Researchers at Ohio State University have recently concluded that around 15 percent of all stars in our galaxy could host solar systems. Our galaxy is estimated to contain between 100 and 400 billion stars, so the study would suggest the presence of over 100 million solar systems, like our own, in the Milky Way.
The study made use of a technique called “gravitational microlensing,” to extrapolate the figure. Basically stated, light rays in space are bent by the gravity of a massive object, such as a star. When a planet passes in front of a star and our line of sight, the planet’s gravity will act like a lens and focus the light rays, causing a short term increase in brightness and altering the apparent position of the star. It is this “gravitational microlensing effect,” which astronomers then use to find objects that emit no light, such as planets.
“Now we know our place in the Universe. Solar systems like our own are not rare, but we’re not in the majority, either,” said Scott Gaudi, astronomer at the Ohio State University.
In separate research, over 400 extrasolar planets have been detected orbiting around 300 stars, thus far. Most of the planets discovered, however, are massive and quite likely gas giants, like Jupiter or Saturn. Astronomers are keen to discover more smaller Earth like planets, composed of rock and metals, as these are more likely able to support life.