A new study has revealed that planets outside our solar system are likelier to have liquid water and be more habitable than we previously thought.
Astrophysicist Jeremy Leconte at the University of Toronto said that planets with potential oceans could have a climate that is much more similar to Earth’s than previously expected.
Scientists have thought that exoplanets behave in a manner contrary to that of Earth, that is, they always show their same side to their star. If so, exoplanets would rotate in sync with their star so that there is always one hemisphere facing it while the other hemisphere is in perpetual cold darkness.
Leconte’s study suggests, however, that as exoplanets rotate around their stars, they spin at such a speed as to exhibit a day-night cycle similar to Earth.
Leconte added that there is no permanent, cold night side on exoplanets causing water to remain trapped in a gigantic ice sheet. Whether this new understanding of exoplanets’ climate increases the ability of these planets to develop life remains an open question.
Researchers reached their conclusions via a three-dimensional climate model they developed to predict the effect of a given planet’s atmosphere on the speed of its rotation, which results in changes to its climate.
Leconte noted that atmosphere is a key factor affecting a planet’s spin, the impact of which can be of enough significance to overcome synchronous rotation and put a planet in a day-night cycle.
Leconte explained that the Moon always shows its same side, because the tides raised by Earth create a friction that alters its spin and the Moon is in synchronous rotation with Earth because the time it takes to spin once on its axis equals the time it takes for it to orbit around Earth. That is why there is a dark side of the moon, but the tidal theory neglects the effects of an atmosphere.
The study is published in Science Express.
—ANI