5 ms·

Why do you say gravity is important for organelles? At those length scales other forces are MUCH more important than gravity.

saagarjha 7y ago
Gravity is important for heavy elements to cluster in one place in sufficient concentrations to form organelles.
- krastanov 7y ago
  Excuse my language, but I want to stress how preposterous this statement is: this is complete and utter nonsense. Gravity is way more than 10^10 times weaker than electromagnetism at this scale. Unless you mean "gravity is important to make planets, and planets are where we have observed life", in which case you are stretching the meaning of this expression to a meaningless level.
  - soulofmischief 7y ago
    Here you go: https://www.hindawi.com/journals/bmri/2015/863075/ https://www.hindawi.com/journals/bmri/2015/863075/ I am not being abstract. Beyond molecular chemistry, gravity and electromagnetism are the dominant ambient forces. We are still learning of the relationship between gravity and QM. What is complete and utter nonsense is refuting a hypothesis without understanding it.
    - eesmith 7y ago
      Okay, I read it. It's an editorial. It says nothing about how gravity is required "for heavy elements to cluster in one place in sufficient concentrations to form organelles". For the matter, it says nothing about heavy elements.
      - pharrington 7y ago
        https://www.nasa.gov/mission_pages/station/research/cciss_feature.html https://www.nasa.gov/mission_pages/station/research/cciss_fe... https://en.wikipedia.org/wiki/Hemodynamics https://en.wikipedia.org/wiki/Hemodynamics etc. