julius2 Posted December 31, 2023 Share Posted December 31, 2023 Since this is the Speculations forum, I thought I might broach something speculative and quite unsubstantiated. One thing I noticed, and probably everyone else, that Earth appears to be the only place in the currently known universe to harbour life. If we were to put this in to an index, Earth = 8 billion + plant life + animal life. Quite a high number. But for stars index = 0.0. Plus all other discovered planets index = 0.0 We are like a massive black hole with everything else relatively insignificant in terms of a life index. Of course we wouldn't survive without the sun.... On another note, our quest is to discover life somewhere else in the universe. But space travel , the medium of transport is so "messy" for humans. We try to put ourselves in to spacecraft equipped with oxygen tanks to travel amazing distances. I wish there was something more "elegant". Perhaps wormholes close to Earth that transport us or link us to Other Worlds. Link to comment Share on other sites More sharing options...
npts2020 Posted December 31, 2023 Share Posted December 31, 2023 You need to better define what"life" is. If we are talking about organisms like viruses, there are indications there could be life on other planets or their moons in our solar system. If we are referring to LGM (little green men) or the like, the jury is probably still out. Humans have only been able to even detect a planet outside of our solar system for a bit over 30 years and we still have yet to develop the capability to determine exactly what is on any of those planets. OTOH, if you believe evolution to be a valid theory, mathematics say there should be life in many places, especially since some of those places have had a few billion more years to evolve than our small corner of the universe. Link to comment Share on other sites More sharing options...
julius2 Posted December 31, 2023 Author Share Posted December 31, 2023 33 minutes ago, npts2020 said: You need to better define what"life" is. If we are talking about organisms like viruses, there are indications there could be life on other planets or their moons in our solar system. If we are referring to LGM (little green men) or the like, the jury is probably still out. Humans have only been able to even detect a planet outside of our solar system for a bit over 30 years and we still have yet to develop the capability to determine exactly what is on any of those planets. OTOH, if you believe evolution to be a valid theory, mathematics say there should be life in many places, especially since some of those places have had a few billion more years to evolve than our small corner of the universe. Finding a virus like lifeform on a planet distant in the universe doesn't sound that exciting to me. Civilizations only! It's true that our universe exploration is relatively new. Who knows what we may discover given more time..... Link to comment Share on other sites More sharing options...
exchemist Posted December 31, 2023 Share Posted December 31, 2023 1 hour ago, julius2 said: Since this is the Speculations forum, I thought I might broach something speculative and quite unsubstantiated. One thing I noticed, and probably everyone else, that Earth appears to be the only place in the currently known universe to harbour life. If we were to put this in to an index, Earth = 8 billion + plant life + animal life. Quite a high number. But for stars index = 0.0. Plus all other discovered planets index = 0.0 We are like a massive black hole with everything else relatively insignificant in terms of a life index. Of course we wouldn't survive without the sun.... On another note, our quest is to discover life somewhere else in the universe. But space travel , the medium of transport is so "messy" for humans. We try to put ourselves in to spacecraft equipped with oxygen tanks to travel amazing distances. I wish there was something more "elegant". Perhaps wormholes close to Earth that transport us or link us to Other Worlds. What you say you have noticed is wrong. We simply do not know whether life occurs elsewhere, due to the difficulty of making the necessary observations. 1 Link to comment Share on other sites More sharing options...
julius2 Posted December 31, 2023 Author Share Posted December 31, 2023 30 minutes ago, exchemist said: What you say you have noticed is wrong. We simply do not know whether life occurs elsewhere, due to the difficulty of making the necessary observations. It is true it is difficult to make the necessary observations on exoplanets. I guess in nearby star systems for example Alpha Centauri and Sirius we have not found any life as yet. Stars would still have a life index of 0.0. I don't know what it would look like if there were civilisations on other exoplanets. Eg. Could we detect this? I guess my point is, we seem to have an abnormally high density of life here.... Why not be more evenly distributed? Link to comment Share on other sites More sharing options...
