Article by: Andacs Robert Eugen, on 30 October 2022, at 10:38 am PDT

A recent study presents an unexpected conclusion about the number of Earth-like exoplanets.

Following a simulation, the researchers were able to estimate the number of planets in other solar systems that have a similar composition to Earth, that is, the same ratio of continents to oceans.

According to them, only 1% of telluric (rocky) exoplanets in the circumstellar habitable zone resemble Earth.

In contrast, most potentially life-bearing planets have very little surface water, being dominated by land-about 80% of the estimated number. About 20% of exoplanets are almost completely covered by oceans, and a relatively balanced ratio between land and water (1:3) exists in only 1% of cases.

Therefore, our planet is a truly rare one in the Universe. The researchers state that exoplanets would be very different from our Earth, even if there were alien life forms. Thus, the oceanic planets would have a very warm, tropical climate, while the mainly land-dominated planets would be much colder, covered in frozen desserts.

The ratio between water and land is determined by the geological activity of the planet (which produces earthquakes, and volcanic eruptions, but also the formation of mountains and land areas), and this is in turn influenced by the temperature of the planet's mantle.

In the case of Earth, the conditions that determined the ratio of water to land stabilized about 2.5 billion years ago. The conclusion of the study was presented at the European Science Congress, which took place in Granada, Spain, in September.