Chipping away at the millions of habitable exoplanets…

_{Denyse O'Leary

December 20, 2019

Exoplanets, Extraterrestrial life}

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In this new study, NYUAD Center for Space Science Research Scientist Dimitra Atri found that not all exoplanets in habitable zones will be able to maintain hospitable conditions for life. Exoplanets in close proximity to stars are subject to radiation bursts which can disrupt habitable conditions unless the exoplanet has significant atmospheric or magnetic shielding…
From this study it was concluded that flares can abruptly increase the radiation level on planetary surfaces and have the capability to disrupt potentially habitable conditions on planets. It was also found that the atmospheric depth (column density) and planetary magnetic field are major factors in protecting planets from flares and maintaining a substantial planetary atmosphere.
New York University, “Exoplanets can be made less habitable by stars’ flares” at ScienceDaily, 15 December 2019

By some mere cosmic accident, these sudden radiation problems don’t affect us, right?

See also: What becomes of science when the evidence does not matter?

Comments

Jerry: I've thought about this for a while. There are a lot of variables. When you increase the mass of the planet you can hold more atmosphere and thus the pressure at the surface is higher. But not all that much higher in the ranges that we've discussed. Evaporation is affected by pressure. Would it be enough to disrupt the hydrological cycle? I don't know. Possible that there would be less rain and our environment much more desert like.....but....I would have no idea how to even model it. It would be much the same problem as modeling the climate which we have not had much success with to date.Latemarch_{December 23, 2019
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So actually the range of masses could be quite large for a habitable planet
Would the mass affect evaporation or how close to earth the water vapor stayed? If so at what size would water not evaporate into the atmosphere? Evaporation is essential or else there would be no distribution of water around planet. Also would ammonia and methane remain close to the surface in a larger planet? If so what level of diffusion is necessary so these compounds would not affect life? I understand that ammonia is toxic and methane is just dangerous.jerry_{December 23, 2019
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Jerry, ET: Gah! Of course not all planets have an atmosphere. I thought we were talking about habitable planets in the goldilocks zone. It wasn't clear to me what you were after. But some assumptions will have to be made. Given a planet with atmosphere in the habitable zone of an appropriate star. Assume the atmosphere is oxygen/nitrogen mixture like ours. Other mixtures have different densities and other problems. Does the mass of the planet affect the state of water and would that affect the accumulation of methane and ammonia? Yes as to water. To small (like Mars) there is insufficient gravity to hold enough atmosphere for the partial pressure to allow for liquid water (it boils if it's warm enough to be liquid and sublimates away if frozen). Still the absence of liquid water would not affect the accumulation of either methane or ammonia due to the mixing associated with wind and weather. Larger planet (high gravity) could be relevant. Assume the temperatures are in a habitable range. Water is not compressible it will remain a liquid. The heavy atmosphere shouldn't matter until you get to about 45 Atm where methane gas could precipitate as a liquid that might accumulate. Ammonia is 112 Atm. That would be a really big planet! There is an upper limit to the size of a planet as they begin to behave more like a brown dwarf star when they get big enough. So actually the range of masses could be quite large for a habitable planet though I wouldn't want to live on a heavy one it doesn't mean that other forms of life couldn't. Is that what your after?Latemarch_{December 22, 2019
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Mercury doesn't have an atmosphere. So I don't know how it can have any wind or weather. Are there winds on the Moon?ET_{December 22, 2019
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All planets, irrespective of mass, appear to have weather and wind.
I never said or implied that they don't. Jupiter is famous for weather incidents. But that all or most planets may have weather is irrelevant to my point. I am asking if the Earth was a different mass, would water exist in a way that it currently different than it does on Earth and consequently not be amenable to supporting life. Is there a Goldilocks mass range that leads to water in liquid form and also a gaseous form to distribute water over the planet. That also dispels poisonous gases of almost identical molecular weight away from life forms. It's hard to imagine a better system of water distribution than what exists on Earth. And is this distribution system a result of its mass?jerry_{December 22, 2019