Arthur Smith Posted December 31, 2023 Share Posted December 31, 2023 (edited) 3 hours ago, exchemist said: What you say you have noticed is wrong. We simply do not know whether life occurs elsewhere, due to the difficulty of making the necessary observations. Not sure if this blog post from 2021 is still valid or if budget cuts will cause the venture to be cancelled. Edited December 31, 2023 by Arthur Smith Correct link Link to comment Share on other sites More sharing options...
exchemist Posted December 31, 2023 Share Posted December 31, 2023 4 minutes ago, Arthur Smith said: Not sure if this blog post from 2021 is still valid or if budget cuts will cause the venture to be cancelled. You will need to explain the relevance of that link. 2 hours ago, julius2 said: It is true it is difficult to make the necessary observations on exoplanets. I guess in nearby star systems for example Alpha Centauri and Sirius we have not found any life as yet. Stars would still have a life index of 0.0. I don't know what it would look like if there were civilisations on other exoplanets. Eg. Could we detect this? I guess my point is, we seem to have an abnormally high density of life here.... Why not be more evenly distributed? No, that is wrong. We do not know what the "normal" density of life is. We have no way to assess what is "normal" for the universe, due to the difficulty of detecting life elsewhere. According to my understanding (I am not a specialist in exobiology) the best we can currently do is look for the signatures of molecules that are relevant to the biochemistry we know from Earth, in the absorption spectra of planetary atmospheres. That is very hard to do, as planets are themselves too small to detect around anything other than very close stars, let alone measuring the absorption spectra of their atmospheres. The general default principle of cosmology, that there is no reason to think why our own solar system or galaxy should be special, suggests that since life has arisen here it will have arisen elsewhere, on planets with similar conditions. The question then becomes one of how common such planets are. That is a question people sometimes try to estimate but, given the size of the cosmos, it seems unlikely that these conditions occur nowhere. Link to comment Share on other sites More sharing options...
Arthur Smith Posted December 31, 2023 Share Posted December 31, 2023 3 hours ago, exchemist said: It refers to the ongoing Mars Perseverance mission, of which one objective is to return physical samples to Earth. The article discusses possible results from examining those samples and the implications. 12 minutes ago, exchemist said: You will need to explain the relevance of that link. Just now, Arthur Smith said: It refers to the ongoing Mars Perseverance mission, of which one objective is to return physical samples to Earth. The article discusses possible results from examining those samples and the implications. Link to comment Share on other sites More sharing options...
exchemist Posted December 31, 2023 Share Posted December 31, 2023 8 minutes ago, Arthur Smith said: It refers to the ongoing Mars Perseverance mission, of which one objective is to return physical samples to Earth. The article discusses possible results from examining those samples and the implications. OK thanks. (The link you supplied takes one to the middle of some piffling argument with a creationist, but scrolling to the top makes it clearer.) But that's just about Mars. If there continues to be no sign of life there, I don't think it provides a basis for extrapolation to other bodies we have not yet detected. Of course it does detect evidence of past life, that's highly significant, hence the interest. Link to comment Share on other sites More sharing options...
Arthur Smith Posted December 31, 2023 Share Posted December 31, 2023 12 minutes ago, exchemist said: OK thanks. (The link you supplied takes one to the middle of some piffling argument with a creationist, but scrolling to the top makes it clearer.) Sorry, I corrected the link. 13 minutes ago, exchemist said: But that's just about Mars. If there continues to be no sign of life there, I don't think it provides a basis for extrapolation to other bodies we have not yet detected. Of course it does detect evidence of past life, that's highly significant, hence the interest. Extrapolation may be justified, I suggest. What if the mission brings back evidence of micro-organisms fundamentally unlike that found on Earth? On that basis, separate abiogenesis events on two adjacent planets in one solar system, abiogenesis seems inevitable given the right range of conditions. Link to comment Share on other sites More sharing options...
exchemist Posted December 31, 2023 Share Posted December 31, 2023 16 minutes ago, Arthur Smith said: Sorry, I corrected the link. Extrapolation may be justified, I suggest. What if the mission brings back evidence of micro-organisms fundamentally unlike that found on Earth? On that basis, separate abiogenesis events on two adjacent planets in one solar system, abiogenesis seems inevitable given the right range of conditions. What I said was if there is no sign of life I don't think an extrapolation can be made. Link to comment Share on other sites More sharing options...
