tag:blogger.com,1999:blog-4637778157419388168.post2579681368289689863..comments2024-03-21T09:01:08.175-07:00Comments on Physics with an edge: A Case for Human SpaceflightMike McCullochhttp://www.blogger.com/profile/00985573443686082382noreply@blogger.comBlogger13125tag:blogger.com,1999:blog-4637778157419388168.post-80661963875437068992015-11-20T08:49:56.397-08:002015-11-20T08:49:56.397-08:00This comment has been removed by the author.tonyonhttps://www.blogger.com/profile/08253501266473243514noreply@blogger.comtag:blogger.com,1999:blog-4637778157419388168.post-61934046281356485692015-11-19T04:15:16.727-08:002015-11-19T04:15:16.727-08:00This comment has been removed by the author.tonyonhttps://www.blogger.com/profile/08253501266473243514noreply@blogger.comtag:blogger.com,1999:blog-4637778157419388168.post-30988308093042164412015-11-18T02:03:42.435-08:002015-11-18T02:03:42.435-08:00This comment has been removed by the author.tonyonhttps://www.blogger.com/profile/08253501266473243514noreply@blogger.comtag:blogger.com,1999:blog-4637778157419388168.post-15443351564093478892015-11-17T13:17:33.711-08:002015-11-17T13:17:33.711-08:00This comment has been removed by the author.tonyonhttps://www.blogger.com/profile/08253501266473243514noreply@blogger.comtag:blogger.com,1999:blog-4637778157419388168.post-9115194744693423772015-11-17T02:28:45.253-08:002015-11-17T02:28:45.253-08:00Venus is indeed a better destination than any othe...Venus is indeed a better destination than any other planet in the system if you don't plan to settle the ground at least. <br /><br />http://www.datasync.com/~rsf1/vel/1918vpt.htm<br /><br />The temperature / pressure profile of the atmosphere of Venus is interesting. 1bar pressure have a sustainable temperature for humain being.<br /><br />Zeppelin FTW.<br /><br />It would be possible to build cities in the sky here! :)<br /><br />Czekohttps://www.blogger.com/profile/04231020181834141834noreply@blogger.comtag:blogger.com,1999:blog-4637778157419388168.post-26670753780717360552015-11-16T07:19:49.278-08:002015-11-16T07:19:49.278-08:00This comment has been removed by the author.tonyonhttps://www.blogger.com/profile/08253501266473243514noreply@blogger.comtag:blogger.com,1999:blog-4637778157419388168.post-67806596301779737242015-11-15T13:54:02.887-08:002015-11-15T13:54:02.887-08:00This comment has been removed by the author.tonyonhttps://www.blogger.com/profile/08253501266473243514noreply@blogger.comtag:blogger.com,1999:blog-4637778157419388168.post-27952676523536561492015-11-15T13:15:45.128-08:002015-11-15T13:15:45.128-08:00Tonyon: Good scenario. We need to start thinking a...Tonyon: Good scenario. We need to start thinking about how to get the 1g acceleration you mentioned. MiHsC does have something to say about the speed of light limit. It disallows a constant velocity (zero acceleration) so the usual speed of light limit of relativity is ever so slightly weakened, but I don't know what that means for causality yet. In my speech I focused on what we can do with special relativity, which as you know makes interstellar travel far more possible than most people believe. We just need that powerful engine.Mike McCullochhttps://www.blogger.com/profile/00985573443686082382noreply@blogger.comtag:blogger.com,1999:blog-4637778157419388168.post-53571940524906596852015-11-15T13:08:33.187-08:002015-11-15T13:08:33.187-08:00qraal: I had a discussion on self-directed evoluti...qraal: I had a discussion on self-directed evolution with someone after the debate. They wanted to settle Venus! Thanks for the link, I've read Schulz-Makuch's book 'We are not alone' and he has a lot of interesting things to say. Life just requires some chemistry that repeats, and there may be many ways to do that: I remember one far-sighted episode of Star Trek with a silicon-based lifeform.Mike McCullochhttps://www.blogger.com/profile/00985573443686082382noreply@blogger.comtag:blogger.com,1999:blog-4637778157419388168.post-47898124603119060692015-11-14T13:28:42.405-08:002015-11-14T13:28:42.405-08:00Tonyon, I am not sure that Mike's theory allow...Tonyon, I am not sure that Mike's theory allows superluminal travel, but nice work anyway.qraalhttps://www.blogger.com/profile/13436948899560519608noreply@blogger.comtag:blogger.com,1999:blog-4637778157419388168.post-77430825124847897412015-11-14T12:27:59.570-08:002015-11-14T12:27:59.570-08:00This comment has been removed by the author.tonyonhttps://www.blogger.com/profile/08253501266473243514noreply@blogger.comtag:blogger.com,1999:blog-4637778157419388168.post-61471004119003061502015-11-14T03:53:31.933-08:002015-11-14T03:53:31.933-08:00For a plausible hydrogen-based biosphere, there...For a plausible hydrogen-based biosphere, there's this paper by Bains, Seager & Zsom:<br /><br />http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4284464/<br /><br />Photosynthesis in Hydrogen-Dominated Atmospheres<br /><br />...considering the evidence that most stars have super-Earths and they're likely to have H2 dominated atmospheres, then the odds are in favour of such environments being the dominant type for Life to evolve in. Assuming it can, that is.<br /><br />If so, then an oxygenated biosphere would seem like science fiction to *most* intelligent life in our Galaxy...qraalhttps://www.blogger.com/profile/13436948899560519608noreply@blogger.comtag:blogger.com,1999:blog-4637778157419388168.post-30642655845351315252015-11-14T03:31:48.746-08:002015-11-14T03:31:48.746-08:00One thing we should embrace about settling other w...One thing we should embrace about settling other worlds is that the experience may change us in ways we can't yet imagine. My favourite fictional attempt in that direction is James Blish's old stories about pantropy (defined as the deliberate engineering of humans adapted to new environments) collected in his "Seedling Stars" anthology is just one example of such imagining what that might mean. As our understanding of how our kind of biology works grows exponentially, then we get closer to being ready to engineer ourselves. <br /><br />Whether we'll take that step, I think only off-world colonies will provide sufficient impetus. Worlds exactly like our own are incredibly unlikely and any attempted terraforming will be a protracted affair. The current definition of the "habitable zone" relies on high levels of CO2 to be as wide as it currently is. We might do better to meet other worlds part way, expanding the abilities of "natural humans" to live in environments with more CO2, CO, H2S, NO2, NH3 and similar 'poison' gases that different animals on Earth have adapted to. <br /><br />More speculatively, there's considerable literature on "habitable planets" with hydrogen-rich atmospheres. Such worlds can maintain liquid water oceans out to the orbit of Saturn and still get enough sunlight to maintain photosynthesis. Could animals adapt to hydrogen in place of oxygen? Intriguingly there are animals that live at the bottom of the Mediterranean which live without oxygen and use hydrogenosomes in place of oxygen-using mitochondria to make ATP for powering their life processes. <br /><br />More speculative biochemistries have been discussed in the literature, but we don't presently have any living examples to study - adding another argument to the case for interstellar travel. qraalhttps://www.blogger.com/profile/13436948899560519608noreply@blogger.com