Dragon01

Members
  • Content Count

    5,108
  • Joined

  • Last visited

Community Reputation

1,255 Excellent

About Dragon01

  • Rank
    Flight Director

Recent Profile Visitors

The recent visitors block is disabled and is not being shown to other users.

  1. I'm not, but having life in Venusian atmosphere does seem to require the microbes to reproduce rather briskly. I'm assuming that the conditions there allow them, which is a weaker assumption. In particular, the environment this paper deals with is extremely static, and also very low in energy. Atmosphere of Venus is completely different, so your example is not relevant. Energy (from either light or chemical reactions) is available on Venus, and so is carbon. These typically have a greater influence on reproduction rate than other environmental conditions. On top of that, the nature of the environment favors r-selected organisms. Organisms living on Venus would likely be significantly slower to reproduce than Earth ones, but they couldn't be slow in absolute sense, because such a species would be too vulnerable to being wiped out by capricious atmospheric currents.
  2. Mr. B.S. Johnson and his mail sorting machine would like a word with you.
  3. FYI, Cougar is not an RD-180 equivalent. It's the RD-701, projected engine for MAKS spaceplane: It should have the option of switching between LH2 and kerosene fuel (the real one did), but this isn't implemented.
  4. If they live in a_w of 0.15, then they would likely reproduce slowly, but seeing as this are "normal" conditions on Venus, they could then do so continuously. If they just have to survive those conditions and only reproduce when they run into an area where it's locally higher, they could do it more quickly. Both are potentially viable approaches to the problem. In fact, organisms using both of those strategies could very well coexist. It's extremely unlikely that if we find extraterrestrial life, it'll be just one species, reliant on one strategy. Yes, specialized organisms can reproduce relatively slowly, but most of them still do this reasonably fast. "Much slower-breeding than bacteria" isn't saying much, seeing as bacteria reproduce ridiculously quickly if they have everything they need. Also, atmospheric circulation is complex, but not random, and there could be areas where air masses circulate at a narrow range of altitudes, much like jetstreams on Earth. Something carried by the wind in such areas would stay aloft for a really long time. Again, we need to know more about weather on Venus, not just its climate, to estimate such things accurately. Life on Earth, up to and including humans, greatly alters its behavior to account for the weather, and life cycles of many species are dependent on its peculiarities. There's no reason for life anywhere else to be any different in that regard.
  5. @Zorg, @CobaltWolf, would that be possible to make a variant of LR-79 with an integrated steering nozzle? I always disliked the way the Jupiter one is set up, but I assumed it was because switching a gimbaled nozzle on and off was not possible. However, the RS-68 does include that functionality, so it's not that. I'm asking because having the nozzle as a separate part, besides making no sense (the exhaust nozzle is part of the engine IRL), can lead to silly results with a part failure mod, which can cause either of them to fail separately.
  6. It very much is an option, it just has to reproduce, during the activity period, at sufficient rate to exceed the number that fell down since the last event. Microbes can float with the wind for a long time (and the winds on Venus are very strong), and they very much do go on a reproduction frenzy if they encounter the right conditions. Also, remember that Earth life of this kind is mostly confined to one spot, while on Venus, it would have the whole planet to work with. This requires more research, but I don't think we're talking an event that's ultra-rare on a planetary scale. At most, you can invert the usual arrangement, with most of the organism nonpolar, and water inside the membranes and micelles. Besides, the amount of observable water is not the problem, it's more than enough. The problem is in its availability, H2SO4 is incredibly higroscopic, and presently, it seems to be hogging all of it. So, anything living out there would have to either find higher local concentrations of water, or find a way to wrestle it from the sulfuric acid, which would be quite an achievement. It's just like the thing with carbon, water is pretty much unique, with only one, somewhat poor analogue. These properties both contribute to allowing both of them to create structures several orders of magnitude more complex than any others. That is hopefully something we're going to do. In absence of an in-situ probe, we'll have to make best of the measurements we can run with the existing equipment. I imagine Akatsuki will be getting a lot of attention in the coming days.
  7. IIRC, this method has a poor spatial resolution, even from orbit. In fact, this is similar to a way we found phosphine. We can analyze the whole planet or large areas of it, but what I've seen of it can only tells us about climate and not the weather. We already know there's water vapor in Venusian atmosphere, and enough of it to make clouds that consist of sulfuric acid (which requires some water to even exist). Finding out how exactly it's distributed is harder. And yes, it might require a dedicated instrument designed specifically to detect water. Such devices have been sent to Mars, for example MARSIS on Mars Express. Water is a factor, as I explained in a lengthy post earlier in the thread. There are very good physical reasons for it being important in anything resembling life, most notably everything about hydrogen bonds. Not only that, it has to be present in liquid phase, though that's not all that hard, because its liquid phase exists over a huge (relative to other materials) pressure and temperature range. The only thing that comes close would be ammonia, but that would require very low temperatures.
  8. Raddus was big, but so was Supremacy. That said, we never saw a proton bomb of comparable size. Kilogram for kilogram (or credit for credit), proton or thermal warheads are probably more efficient than hyperdrives, seeing how just one bomber full of those demolished a 8km long dreadnought. Plus, interdictor cruisers are canon. They presumably no longer work by emulating a planet, but either way, put one of those in the middle of the fleet and watch all hyperspace trickery end at the fields' edge (right in your turbolaser range, for added points). Well, that, and SW universe seems to be averse to missiles in general, presumably due to cost and logistics.
