5 ms·

I don't understand all the hubbub around looking for life on Mars. Is there any credible reason whatsoever to assign a non-negligible probability to there havin

by jey 19y ago

I don't understand all the hubbub around looking for life on Mars. Is there any credible reason whatsoever to assign a non-negligible probability to there having been life on mars? It seems to me like it's a PR trick cooked up by NASA to keep the public interested. Nobody cares about soil composition, but everyone is excited by a mission to find Martian bacteria.

mberning 19y ago
I think there has been due diligence in asking the question "Did Mars have a significant period in it's history that it could have been habitable?". The answer to that question is "yes"; data suggest that Mars had a significant wet period. There are no bounds on what we might find if we can scrape a way the first few feet of sediment.
ingenium 19y ago
Mars almost certainly doesn't have life anymore, except maybe underground or in caves or something. The thing is that Mars used to be very similar to Earth, and it's even been suggested that life was seeded on Earth from Mars. What they are looking for is signs that Mars had life at some point in the past, because it would prove that life is not something that is unique and special to Earth. Also, I would be very curious how Martian life differed from life on Earth on a molecular level. I'd be willing to bet they were based on the same principles, but diverged pretty quickly. For example, they may not use the structure of the amino acid to produce protein, which is: H NH3-C-COOH | functional group If they did, they probably don't use the same codon code to present them in RNA or have the same functional groups that all Earth based life does. I'm certain there is life places other than Earth, but the question is what does that life look like? It may not even remotely resemble Earth based life. Finding life on Mars might give us a clue about what types of things to look for to identify life elsewhere.
- asdflkj 19y ago
  >I'm certain there is life places other than Earth, Any evidence for that? Edit: this is my pet peeve, and I'm still peeved, so I'll write some more. Nobody has any idea how probable the appearance of life is. Nobody even has an idea how it happened. The only thing we do know about that probability is that it's very low, since we haven't been able to observe life anywhere. Just how low is anyone's guess. It could be 1/(number of particles in the universe * googolplex). Or it could be much lower still. My other pet peeve is singularity. If you show an 19th century man our world and give him the definition of singularity, he'll tell you it already happened. That's because it's totally meaningless, and essentially amounts to this: "singularity is when technological progress goes so fast, that, like, dude, totally". There, now I feel better.
  - DanielBMarkham 19y ago
    Just playing devil's advocate here, we're alive, aren't we? So the odds can't be much less than 1/(number of planets in the universe) As for the singularity, I believe the point is the nature of being a human will change. The 19th century man will fit into our world just fine. A "regular" man might not fit into a world where we're all part cyborgs. You are correct in that it's the same unknowable impenetrable future state for us and the 19th century guy, but the idea is that the nature of change will be different in the next 100 years than it ever has been -- because it deals with what it means to be human. The Fermi Paradox, Drake Equation, and the quest for life is one of my pet subjects. I like it because it is pseudo-science -- and I mean that in a good way. We simply have no means of actually performing experiments, since our knowledge of life consists of just one example for a brief period of time. I am tempted to think that life is just about everywhere in the universe, but heck if I know. If there is life everywhere, then where is everybody?
    - deleted 19y ago
      [deleted]
    - asdflkj 19y ago
      >we're alive, aren't we? So the odds can't be much less than 1/(number of planets in the universe) That argument takes for granted that the probability space comprises only the things in our observable universe. In other words, it claims that there doesn't exist anything that we don't already know about. That's a false premise. re: singularity. I think we are already part-cyborgs. For all practical purposes, Internet is a part of me--it's a sense organ. Ask yourself, what would you rather lose: your sense of hearing, or the technologies of the last 100 years? For me, it's the former, any day of the week. What it means to be human changes continuously, and has been changing since before we were officially human. Now it's changing faster than ever before, but it changed faster than ever before at almost every point in human history.
      - DanielBMarkham 19y ago
        "In other words, it claims that there doesn't exist anything that we don't already know about." -- that's not a false premise, that's the basis for science. I can only deal with things I can observe. If you put 4 black balls and one white ball into a bag and ask me the chances of drawing a white ball, it's 1/5. If you then say, "hey -- but I really put 9 black balls in there. Your math is wrong" that's not much in the way of an argument. We measure and calculate those things we can observe. Yes, one could speculate on non-observable things. But that's a game that has no end. We are conceptually part cyborgs. I think there will be a line that is crossed, perhaps in our lifetime, where the average person will be physically part cyborg. No matter how you measure it, that's a change of a different nature than simple discovery and invention. I think you are muddling the point a bit. One of the reasons the Fermi Paradox and Drake Equation are so interesting to me is that they rely on speculation. While I think the minimum is 1/(number of planets), who knows what that number is? And for all the other terms in the Drake Equation, you're just pulling numbers out of the air. It's as much a religion as science. Fascinating stuff, both from a science angle and as an observation of human nature.
ivankirigin 19y ago
We have one sample of life in the universe. Life on Mars would mean two. The difference from a scientific perspective is HUGE.
- jey 19y ago
  Yes, I fully agree. My question is why we should expect the probability of there being life on Mars to be appreciably above zero. It sounds like wishful thinking. As far as we know, life is not something that happens often nor easily, and there isn't any significant indication that there's life on Mars. So far it seems like we've picked our favorite hypothesis (that there's life on Mars) and are now scurrying around looking for any bits of evidence to support it. "Oooh look, there's some water! And some silica!" I'll avoid drawing the obvious comparison to creationism. Oops, too late. ;)
  - ingenium 19y ago
    Life actually is pretty common I think. The simplest definition of life would be molecules that replicate. An example of an arguably form of life in space can be found at http://www.sciencedaily.com/releases/2007/08/070814150630.htm http://www.sciencedaily.com/releases/2007/08/070814150630.ht... When you look at the way evolution works, it becomes clear that there is life elsewhere. Let's take a set of atoms. When they're bombarded with energy they react with each other and form compounds. While predictable, there is a slight amount of randomness in this. Eventually, one of these will be able to replicate itself. A simple example is a structure that would interact with other molecules to help them react to produce a duplicate. This is a biological enzyme. The current hypothesis is that early life was just RNA. RNA is a carrier of genetic information, but also can be an enzyme. Common examples are ribosomes, which read the genetic code and make all our proteins from that code, and self-splicing introns. This early RNA was probably able to produce copies of itself. This is life. We see certain molecules important for life, such as a sugar molecule, as being meaningful and special. However, as far as nature is concerned it's not. Take a deck of cards. If you were to shuffle them up, they appear disordered, but that's only because we don't give that particular order a meaning. It's just as probable to get that particular order as it is to get them Ace, king, queen, jack, etc. So basically, life will eventually happen given a long enough period of time. It's inevitable. Life flourished on Earth. Given another very similar system, it's highly probable life was also present there at some point.
greendestiny 19y ago
I think its a big deal. I think in many fields of science we are in danger of over fitting our theories because of our limited perspective. We've never discovered life on another planet, but we think its probably out there and thats enough? I just cannot understand that complacency.

