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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

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
  - dogma1138 11y ago
    4) Reapers But yeah "We are first, we are rare or we are screwed..." Pretty much sums it up if there are "great filters" to life we really don't understand them yet.
    - iofj 11y ago
      The thing is, it would be very surprising if we are first. Certainly wouldn't fit the Drake equation.
      - dogma1138 11y ago
        https://xkcd.com/384/ https://xkcd.com/384/ The biggest problem with the Drake equation is that we are using a sample of one, it also doesn't take into account great filters that will prevent the development of intelligent life, technological civilizations and interstellar ones. Our technology jumped from sticks and stones to interplanetary rockets in 10,000 or so years after sticking to those sticks and stones for about 200,000 - 250,000 years. We still have had people living in the Stone Age during ww2 and some still do today. We probably know less about how a civilization might develop into a technological one than we know about how life can evolve.
        marshray 11y ago
        Just out of curiosity, why do you mention WWII specifically as a time when some people were living in the stone age?
        dogma1138 11y ago
        Because the war in the pacific had quite an impact some of them. https://en.m.wikipedia.org/wiki/Cargo_cult https://en.m.wikipedia.org/wiki/Cargo_cult Do while we were building rockets and going into space some of us were making airplanes out of straw to get more gifts from thier ancestors.

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
- dogma1138 11y ago
  4) Reapers But yeah "We are first, we are rare or we are screwed..." Pretty much sums it up if there are "great filters" to life we really don't understand them yet.
  - iofj 11y ago
    The thing is, it would be very surprising if we are first. Certainly wouldn't fit the Drake equation.
    - dogma1138 11y ago
      https://xkcd.com/384/ https://xkcd.com/384/ The biggest problem with the Drake equation is that we are using a sample of one, it also doesn't take into account great filters that will prevent the development of intelligent life, technological civilizations and interstellar ones. Our technology jumped from sticks and stones to interplanetary rockets in 10,000 or so years after sticking to those sticks and stones for about 200,000 - 250,000 years. We still have had people living in the Stone Age during ww2 and some still do today. We probably know less about how a civilization might develop into a technological one than we know about how life can evolve.
      - marshray 11y ago
        Just out of curiosity, why do you mention WWII specifically as a time when some people were living in the stone age?
        dogma1138 11y ago
        Because the war in the pacific had quite an impact some of them. https://en.m.wikipedia.org/wiki/Cargo_cult https://en.m.wikipedia.org/wiki/Cargo_cult Do while we were building rockets and going into space some of us were making airplanes out of straw to get more gifts from thier ancestors.