Hard on the heels of learning that life-friendly planets orbiting young stars would quickly lose atmosphereand that it “now seems inevitable” that we’ll find life out there anyway, wew find out about the giant water worlds:
Using new data about the radii and mass of exoplanets collected by the Gaia space satellite, Harvard planetary scientist Li Zeng and his colleagues gather more details about the exoplanets’ internal structures.
They found that those big gas dwarfs are better explained as water worlds. But these are not water worlds like Earth, where despite covering 71 percent of the surface, water only accounts for 0.02 percent of Earth’s mass. Instead, these worlds are made of 25 percent and up to 50 percent water, with strange, vast oceans covering them. It’s possible that up to 35 percent of all known exoplanets are these vast ocean-covered orbs, Li noted at a conference last summer. Jason Daley, “One-Third of Exoplanets Could Be Water Worlds With Oceans Hundreds of Miles Deep” at Smithsonian Magazine
These are not “ocean planets.” Their surface temperatures are expected to bde in the 200 to 500-degree range and the oceans could be hundreds of miles deep: “Unfathomable. Bottomless. Very Deep,” a researcher told Gizmodo (quoted at Smithsonian). To say nothing of very high pressure.
The researchers think that the reason we don’t have these impressive but big-waste-of-water worlds in our own solar system is the gas giants: “In other star systems without a Jupiter-sized planet, the formation of rocky “super-Earths” and water worlds is probably pretty common.”
So, it turns out, even if there is lots of water in a solar system, that doesn’t add up to habitability either. Talk about Rare Earth and Privileged Planet.
See also: Researchers: Most life-friendly planets orbiting young stars would quickly lose atmosphere from their results: More dramatically, the results of this study imply that for planets orbiting M-dwarf, the planets can only form Earth-like atmospheres and surfaces after the activity levels of the stars decrease, which can take up to several billion years. More likely is that many of the planets orbiting M-dwarf stars to have very thin or possible no atmospheres. In both cases, life forming in such systems appears less likely than previously believed.
Researcher: Why finding extraterrestrial life “now seems inevitable,” maybe soon. He ends with, “The ancient question ‘Are we alone?’ has graduated from being a philosophical musing to a testable hypothesis. We should be prepared for an answer.” It’s worth asking another question: What if, after decades of research, no answer comes? What would that change?
Faint hopes easily revived: Life may be evolving on closest exoplanet
Forbes cosmology commentator: Maybe we ARE alone
Still no space aliens? That’s because they are keeping us in a zoo!
and
Tales of an invented god