When searching for Earth-like worlds around other stars, rather than searching for the “faint blue dot” described by Carl Sagan, new research suggests that searching for dry, cool “faint yellow dots” may have a better chance of success. The close balance between land and water that helped life thrive on Earth may be very unusual, according to a Swiss-German study presented at the 2022 Europlanet Science Conference in Granada.
Tilman Spoon and Dennis Hoeing studied how the evolution and cycles of continents and waters could shape the evolution of terrestrial exoplanets. Their model results suggest that the probability that planets are covered by Earth is about 80%, with 20% likely that they are primarily oceanic worlds. Barely 1% of the results had an earth-like distribution of land and water.
“We earthlings enjoy a balance between Earth areas and oceans on our planet. “It is tempting to assume that a second Earth will be just like our own, but our modeling results suggest that this is unlikely to be the case,” said Professor Spoon, executive director of the International Institute for Space Sciences in Bern, Switzerland.
The team’s numerical models indicate that average surface temperatures won’t be very different, perhaps with a difference of 5 degrees Celsius, but the distribution from land to ocean will influence planetary climates. The ocean world, with less than 10% of Earth, is likely to be humid and warm, with a climate similar to Earth in the tropical and subtropical era that followed the asteroid impact that caused the extinction of the dinosaurs.
Continental worlds, containing less than 30% of the oceans, will have cooler, drier, and harsher climates. Cold deserts may occupy the interior of land masses, and in general will resemble our Earth sometime during the last Ice Age, when glaciers and ice sheets developed.
Continents grow on Earth volcanic activity Its erosion by weathering is roughly balanced. Photosynthesis-based life thrives on Earth, where it has direct access to solar energy. The oceans provide a huge reservoir of water that enhances precipitation and prevents the current climate from becoming too dry.
In Earth’s drive tectonic plates, internal heat leads to geological activity, such as earthquakes, volcanoes, and mountain formation, and leads to the growth of continents. Earth erosion is part of a series of cycles that exchange water between the atmosphere and the interior. our Numerical models How these cycles interact shows that today’s Earth may be an extraordinary planet, and that Earth’s mass balance may be unstable over billions of years. While all the planets that have been designed can be considered habitable, their animals and plants may be very different.”
Conference summary: meetingorganizer.copernicus.or… 22 / EPSC2022-506.html
Submitted by the European Astrobiological Network Society
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