Quote from: Torbjorn Larsson, OM on 01/13/2015 06:04 pmI would add to Anderson's writ that Vasavada rejects Noffke's claim that there are no potential confusions (false positives) at her state of checking off on her MISS tests list, on Earth. (She do want to make a complementary microanalysis and a search for potential false positives, to make sure.) Either Vasavada makes a blanket claim that Noffke is wrong, or he has observations that would teach MISS experts something new.In either case it would be useful, not least for strategies on rover science, if Vasavada wrote a counter-article that lays out his evidence for errors or Mars's unique MISS-like geological processes.Can Curiosity's team really leave this behind as "a causal dismissal", especially since the 2020 rover isn't finalized? Any thoughts?I don't think Vasavada has any personal competence to assess Noffke's paper. He is not a geologist, let alone a palaentologist, has not done any field work on any planet, he's a physicist and a modeller.Of course here I assume he is speaking for the team. Right or wrong the team, including people who were competent to make the call decided that these features were not worth a closer look. It's too far away in time and space to go back and check again.All they can do is perhaps be a bit more alert to the possibility, should they see similar features, and perhaps look more closely.
I would add to Anderson's writ that Vasavada rejects Noffke's claim that there are no potential confusions (false positives) at her state of checking off on her MISS tests list, on Earth. (She do want to make a complementary microanalysis and a search for potential false positives, to make sure.) Either Vasavada makes a blanket claim that Noffke is wrong, or he has observations that would teach MISS experts something new.In either case it would be useful, not least for strategies on rover science, if Vasavada wrote a counter-article that lays out his evidence for errors or Mars's unique MISS-like geological processes.Can Curiosity's team really leave this behind as "a causal dismissal", especially since the 2020 rover isn't finalized? Any thoughts?
I don't see any impact for the 2020 mission myself, beyond a pointer to the possibility of returning microbial textures.
Chris McKay (who is on the Curiosity team) and Penny Boston (who isn't), both leading astrobiologists commented favourably on the paper. http://www.astrobio.net/news-exclusive/potential-signs-ancient-life-mars-rover-photos/
Why doesn't NASA send an actual life detection mission?
Quote from: Vultur on 01/17/2015 03:08 amWhy doesn't NASA send an actual life detection mission?Because there's nothing there.Everyone knows there's nothing there. That's why the goal has shifted to "evidence of fossil life" and other nonsense.
Quote from: QuantumG on 01/17/2015 03:44 amQuote from: Vultur on 01/17/2015 03:08 amWhy doesn't NASA send an actual life detection mission?Because there's nothing there.Everyone knows there's nothing there. That's why the goal has shifted to "evidence of fossil life" and other nonsense.Um... based on what? Endoliths could probably survive on current Mars just fine, if there's even tiny traces of water subsurface. Their requirements are extremely small (and being subsurface, the UV won't bother them).I see absolutely no reason to think that current life on Mars is unlikely.EDIT: And anyway, NASA hasn't even sent a lander/rover that could look for evidence of fossil life!
the bigger problem is that we STILL don't have a definitive chemical signature that we can point to and say "look! here is life!" there is no magical "life detection" box that we could send to Mars yet. yes, the technology we've got today is much better than it was for Viking, but there is still no consensus for what needs to be looked for when we are searching for life. the proposed instruments that we'd use to search for life have lots of limitations.
and i'd argue that NASA has sent both landers and rovers that can look for evidence of fossil life, or even current life, anything that is within their capabilities to see, they could find. Curiosity's MAHLI is capable of taking images 13.9 microns per pixel, for example, and there are lots of life-forms here on Earth that are larger than that.
QuantumG may have stretched a bit the conclusions, but the number of (informed) scientists thinking there is life on Mars is marginal shrinking (when one exclude those with a conflict of interest. )
Quote from: whitelancer64 on 01/18/2015 07:34 pmthe bigger problem is that we STILL don't have a definitive chemical signature that we can point to and say "look! here is life!" there is no magical "life detection" box that we could send to Mars yet. yes, the technology we've got today is much better than it was for Viking, but there is still no consensus for what needs to be looked for when we are searching for life. the proposed instruments that we'd use to search for life have lots of limitations. Sure, it's not an easy problem, but that's no reason not to try. Viking tried with what was available back then; the field has advanced to the point that I think it's time to try again.If Mars life is nucleic acid based (which seems not unlikely) it should be (comparatively) easy to unambiguously identify. If not, the best route IMO would be to look for really complex organic molecules with structures that suggest "biomolecules" (with a non-heating-based method like a Raman spectrometer, not SAM - which I think ExoMars and Mars 2020 are supposed to have).Quoteand i'd argue that NASA has sent both landers and rovers that can look for evidence of fossil life, or even current life, anything that is within their capabilities to see, they could find. Curiosity's MAHLI is capable of taking images 13.9 microns per pixel, for example, and there are lots of life-forms here on Earth that are larger than that.Sure, but the life wouldn't be on the surface due to UV - it would be subsurface, maybe shallow, but not exposed. You have to scoop and drill.Microfossils or stromatolite-type things might be found, but identifying them unambiguously enough to convince the scientific community from a MAHLI image alone seems unlikely.
