A wrong tilt could freeze Earth-like worlds into “snowballs”. Thus, making their oceans freeze and surface life impossible.
A team of researchers from the University of Washington conducted a new study. So, they found the axial tilt and orbital dynamics of planets in the habitable zone around stars like our own sun can lead to “snowball states,” which are essentially extreme ice ages.
The new study also shows that planets which orbit in the “habitable zone” don’t necessarily support life as we know.
The study’s lead author, Russell Deitrick along with his team learned that a planet’s obliquity, or the angle at which a planet’s rotation axis tilts, and its orbital eccentricity, a parameter that determines the amount that an orbit deviates from a perfect circle might affect its potential for life.
They limited their study to planets orbiting in the habitable zones of “G dwarf” stars, or those like the sun.
Sorting out a Previous Idea
So, the new study helps sort out conflicting ideas proposed in the past.
Previous research suggested that planets in the habitable zone of sun-like stars having an extreme axial tilt would be warmer. However, the new research team debunked this theory.
“We found that planets in the habitable zone could abruptly enter ‘snowball’ states if the eccentricity or the semi-major axis variations — changes in the distance between a planet and star over an orbit — were large or if the planet’s obliquity increased beyond 35 degrees,” Russell Deitrick said in a statement.
The axial tilt of the Earth, luckily, varies relatively slightly. Thereby making it “a relatively calm planet, climate-wise,” co-author Rory Barnes, an astronomer at UW, said in the statement.
Referring to the exoplanets, Mr. Barnes said: “ice ages on exoplanets can be much more severe than on Earth, that orbital dynamics can be a major driver of habitability and that the habitable zone is insufficient to characterize a planet’s habitability.”
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