UK astronomers have helped discover the best example yet of a solar system like our own. It contains two giant planets resembling smaller versions of our own Jupiter and Saturn.
Space scientists are excited because the find suggests once again that solar systems just like the Sun’s are common throughout the galaxy.
We have reported before on previous such discoveries.
The latest find was made due to a fluke of nature. The two planets lie nearly 5,000 light years away but were revealed by a natural magnifying glass in space.
The star they orbit passed in front of a more distant star and magnified its light by 500 times – a phenomenon called gravitational microlensing.
The event was spotted using a technique called OGLE – the Optical Gravitational Lensing Experiment, For two weeks in early 2006, this dramatic example of the phenomenon was observed from observatories around the world.
They included scientists from universities in Manchester, Exeter, Liverpool, St Andrews, Scotland, and Oxford. As Professor Andrew Gould, of Ohio State University, studied the light beam, he spotted two blips – distortions that were caused by the two planets.
It is the third time a Jupiter-sized planet has been found by microlensing. The new solar system has been labelled OGLE-2006-BLG-109L.
Dr Martin Dominik, of the University of St Andrews, said: “While most planetary systems around other stars substantially differ from the solar system, a series of recent detections have brought us closer and closer to home. Sooner rather than later, someone can be expected to discover an Earth-mass planet orbiting a star other than the Sun – and it could be us.”
Colleague Professor Keith Horne, of St Andrews, added: “Once we know that planets similar to Earth are common, it is straightforward to go ahead on finding them and investigating whether these harbour any forms of life.”
Scott Gaudi, of Ohio State, said: “This is the first time we had a high-enough magnification event where we had significant sensitivity to a second planet – and we found one. You could call it luck, but I think it might just mean that these systems are common throughout our galaxy.”
The smaller planet is roughly twice as far from its parent star as the larger one, just as Saturn is roughly twice as far away from the sun as Jupiter.
Astronomers say microlensing could soon help them directly to detect planets as small as the Earth.
Picture credit: KASI/CBNU/ARCSEC