Quote from: Vultur on 01/18/2015 07:16 pmQuote from: QuantumG on 01/17/2015 03:44 amQuote from: Vultur on 01/17/2015 03:08 amWhy doesn't NASA send an actual life detection mission?Because there's nothing there.Everyone knows there's nothing there. That's why the goal has shifted to "evidence of fossil life" and other nonsense.Um... based on what? Endoliths could probably survive on current Mars just fine, if there's even tiny traces of water subsurface. Their requirements are extremely small (and being subsurface, the UV won't bother them).I see absolutely no reason to think that current life on Mars is unlikely.EDIT: And anyway, NASA hasn't even sent a lander/rover that could look for evidence of fossil life!QuantumG may have stretched a bit the conclusions, but the number of (informed) scientists thinking there is life on Mars is marginal shrinking (when one exclude those with a conflict of interest. )The point is that repeating ad nauseam that there MAY be life on Mars doesn't make life more likely.
Quote from: pagheca on 01/18/2015 07:38 pmQuote from: Vultur on 01/18/2015 07:16 pmQuote from: QuantumG on 01/17/2015 03:44 amQuote from: Vultur on 01/17/2015 03:08 amWhy doesn't NASA send an actual life detection mission?Because there's nothing there.Everyone knows there's nothing there. That's why the goal has shifted to "evidence of fossil life" and other nonsense.Um... based on what? Endoliths could probably survive on current Mars just fine, if there's even tiny traces of water subsurface. Their requirements are extremely small (and being subsurface, the UV won't bother them).I see absolutely no reason to think that current life on Mars is unlikely.EDIT: And anyway, NASA hasn't even sent a lander/rover that could look for evidence of fossil life!QuantumG may have stretched a bit the conclusions, but the number of (informed) scientists thinking there is life on Mars is marginal shrinking (when one exclude those with a conflict of interest. )The point is that repeating ad nauseam that there MAY be life on Mars doesn't make life more likely.I don't think the number scientists that think there might be life on Mars is shrinking. If anything its increasing.
Precisely that was my reading of the situation as well. Not sure where the OP got the idea from that it was shrinking number and would in fact ask them to present some kind of evidence to back up that statement so counter to the actual situation is it.
An informal poll of 250 scientists attending the Mars Express Science Conference at Noordwijk in the Netherlands last month revealed how high their hopes have climbed. About three-quarters think life could have existed on Mars in the past, and a quarter think life could be there today.
Quote from: Star One on 01/19/2015 08:12 amPrecisely that was my reading of the situation as well. Not sure where the OP got the idea from that it was shrinking number and would in fact ask them to present some kind of evidence to back up that statement so counter to the actual situation is it.Just an impression, I will candidly admit that. I spoken with several colleagues about that in some occasions and I got the impression that a lot of professional astronomers, if obliged to bet, would now say there is no life at present on Mars (maybe in the past) after some past bandwagon effect.This is not enough to say "there is no life at present on Mars", neither to conclude the number of scientists believing there is is shrinking, but I got the impression that the general public is much more positive about the idea (again: life on Mars TODAY) than informed scientists.Now, by looking to the internet to investigate more about this quite interesting issue (what planetary scientists think about the chance of life on Mars), I found a 2005 Nature paper saying that QuoteAn informal poll of 250 scientists attending the Mars Express Science Conference at Noordwijk in the Netherlands last month revealed how high their hopes have climbed. About three-quarters think life could have existed on Mars in the past, and a quarter think life could be there today.So, apparently at the time - almost 10 years ago, therefore before most of the rovers works came out - the number was rather increasing. It would be very interesting to check the number now at a similar intl. conference. However, this was people attending a "Mars Express" conference, so, highly tied to this hope. STANDARD DISCLAIMER: just to clarify, I'm not interested in defending one or the other position, and I'm ready - as always - to change opinion or even to renounce to an opinion. At the end of the day, what scientists believe is less relevant than what they know, but up to when the limited, available funding must be directed toward one or other competitive targets. My impression is, again, that this "life on Mars" thing has been quite pimped up in the past to obtain more funding (example: don't be a Venus planetologist today, as your chances to get funded are quite dimmed) and because was obviously nice meat for the general media. Every single result was immediately accompanied with the claim that this show that look! There MAY BE life on Mars (look for example at that methane fluctuation issue), stretching evidences and transforming an hypothesis almost in a certainty by talking about that over and over. Please read carefully what I said. I'm not embracing one or another position on this quest at this point, but I rather think it's very difficult to be unbiased after so much continuous talking about life on Mars. I always feel like whatever I think it's because I'm biased.
Which is not the impression of what your position was in your OP.