Hot super-Earths could host life after all (New Scientist) (it’s a July story; I found it through a blog that linked to my Watchmen smiley):
Massive, rocky worlds called ‘super-Earths’ – even those orbiting searingly close to their stars – may provide the right conditions for life, recent research suggests.
Super-Earths orbiting close to their stars, for example, experience gravitational tugs that keep them ‘tidally locked’ to their hosts. That means one side of such a planet always faces its star, the way the Moon always shows the same side to Earth.
Astronomers previously assumed such planets would be two-faced worlds of fire and ice, with one half molten and the other frozen.
But new models show that if a tidally locked super-Earth has an atmosphere at least as dense as Earth’s, strong winds could transport heat from its hot side to its cold side. Similarly, if the planet has a global ocean, its currents could help spread the warmth.
This effect still wouldn’t offset the intense heat the planets would experience at close distances to Sun-like stars. But it means super-Earths could potentially host life as close as 0.05 astronomical units away from dim stars known as red dwarfs, which make up about 85% of the stars in the galaxy (for comparison, Mercury lies 0.38 AU away from the Sun).
And in some ways, super-Earths might even be more likely to support life than their Earth-sized cousins, scientists say.
Recent research suggests that super-Earths will experience more plate tectonic activity than smaller rocky worlds.
On Earth, plate tectonics – the shifting and colliding of continental plates – is necessary for life.Super-Earths should have larger molten cores and should generate more heat than Earth-sized worlds, Valencia told New Scientist. This could cause more vigorous convection in the planets’ mantles and create thinner plates that slip and slide more easily.
So, let’s recap: a terrestrial planet 15 times more massive than the Earth, orbiting a dim red star, with a large molten core and stronger tectonic activity… that sounds a lot like Krypton. No wonder they call them Super Earths. Does one of the life forms on such a world proclaim unheeded prophecies of doom, while building a space craft to rescue its son from the dying planet?