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Jerry is correct. If we are searching for ET's that are capable of technology then we need to follow the criteria set by "the Privileged Planet". Unfortunately the people searching probably never read the book.ET_{December 22, 2019
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Seversky @ 10 " If we resemble God in certain ways..." I never claimed any such thing. Any being of the kind of intellect we're discussing is something beyond what any man can even begin to fathom. We try to find some way to understand, but no far too little about the universe to even begin to make a guess. Something created the math we have and will continue discover. Something created the absolutes that do exist in the universe. Something made man truly unique in our desire for order. Einstein certainly believed in God, for lack of a better word. He made it quite clear that the more he studied the universe, the more he believed in God.BobRyan_{December 22, 2019
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Jerry@13 "If methane and ammonia remained on the surface, they would poison most life forms." I guess that would be true and would also be true of carbon dioxide. But there is sufficient mixing (wind and weather) and diffusion to keep these gases at trace levels. It don't believe that the mass of the earth has much to do with it. All planets, irrespective of mass, appear to have weather and wind.Latemarch_{December 21, 2019
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I could be wrong but I believe that methane doesn’t escape
I should have been clearer. I meant escaping the surface of the earth. If methane and ammonia remained on the surface, they would poison most life forms. So if the Earth had greater mass, these two compounds would remain near the surface. If the Earth had less mass, then water wouldn't remain mostly on the earth but escape into the atmosphere. Some of it obviously does but not too far and we have an amazing water transfer system. If this is true about the effect of mass on water, Mars could never have retained its water whatever its source unless it was frozen. If what I am saying is true, then only exoplanets with a mass near that of Earth could hope to sustaIn life. I am just exploring this proposition. It seems reasonable to me and have been using it for years as another interesting fact about Earth when someone suggests that there are lots of other planets that could sustain life.. When I saw the article about exoplanets, I decided to ask the question to see what others know about the mass of the Earth and water.jerry_{December 21, 2019
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Jerry: "How many of the exoplanets meet all these criteria?" Unknown. We don't have all that much information about these exoplanets. "Also I believe there are other factors besides those in Privileged Planet." True, Privileged Planet is not a comprehensive list. "I believe there is a Goldilocks theory on the fine tuning of the mass of Earth so that water (molecular weight 18) will not escape easily but methane (molecular weight 16) and ammonia (molecular weight 17) will. I am not trying to make absolute claims but am interested in the physics of this." I'm unfamiliar with this fine tuning of the mass of the earth. I could be wrong but I believe that methane doesn't escape but is converted in the upper atmosphere by UV initiated reaction with oxygen to CO2 and water. Ammonia in the upper atmosphere is complicated because it is so soluble in water but perhaps not so much in ice. See here "When people talk of water on Mars, could Mars ever have the mass to keep water on the surface? Except in possibly a frozen state and that begs the question of how did this frozen water get there," There are no good theories as to how the water got there and why it should still be there a few billion years later. The usual explanation is that it was delivered by comets. Suspect answer. Collision with some body is the default explanation by astronomers for most anything odd that needs explaining.Latemarch_{December 21, 2019
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Back to exoplanets and away from God and His emotions and needs. What about all the factors in "Privileged Planet?" How many of the exoplanets meet all these criteria? Also I believe there are other factors besides those in Privileged Planet. I believe there is a Goldilocks theory on the fine tuning of the mass of Earth so that water (molecular weight 18) will not escape easily but methane (molecular weight 16) and ammonia (molecular weight 17) will. I am not trying to make absolute claims but am interested in the physics of this. When people talk of water on Mars, could Mars ever have the mass to keep water on the surface? Except in possibly a frozen state and that begs the question of how did this frozen water get there,jerry_{December 21, 2019
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BobRyan @ 6