Arthur Smith Posted December 31, 2023 Share Posted December 31, 2023 (edited) Sure. But I would find it difficult to remain optimistic, even though it is the outcome I expect. Where are they? Anyway, the hiatus between yule and New Year will soon be over so much less time for me to comment. Happy New Year everyone. Edited December 31, 2023 by Arthur Smith Link to comment Share on other sites More sharing options...
dimreepr Posted December 31, 2023 Share Posted December 31, 2023 This question, for me, is akin to, will forest Green Rovers win the UEFA Champions League? The probability is low, but if they do it'll be a great day and then, meh... Link to comment Share on other sites More sharing options...
julius2 Posted January 1 Author Share Posted January 1 19 hours ago, exchemist said: You will need to explain the relevance of that link. No, that is wrong. We do not know what the "normal" density of life is. We have no way to assess what is "normal" for the universe, due to the difficulty of detecting life elsewhere. According to my understanding (I am not a specialist in exobiology) the best we can currently do is look for the signatures of molecules that are relevant to the biochemistry we know from Earth, in the absorption spectra of planetary atmospheres. That is very hard to do, as planets are themselves too small to detect around anything other than very close stars, let alone measuring the absorption spectra of their atmospheres. The general default principle of cosmology, that there is no reason to think why our own solar system or galaxy should be special, suggests that since life has arisen here it will have arisen elsewhere, on planets with similar conditions. The question then becomes one of how common such planets are. That is a question people sometimes try to estimate but, given the size of the cosmos, it seems unlikely that these conditions occur nowhere. I take your point. Since we have not properly explored the universe or are yet to do it better, we do not know if there is more life out there. If we say discover a "twin earth", we could then assign a life index to it. For a "twin earth" it might be = 2 billion + plant life + animal life. Then we would have a better balance of life in the universe...... It would be interesting to know where in such a world's development it is. For sake of argument let us assume it is an older world than ours. It would be very difficult to find another world in at a similar development to ours due to the short timeframe of our development , say 1000 - 2000 years over a very long time frame. Link to comment Share on other sites More sharing options...
dimreepr Posted January 2 Share Posted January 2 On 1/1/2024 at 6:15 AM, julius2 said: I take your point. Since we have not properly explored the universe or are yet to do it better, we do not know if there is more life out there. If we say discover a "twin earth", we could then assign a life index to it. For a "twin earth" it might be = 2 billion + plant life + animal life. Then we would have a better balance of life in the universe...... It would be interesting to know where in such a world's development it is. For sake of argument let us assume it is an older world than ours. It would be very difficult to find another world in at a similar development to ours due to the short timeframe of our development , say 1000 - 2000 years over a very long time frame. If we find life elsewhere in the universe, what difference could it make??? We can't comunicate and we can't make a meaningful extrapolation, vis-a-vis the universe; IOW a meaningless project... But, it's a bloody good excuse for funding... Link to comment Share on other sites More sharing options...
julius2 Posted January 2 Author Share Posted January 2 8 hours ago, dimreepr said: If we find life elsewhere in the universe, what difference could it make??? We can't comunicate and we can't make a meaningful extrapolation, vis-a-vis the universe; IOW a meaningless project... But, it's a bloody good excuse for funding... Yes, I don't know. Are we able to communicate that far out? But I think we should make some efforts. People are leading the way. Only time will tell where we head with this. Link to comment Share on other sites More sharing options...
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