Most exoplanets, we are told, fall into this size range and it is not yet known if it has a rocky surface, considered important for life. Here’s a roundup of some things we know.
Of course, they’re out there and as long as there’s an Out There, they’ll always be out there.
Their computer model might seem more convincing if a single extraterrestrial life form of any sort had ever been found.
Sheldon: … in our own solar system, Saturn is far outside the “Goldilocks Zone” yet it has a moon, Enceladus, that is emitting steam jets filled with hydrocarbons. … The danger of being overly-quantitative is not just the overreliance on models, or the higher risk of failure, but rather the real probability that “certainty” blinds one from observing the actual phenomenon.
Kreidberg’s team estimated that the promising planet had temperatures of –273 degrees Celsius on the night side and 767 degrees C on the day side, which implies little or no atmosphere to moderate it.
Claim: ” Based on their simulations, the researchers estimate that planets very close to Earth in size, from three-quarters to one-and-a-half times the size of earth, with orbital periods ranging from 237 to 500 days, occur around approximately one in four stars.”
Researchers: The habitable zone for complex life around many stars could be much smaller than previously thought once the concentrations of carbon monoxide and carbon dioxide on planets is considered.
The elemental building blocks are universal; their abundance is not.
The amazing thing about life, is that it is always so very adaptable. Who knew that bugs can live at 140C, or with metabolism so slow it takes centuries to replicate?
Sheldon: There are red flags all over this data, but the investigators are standing by their measurement. This is what irreproducible papers look like in physics, and why the same crisis that afflicts other disciplines also afflicts physics.
Researchers: An all-ocean planet would be sterile due to lack of nutrients leached from land.
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.
From their results: 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.
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?
The fundamental problem is still the same: It is very difficult to extrapolate from a sample of one instance of life. Suppose we had information on tens of thousands of exoplanets, thousands of which had life. Making the reasonable assumption that a pattern develops within this data, we could then give fairly reliable odds on a given planet having life if its relevant data are known. But we don’t have any of this. It’s all a dreamscape.