by jey 19y ago

mberning 19y ago

I think there has been due diligence in asking the question "Did Mars have a significant period in it's history that it could have been habitable?". The answer to that question is "yes"; data suggest that Mars had a significant wet period. There are no bounds on what we might find if we can scrape a way the first few feet of sediment.

ingenium 19y ago

Mars almost certainly doesn't have life anymore, except maybe underground or in caves or something. The thing is that Mars used to be very similar to Earth, and it's even been suggested that life was seeded on Earth from Mars. What they are looking for is signs that Mars had life at some point in the past, because it would prove that life is not something that is unique and special to Earth. Also, I would be very curious how Martian life differed from life on Earth on a molecular level. I'd be willing to bet they were based on the same principles, but diverged pretty quickly. For example, they may not use the structure of the amino acid to produce protein, which is: H NH3-C-COOH | functional group If they did, they probably don't use the same codon code to present them in RNA or have the same functional groups that all Earth based life does. I'm certain there is life places other than Earth, but the question is what does that life look like? It may not even remotely resemble Earth based life. Finding life on Mars might give us a clue about what types of things to look for to identify life elsewhere.

asdflkj 19y ago
>I'm certain there is life places other than Earth, Any evidence for that? Edit: this is my pet peeve, and I'm still peeved, so I'll write some more. Nobody has any idea how probable the appearance of life is. Nobody even has an idea how it happened. The only thing we do know about that probability is that it's very low, since we haven't been able to observe life anywhere. Just how low is anyone's guess. It could be 1/(number of particles in the universe * googolplex). Or it could be much lower still. My other pet peeve is singularity. If you show an 19th century man our world and give him the definition of singularity, he'll tell you it already happened. That's because it's totally meaningless, and essentially amounts to this: "singularity is when technological progress goes so fast, that, like, dude, totally". There, now I feel better.
- DanielBMarkham 19y ago
  Just playing devil's advocate here, we're alive, aren't we? So the odds can't be much less than 1/(number of planets in the universe) As for the singularity, I believe the point is the nature of being a human will change. The 19th century man will fit into our world just fine. A "regular" man might not fit into a world where we're all part cyborgs. You are correct in that it's the same unknowable impenetrable future state for us and the 19th century guy, but the idea is that the nature of change will be different in the next 100 years than it ever has been -- because it deals with what it means to be human. The Fermi Paradox, Drake Equation, and the quest for life is one of my pet subjects. I like it because it is pseudo-science -- and I mean that in a good way. We simply have no means of actually performing experiments, since our knowledge of life consists of just one example for a brief period of time. I am tempted to think that life is just about everywhere in the universe, but heck if I know. If there is life everywhere, then where is everybody?
  - deleted 19y ago
    [deleted]
  - asdflkj 19y ago
    >we're alive, aren't we? So the odds can't be much less than 1/(number of planets in the universe) That argument takes for granted that the probability space comprises only the things in our observable universe. In other words, it claims that there doesn't exist anything that we don't already know about. That's a false premise. re: singularity. I think we are already part-cyborgs. For all practical purposes, Internet is a part of me--it's a sense organ. Ask yourself, what would you rather lose: your sense of hearing, or the technologies of the last 100 years? For me, it's the former, any day of the week. What it means to be human changes continuously, and has been changing since before we were officially human. Now it's changing faster than ever before, but it changed faster than ever before at almost every point in human history.
    - DanielBMarkham 19y ago
      "In other words, it claims that there doesn't exist anything that we don't already know about." -- that's not a false premise, that's the basis for science. I can only deal with things I can observe. If you put 4 black balls and one white ball into a bag and ask me the chances of drawing a white ball, it's 1/5. If you then say, "hey -- but I really put 9 black balls in there. Your math is wrong" that's not much in the way of an argument. We measure and calculate those things we can observe. Yes, one could speculate on non-observable things. But that's a game that has no end. We are conceptually part cyborgs. I think there will be a line that is crossed, perhaps in our lifetime, where the average person will be physically part cyborg. No matter how you measure it, that's a change of a different nature than simple discovery and invention. I think you are muddling the point a bit. One of the reasons the Fermi Paradox and Drake Equation are so interesting to me is that they rely on speculation. While I think the minimum is 1/(number of planets), who knows what that number is? And for all the other terms in the Drake Equation, you're just pulling numbers out of the air. It's as much a religion as science. Fascinating stuff, both from a science angle and as an observation of human nature.

ivankirigin 19y ago

We have one sample of life in the universe. Life on Mars would mean two. The difference from a scientific perspective is HUGE.

jey 19y ago
Yes, I fully agree. My question is why we should expect the probability of there being life on Mars to be appreciably above zero. It sounds like wishful thinking. As far as we know, life is not something that happens often nor easily, and there isn't any significant indication that there's life on Mars. So far it seems like we've picked our favorite hypothesis (that there's life on Mars) and are now scurrying around looking for any bits of evidence to support it. "Oooh look, there's some water! And some silica!" I'll avoid drawing the obvious comparison to creationism. Oops, too late. ;)
- ingenium 19y ago
  Life actually is pretty common I think. The simplest definition of life would be molecules that replicate. An example of an arguably form of life in space can be found at http://www.sciencedaily.com/releases/2007/08/070814150630.htm http://www.sciencedaily.com/releases/2007/08/070814150630.ht... When you look at the way evolution works, it becomes clear that there is life elsewhere. Let's take a set of atoms. When they're bombarded with energy they react with each other and form compounds. While predictable, there is a slight amount of randomness in this. Eventually, one of these will be able to replicate itself. A simple example is a structure that would interact with other molecules to help them react to produce a duplicate. This is a biological enzyme. The current hypothesis is that early life was just RNA. RNA is a carrier of genetic information, but also can be an enzyme. Common examples are ribosomes, which read the genetic code and make all our proteins from that code, and self-splicing introns. This early RNA was probably able to produce copies of itself. This is life. We see certain molecules important for life, such as a sugar molecule, as being meaningful and special. However, as far as nature is concerned it's not. Take a deck of cards. If you were to shuffle them up, they appear disordered, but that's only because we don't give that particular order a meaning. It's just as probable to get that particular order as it is to get them Ace, king, queen, jack, etc. So basically, life will eventually happen given a long enough period of time. It's inevitable. Life flourished on Earth. Given another very similar system, it's highly probable life was also present there at some point.

greendestiny 19y ago

I think its a big deal. I think in many fields of science we are in danger of over fitting our theories because of our limited perspective. We've never discovered life on another planet, but we think its probably out there and thats enough? I just cannot understand that complacency.