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One argument against the proposition: these very old stars have low metallicity. If life requires chemistry with elements above lithium in atomic number, it mi

One argument against the proposition: these very old stars have low metallicity. If life requires chemistry with elements above lithium in atomic number, it might be more rare around first-generation stars.

mercurialshark 11y ago
I'm always surprised this isn't discussed more or at least a variable to consider among others for updating the Drake Equation.
- lomnakkus 11y ago
  Personally, the Drake Equation has always seemed more than a little silly to me -- in that -- the plausible range of most of the parameters means that you can get pretty much any result you want. Don't get me wrong, it's a fine thing to ponder and think about all the involved variables and probabilities, but I wouldn't take it very seriously as an actual estimate of anything meaningful.
  - ethbro 11y ago
    When you don't know a lot, estimates have wide bounds. That doesn't diminish the importance of trying to logically construct a formula for establishing bounds. They might not be useful today, but you've got to start somewhere.
    - lomnakkus 11y ago
      Sure, but we might want try to at least constrain the parameters with better (verifiable!) bounds and perhaps even modify the equation occasionally when we learn more -- as we have done (learn, that is) since it was proposed. I should make clear that I wasn't disagreeing with mercurialshark, per se. As I said: It's certainly a good thing to think about these things, but... :) EDIT: Assuming it generally agrees with observed facts, a good sign for any scientific theory is how much it constrains the explanation/solution space. (Paraphrased, obviously. For the life of me I cannot remember who said this. Perhaps David Deutsch?) I don't think the Drake Equation adequately constrains the solution/explanation space.
      - noselasd 11y ago
        We do constrain the Drake equation when we know more. It's just that we don't know a lot. We have come to know the number of stars around pretty well - at least in our galaxy. Thanks to Kepler and other exoplanet hunters, we know know alot more about the number of planets. These findings are used to constrain the Drake equation. The rest of the parameters we don't know much about, yet.
  - IndianAstronaut 11y ago
    Especially considering we have a sample size of one, possibly two if you count Mars as a potential place of habitability. I would hold judgement till we explore Europa. Depending on what we find there life may or may not be common in the universe.
    - danieltillett 11y ago
      All this will tell us is that life can survive the trip to Mars or Europa. We already know this to be the case ( microbes are tough) and asteroid strikes provide the means of getting Earth life to these planets/ moons. At this point I would be more surprised if we don't find microbial life in the solar system outside of Earth.
- Wingman4l7 11y ago
  Yes; I've often wondered about the potential existence of planets with an insufficient quantity of rare earth metals, and if that renders them basically "inhospitable" to high tech civilization.
  - erikpukinskis 11y ago
    Why rare earth metals specifically?
    - Wingman4l7 11y ago
      They're used for a whole host of technologies -- doping semiconductors, magnets, lens coatings, metal alloys, etc.
  - dogma1138 11y ago
    Life also has to be on dry land and pretty similar in to us as far as sensory capabilities go to get any where. If you can't see you aren't going to develop laser, if you live under water you won't have fire, heck even hands are required for fine tool making so it's unlikely that we'll have space elephants or squids...
  - daveguy 11y ago
    Rare earth metals are a very specific set of elements. If you are talking "nothing above lithium" that means only hydrogen helium and lithium. AKA no carbon oxygen nitrogen (or silicon).
Retric 11y ago
Solar wind has a fairly large effect on plant formation so even relatively early stars are likely to have some rocky inner planets. Granted, not first generation stars, but large stars can go nova in as little as 3 million years making the 'first' gen stars a very short period.
JetSetWilly 11y ago
Centauri Dreams covered this point well: > Working with Alak Ray (Tata Institute of Fundamental Research, Mumbai), Di Stefano points out that we have found low-metallicity stars known to have planets elsewhere in the galaxy. And while we can couple the occurrence of Jupiter-class planets with stars that have higher metallicity, there seems to be no such correlation when we’re dealing with smaller, rocky worlds like the Earth. Perhaps, then, we shouldn’t dismiss planets in globular clusters. http://www.centauri-dreams.org/?p=34775 http://www.centauri-dreams.org/?p=34775
- Udo 11y ago
  There is still a lot about the formation of galaxies and star systems that we don't know. The reason why we assume a lower probability for rocky planets in globular clusters is the general environment of the typical cluster: a small population of slow-burning early-generation stars with no appreciable interstellar dust clouds in between them. If you compare that to low-metallicity stars in the galaxy proper, there are reasons why those might have planets that are not easily afforded to star systems located in globular clusters. Our galaxy is rich in dust and gas clouds that are also inhomogeneous. For example, a metal-poor star may be born out of a low-metal gas cloud and then attract a metal-rich dust disc later. These things are expected to happen a lot less often in globular clusters.
  - iofj 11y ago
    There's the reverse problem as well. If life develops by itself when it has (chemically) the chance ... then where is it ? Our sun is a third generation star (meaning some sun went nova, recoalesced into another sun, went nova, recoalesced in our sun and ignited, and that was 3+ billion years ago). Our sun is not a particularly early third generation star. Given that it would take a civilization about a billion years to spread through the galaxy to all liveable planets ... some civilization should have done that up to 4-5 billion years ago. If life can happen in 2nd generation stars as well, it should have happened 6-8 billion years ago. Obviously this hasn't happened. I only see 3 reasonable explanations: 1) Drake equation is too optimistic. By a huge factor (2-300 million times too optimistic) 2) It's not a problem, because civilizations kill themselves before doing interstellar travel and while we are on the way to doing that but not quite there yet. 3) There's something we don't know

mercurialshark 11y ago

I'm always surprised this isn't discussed more or at least a variable to consider among others for updating the Drake Equation.