  9. That's why we need to send a probe, and watch the atmosphere for a long time from up close, not intermittently and/or from orbit. We have a good picture of how it looks like from orbit, but remember that there are three tiers of clouds on Venus, of which only the topmost one is really visible from orbit (some instruments can penetrate it to a degree, but this has limits). Venusian atmosphere, like Earth's, is a very dynamic system, and Pioneer multiprobe, while a very useful mission, wasn't really geared for looking for water, not to mention the observation time was very short. Only the two Vega missions carried balloon probes that got a good look at the middle layer, and those were quite small, uncontrolled and had few instruments. Quite frankly, anything living there would likely have to be immune to the acid either way (in fact, it's easier to be acid-immune when dried out), so spreading might actually be a good thing for them. It would be hard to live in those conditions, but as long as water is there, it would be possible. Pulling it out of sulfuric acid is a tall order, but it's not necessarily all bound up like this.
  10. The less said about lightspeed ramming, the better. Though it actually doesn't contradict that specific part at all. Velocities and positions of planets are known, and all ships presumably have this information in the navigation database. Exploration of uncharted systems and lanes is often said to be dangerous, without such data it certainly would be. Hyperspace navigation is often stated to be a nontrival problem in SW universe, needing a lot of dedicated hardware, so I think this is a reasonable assumption. You could probably get it to exit at any speed, if you overrode those parameters (hyperdrives are likely too expensive to use on dedicated missiles, though I'm fully expecting a future movie to feature such weapons, anyway).
  11. All right, there are some abiotic processes that could make it, but this is besides the underlying point. Phosphorus in phosphine is very reduced, and this is not a chemically optimal state for it to be in, in conditions similar to those on Venus. It is possible we are misestimating one of the abiotic processes, but highly unlikely. Discovery of either life or a previously unknown abiotic route are more likely than either of known ones doing a whole lot here. Besides Venus Express, how many of them actually measured the water content in the clouds? Venera probes had pretty basic equipment, and most of them were landers, anyway, with instrumentation mostly focused on studying the surface and the lower atmosphere. Venus Express, at least, was specifically designed to study atmosphere. At any rate, the papers I've seen primarily cite Venus Express data. Stability is not really a requirement. Some Earth plants (not even microbes, plants!) live for a few days of rain per year, or even several years, and spend most of their lifetime almost completely dried out. Life only has trouble in places where there's never any water, period.
  12. FYI, SW fans had these things worked out a long time ago. This was a community effort, so to speak.
  13. Wrong. First of all, phosphine is a biomarker not based just on empirical evidence, but also thermodynamics. We can use phosphine as biosignature, because all known abiotic routes require greater temperatures than found on Venus. Outside gas giants, it is not something that can easily arise on its own, and besides life, we don't really know of any ways to drop energetic requirements for forming such molecules by that much. Second of all, it's not even based on known anaerobic life, just suspected. Basically, they noticed it's produced by sludge, and that sterilizing the sludge removed this production, while adding glucose increased it. The exact organism had not been identified, and it would itself be a highly unusual one, due to aforementioned thermodynamics. I suppose they'll get back to looking to it now (read: some hapless grad student will have to sift through jars of sludge and culture the critters found in it ). Also, I've already mentioned the possibility of our models being wrong, particularly with regards to water content. The best data (the one used in the paper you cited) we have on this is from Venus Express, an orbiter. It indeed saw clouds that were mostly acid, but we don't really know whether these conditions are all that that exists on Venus, or if there are times or places when much higher water availability can be found. Wrong. First of all, phosphine is a biomarker not based just on empirical evidence, but also thermodynamics. We can use phosphine as biosignature, because all known abiotic routes require greater temperatures than found on Venus. Outside gas giants, it is not something that can easily arise on its own, and besides life, we don't really know of any ways to drop energetic requirements for forming such molecules by that much. Second of all, it's not even based on known anaerobic life, just suspected. Basically, they noticed it's produced by sludge, and that sterilizing the sludge removed this production, while adding glucose increased it. The exact organism had not been identified, and it would itself be a highly unusual one, due to aforementioned thermodynamics. I suppose they'll get back to looking to it now (read: some hapless grad student will have to sift through jars of sludge and culture the critters found in it ). Also, I've already mentioned the possibility of our models being wrong, particularly with regards to water content. The best data (the one used in the paper you cited) we have on this is from Venus Express, an orbiter. It indeed saw clouds that were mostly acid, but we don't really know whether these conditions are all that that exists on Venus, or if there are times or places when much higher water availability can be found.
  14. No, but it is needed for finding possible non-biological explanations for the origins of phosgene. This also needs to be considered, we don't really know where exactly to look in the clouds, and even if there really is something alive up there. We need to know more about the surface, too.