet around another normal star (51 Peg) in 1995, many thousands of planets have been discovered. Indeed, it is likely that most stars will have their own system of planets. It is important in answering the question – is there intelligent life out there?
With the discovery of exo-planets, astronomers then began to wonder whether these distant planets have moons, just like our Moon and Jupiter and Saturn – which currently have 79 and 62 known moons apiece. However, discovering ‘exo-moons’ around exo-planets is an extremely challenging task.
A pair of Columbia University astronomers using NASA’s Hubble Space Telescope and Kepler Space Telescope have assembled compelling evidence for the existence of a moon orbiting a gas-giant planet 8,000 light-years away. The image is an artist’s impression of what the system might look like. Image Courtesy of Dan Durda and Columbia News
Exo-planets can initially be discovered when they are aligned ...