lomnakkus 11y ago
Personally, the Drake Equation has always seemed more than a little silly to me -- in that -- the plausible range of most of the parameters means that you can get pretty much any result you want. Don't get me wrong, it's a fine thing to ponder and think about all the involved variables and probabilities, but I wouldn't take it very seriously as an actual estimate of anything meaningful.
- ethbro 11y ago
  When you don't know a lot, estimates have wide bounds. That doesn't diminish the importance of trying to logically construct a formula for establishing bounds. They might not be useful today, but you've got to start somewhere.
  - lomnakkus 11y ago
    Sure, but we might want try to at least constrain the parameters with better (verifiable!) bounds and perhaps even modify the equation occasionally when we learn more -- as we have done (learn, that is) since it was proposed. I should make clear that I wasn't disagreeing with mercurialshark, per se. As I said: It's certainly a good thing to think about these things, but... :) EDIT: Assuming it generally agrees with observed facts, a good sign for any scientific theory is how much it constrains the explanation/solution space. (Paraphrased, obviously. For the life of me I cannot remember who said this. Perhaps David Deutsch?) I don't think the Drake Equation adequately constrains the solution/explanation space.
    - noselasd 11y ago
      We do constrain the Drake equation when we know more. It's just that we don't know a lot. We have come to know the number of stars around pretty well - at least in our galaxy. Thanks to Kepler and other exoplanet hunters, we know know alot more about the number of planets. These findings are used to constrain the Drake equation. The rest of the parameters we don't know much about, yet.
- IndianAstronaut 11y ago
  Especially considering we have a sample size of one, possibly two if you count Mars as a potential place of habitability. I would hold judgement till we explore Europa. Depending on what we find there life may or may not be common in the universe.
  - danieltillett 11y ago
    All this will tell us is that life can survive the trip to Mars or Europa. We already know this to be the case ( microbes are tough) and asteroid strikes provide the means of getting Earth life to these planets/ moons. At this point I would be more surprised if we don't find microbial life in the solar system outside of Earth.
Wingman4l7 11y ago
Yes; I've often wondered about the potential existence of planets with an insufficient quantity of rare earth metals, and if that renders them basically "inhospitable" to high tech civilization.
- erikpukinskis 11y ago
  Why rare earth metals specifically?
  - Wingman4l7 11y ago
    They're used for a whole host of technologies -- doping semiconductors, magnets, lens coatings, metal alloys, etc.
- dogma1138 11y ago
  Life also has to be on dry land and pretty similar in to us as far as sensory capabilities go to get any where. If you can't see you aren't going to develop laser, if you live under water you won't have fire, heck even hands are required for fine tool making so it's unlikely that we'll have space elephants or squids...
- daveguy 11y ago
  Rare earth metals are a very specific set of elements. If you are talking "nothing above lithium" that means only hydrogen helium and lithium. AKA no carbon oxygen nitrogen (or silicon).

Retric 11y ago

Solar wind has a fairly large effect on plant formation so even relatively early stars are likely to have some rocky inner planets. Granted, not first generation stars, but large stars can go nova in as little as 3 million years making the 'first' gen stars a very short period.

JetSetWilly 11y ago

Centauri Dreams covered this point well: > Working with Alak Ray (Tata Institute of Fundamental Research, Mumbai), Di Stefano points out that we have found low-metallicity stars known to have planets elsewhere in the galaxy. And while we can couple the occurrence of Jupiter-class planets with stars that have higher metallicity, there seems to be no such correlation when we’re dealing with smaller, rocky worlds like the Earth. Perhaps, then, we shouldn’t dismiss planets in globular clusters. http://www.centauri-dreams.org/?p=34775 http://www.centauri-dreams.org/?p=34775

Udo 11y ago
There is still a lot about the formation of galaxies and star systems that we don't know. The reason why we assume a lower probability for rocky planets in globular clusters is the general environment of the typical cluster: a small population of slow-burning early-generation stars with no appreciable interstellar dust clouds in between them. If you compare that to low-metallicity stars in the galaxy proper, there are reasons why those might have planets that are not easily afforded to star systems located in globular clusters. Our galaxy is rich in dust and gas clouds that are also inhomogeneous. For example, a metal-poor star may be born out of a low-metal gas cloud and then attract a metal-rich dust disc later. These things are expected to happen a lot less often in globular clusters.
- iofj 11y ago
  There's the reverse problem as well. If life develops by itself when it has (chemically) the chance ... then where is it ? Our sun is a third generation star (meaning some sun went nova, recoalesced into another sun, went nova, recoalesced in our sun and ignited, and that was 3+ billion years ago). Our sun is not a particularly early third generation star. Given that it would take a civilization about a billion years to spread through the galaxy to all liveable planets ... some civilization should have done that up to 4-5 billion years ago. If life can happen in 2nd generation stars as well, it should have happened 6-8 billion years ago. Obviously this hasn't happened. I only see 3 reasonable explanations: 1) Drake equation is too optimistic. By a huge factor (2-300 million times too optimistic) 2) It's not a problem, because civilizations kill themselves before doing interstellar travel and while we are on the way to doing that but not quite there yet. 3) There's something we don't know