Astronomers in the United Kingdom say they have discovered a planetary system that is similar to our own, orbiting more than 5,000 light-years from Earth.

Researchers at St. Andrews University found two planets that are close matches for Jupiter and Saturn orbiting a star about half the size of the sun.

Martin Dominik, a Royal Society University Research Fellow at the university's school of Physics and Astronomy, presented the finding at the Royal Astronomical Society's National Astronomy Meeting in Belfast last week.  

Dominik told CBC News Monday the newly discovered system, orbiting star OGLE-2006-BLG-109L, "looks like a scaled-down version of the solar system."

"While the masses of the planets are roughly the same as those of Jupiter and Saturn, their host star is half as massive as the sun, and both the orbital radii and periods are half of those of Jupiter and Saturn, respectively," he said.

The system was discovered using a technique called gravitational microlensing, which exposes new planets by observing the brightening of a known star when gravity bends light from an unseen star. The process is not sensitive to the size of the planet, just the mass. This technique is biased against detecting something that roughly resembles the solar system.

Dominik said it is "quite plausible" that this new system formed in a similar way as the solar system, and "therefore it might well host rocky inner planets like Earth that might harbour life."

However, he said, because of the system's distance from Earth, researchers will probably never know for sure.

"Nevertheless," he said, "the sheer existence of this system lets us think that there are many other similar systems out there." 

He said that in order to estimate the presence of life in the universe, it is "essential" to know whether the solar system is unique.

Additionally, Dominik said the finding "makes a strong case" that planetary systems, rather than lonely planets, are the rule.

Such a realization was "not really expected," he said, because only 10 per cent of the planets detected outside the solar system so far have "family and friends," or nearby planets.

With files from Jennifer Wilson