Miniature Earth-like Solar System Found
Our Solar System may not be as unique as previously thought, Professors Andrew Gould and Scott Gaudi of the Ohio State University say. The newly discovered gaseous planets, OGLE-2006-BLG-109Lb and OGLE-2006-BLG-109Lc, are about 5,000 light-years away from Earth, orbiting a star about half the size of the sun and are found to have 71 and 27 percent the mass of Jupiter. Discovered using gravitational lensing, which bends light from a distant object by the gravity of a foreground object (in this case, another star), these planets display many interesting similarities with our own Solar System. The Gaudi-led consortium has found that the ratio of the each planet’s masses is about 3:1 (3.33:1 for Jupiter/Saturn), the distance between each of the planets is roughly twice the distance between the Earth and the Sun, and temperatures are about 30 percent cooler than that of Jupiter and Saturn.
Because this system is so similar to our own, it raises an interesting question: just how unique is our solar system? Previous planets discovered around other stars have been shown to be very odd when compared to our own; however, this new discovery effectively represents a scaled-down version of our own Solar System. Astronomers may be able to use it to study whether the process which formed our solar system is more common than previously assumed.
The theory behind planet formation is heavily dependant on the temperature of a system. The temperature of a planetary system dictates exactly how much material is present to form the planets. Higher temperatures means material can be easily blown away by radiation, while lower temperatures mean planets form much closer to the parent star. If current planetary formation theories are correct, two systems should have formed in roughly the same manner if they had roughly the same characteristics, including the temperature on each planet.
About 250 planets and 25 multi-planet systems have been discovered to date. Of these, only one has been found to contain a rocky planet similar to Earth. However, this new system provides astronomers with the first bit of evidence to say that we are not so unique in the galaxy. In fact, it is plausible to say that perhaps the chances of an Earth-like planet forming in our galaxy are much higher than previously thought.
Discovering these Earth-like planets, however, is much more difficult than finding Jupiter/Saturn-like planets; current methods for detecting these planets are very sensitive to the mass of the planets. Higher mass, gaseous planets affect their parent star more than their low mass, rocky counterparts; we observe this effect through telescopes. In order to find these low mass planets, bigger telescopes with much higher resolution than what is currently available must be built. The next generation of ground and space telescopes - such as the Large Binocular Telescope, the Giant Magellan Telescope, the James Webb Space Telescope - will be the first telescopes big enough to begin to discover these planets. If the odds of an Earth-like planet forming in our galaxy are much higher, as the evidence from this newly discovered planetary system suggests, it is only a matter of time until we discover an elusive twin to our own Solar System.
