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.
Exoplanets
At New Scientist: We’ll soon find out for sure if aliens are out there
Of course, they’re out there and as long as there’s an Out There, they’ll always be out there.
Researchers: Earth may not be the most life-friendly planet
Their computer model might seem more convincing if a single extraterrestrial life form of any sort had ever been found.
Rob Sheldon: Don’t give up all ET hope due to recent exoplanet disappointment
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.
Bad news about life on rocky alien planets
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.
How many Earth-like planets are there?
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: Toxic gases would slow emergence of life on exoplanets
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.
Researchers: What’s INSIDE a planet determines habitability
The elemental building blocks are universal; their abundance is not.
Rob Sheldon: That “sterile exoplanet ocean” paper is bunk!
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?
Doubt cast on new “exomoon” Rob Sheldon explains
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.
Exoplanets: Those water worlds would have sterile oceans too…
Researchers: An all-ocean planet would be sterile due to lack of nutrients leached from land.
Recent finding: The “water world” exoplanets are not habitable ocean planets
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.
Researchers: Most life-friendly planets orbiting young stars would quickly lose atmosphere
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.
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
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.