Seversky @ 5 “It implies that He is a narcissistic being who feeds His fragile ego…” Those would be uniquely human traits, which is not found in nature. Where is ego to be found? It is only human beings who have egos and no animal, bird, insect, fish, etc. has anything close to what we have as people. If we are nothing more than animals, then we cannot be narcissists and ego is simply an imagined idea that does not really exist.
Imago dei. It must work both ways. If we resemble God in certain ways then He must resemble us in at least those ways. Human beings are prone to the temptation of trying to impress others with wealth and/or power for egotistical reasons. When it is suggested that God is trying to awe His subjects with demonstrations of His power, you are implying similar motivation. As for ego, I suspect it is not a binary situation. It's not that you either have an ego or you don't. There are probably degrees. My cats exhibit behavior which to me suggests they have egos although not in the way human beings have and I think the same is true of some other animals. Might there be extraterrestrial intelligences far older and wiser than we are? I see no reason why not. In that sense, atheists have a great advantage over believers. For an atheist, the confirmation of advanced ET, even in the form of the Christian God, would be a tremendously exciting discovery. We simply want to know the truth. For a believer, however, the discovery of the converse - that there is no God - would be a terrible blow, which explains their hostility to atheism.Seversky_{December 21, 2019
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Thanks, LM. I hope Sev and others will benefit.Silver Asiatic_{December 21, 2019
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SA@7 Brilliantly stated.Latemarch_{December 21, 2019
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Seversky
Have you considered the possibility that such a claim is potentially blasphemous in that it belittles God? It implies that He is a narcissistic being who feeds His fragile ego on the awe inspired in the minds of lesser beings by a demonstration of His great powers.
To me, this is one of the more challenging arguments raised by atheists. Philosophy gets us closer to an answer because first we accept that God does have great powers. We ourselves, as lesser beings, also possess great powers - but we are changeable, and anything that changes has potentiality which must be activated by a being that possesses the power to activate - so there is one being with full actuality and no potentiality. That Being has the completeness and perfection of power and does not get power from somewhere else. That Being gives power to all created beings. So, that power is evident in the expansive display of the universe. We then notice two things 1. - the power required to create the universe is immense and 2. the design, perfection, energies, laws, beauty and depth of the mysteries of the universe tells us that the Power is also incredibly intelligent. So, we respond with wonder, interest, appreciation … and eventually give glory to the creator of all of this. But still, the objection remains … Was this display of creative power merely the expression of a fragile ego who wanted to get attention from lesser beings? I fully agree that this is a blasphemous thought which demeans the goodness of God. It imputes an evil motive to God (egotism and vanity are moral defects) and it's similar to complaints that God is a tyrant. But I don't think most atheists are worried about blasphemy, so the concern remains. Is the display of beauty, power and magnificence done for selfish motives? Here's where I think philosophy does not help as much. We can see that there can be no lack of goodness (virtue) in God, and that His motive to create had to be one of love for creation. So, like a parent who teaches children to respect mother and father, and teaches children to be grateful for gifts received, God teaches us to appreciate great things, and the universe is a work of genius. So, it's not an expression of vanity for God to demand thanks for gifts. But was the expression of the creation itself just a attention-getting device by a god who needed praise to stroke his ego? Even after philosophical proofs that show this is impossible (there can be no defects in the moral character of God, since those defects are potentiality, and that leaves the mixture of actuality in God unexplained.). God is pure act, there can be no unrealized potential - so no moral flaw to overcome. But even still … I'm convinced by the philosophy, but I also think God Himself wanted to give a fuller, more convincing answer to this question. So, beyond philosophy, it's the life of Jesus that radically teaches us about the personality, nature and motives of God. This assumes that, at least for the sake of argument, you accept that Jesus is God - both fully human and also fully divine (hypostatic union). The single, radical, unique characteristic that Jesus showed about God - through His own life, is the humility of God. Beyond a doubt, that answers the problem. In the Deist view, for example, the Great Architect could be seen as distant, and