Looking for life in our universe by chance alone takes us to the amusement park.
A fluctuating tilt in a planet’s orbit does not preclude the possibility of life, according to new research by astronomers at the University of Washington, Utah’s Weber State University and NASA. In fact, sometimes it helps.
That’s because such “tilt-a-worlds,” as astronomers sometimes call them—turned from their orbital plane by the influence of companion planets—are less likely than fixed-spin planets to freeze over, as heat from their host star is more evenly distributed.
This happens only at the outer edge of a star’s habitable zone, the swath of space around it where rocky worlds could maintain liquid water at their surface, a necessary condition for life. Further out, a “snowball state” of global ice becomes inevitable, and life impossible.
This computer-simulation-guided thought increases the habitable zone by 10 to 20%.
Their findings also argue against the long-held view among astronomers and astrobiologists that a planet needs the stabilizing influence of a large moon—as Earth has—to have a chance at hosting life.
“We’re finding that planets don’t have to have a stable tilt to be habitable,” Barnes said. Minus the moon, he said, Earth’s tilt, now at a fairly stable 23.5 degrees, might increase by 10 degrees or so. Climates might fluctuate, but life would still be possible.
The moon, the researchers claim, could actually be a disadvantage.
Good thing They have called back and are now barrelling to Earth at warp speed.
Paper here (open access).
How did we get to this amusement park anyway? Here’s a partial explanation: How do we grapple with the idea that ET might not be out there?
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