perhaps even egotistical. The great Power. But with Jesus, we see God willing to be humiliated, rejected, tortured, ridiculed, opposed, ignored. Jesus received no glory from the world. His followers were outcasts, and even most of them were not faithful during his passion and death. Even the birth of Jesus, which we celebrate next week - was God showing his littleness. We know the story - Mary and Joseph could not even find a place to give birth. Jesus is born in a stable, with animals as his companions (and then shepherds, some very humble people themselves). This is God telling us, that it's not about His vanity. In the life of Jesus, He shows his littleness. Pascal said "God is the most vulnerable of beings". That's it. God has a lot to lose. He is not only ridiculed and rejected by his own creatures, but some deny that He exists. He is not loved. God took a big risk in creating free, independent beings. The love that God has for every person, is often betrayed. Can God suffer a broken heart from all of this? Philosophically, in a technical sense, it wouldn't seem possible. But that's where I look to the life of Jesus as an expression of the humility of God. So yes, I think God does suffer from a broken heart from many of His creatures. The classic image in traditional Christian art is Jesus' heart being pierced by the lance. It's not an expression of fragile ego but it's God wanting his beloved creatures to join Him and to be close to Him.Silver Asiatic_{December 21, 2019
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Seversky @ 5 "It implies that He is a narcissistic being who feeds His fragile ego..." Those would be uniquely human traits, which is not found in nature. Where is ego to be found? It is only human beings who have egos and no animal, bird, insect, fish, etc. has anything close to what we have as people. If we are nothing more than animals, then we cannot be narcissists and ego is simply an imagined idea that does not really exist. There are absolutes that exist in the universe, which must come from somewhere. Every mathematical equation that will ever be known is already there and math must have come from somewhere. Both of which do lead towards something with an intellect far greater than man could ever begin to fathom and only man is capable of seeing the order of the universe. Nature is chaotic and man seeks to bring order to the chaos.BobRyan_{December 20, 2019
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Latemarch @ 4
Sev@3 Not meant to be inhabited. Meant to show His glory and power.
Have you considered the possibility that such a claim is potentially blasphemous in that it belittles God? It implies that He is a narcissistic being who feeds His fragile ego on the awe inspired in the minds of lesser beings by a demonstration of His great powers.Seversky_{December 20, 2019
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Sev@3 Not meant to be inhabited. Meant to show His glory and power. Psalm 19:1-4 (NIV) 1The heavens declare the glory of God; the skies proclaim the work of his hands. 2Day after day they pour forth speech; night after night they reveal knowledge. 3They have no speech, they use no words; no sound is heard from them. 4Yet their voice b goes out into all the earth, their words to the ends of the world.Latemarch_{December 20, 2019
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As has been noted before, what a wonderfully hospitable universe God provided for his favored creatures.Seversky_{December 20, 2019
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Most exoplanets that have been discovered orbit around red dwarf stars.
Approximately three-quarters of the stars in our galaxy are red dwarfs. Most of the galaxy's "habitable-zone" planets — planets orbiting their stars at a distance where temperatures are moderate enough for liquid water to exist on their surface — likely orbit red dwarfs. In fact, the nearest star to our Sun, a red dwarf named Proxima Centauri, has an Earth-size planet in its habitable zone.
Superflares from young red dwarf stars imperil planets These stars are unstable and flare often. And because they are red dwarfs (type M) stars the habitable zone is close. A fatal combination: large, frequent flares and small distance. Our sun however is a main sequence star (type G luminosity V) A much more stable star that puts the habitable zone much further out where flares that do happen occasionally even in type G stars have much less effect. Oh, and type G stars make up less than 10% of the stars in the galaxy. The OP said, with what I can imagine was a sly smile, "By some mere cosmic accident, these sudden radiation problems don’t affect us, right?" If you are one of those that think that it's all just a cosmic accident might want to watch Privileged Planet. Start at 20 min if you don't want to watch it all.Latemarch_{December 20, 2019
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It helps that our sun is an unusually quiet star. It's not too big, not too small, it's just right.aarceng_{December 20, 2019
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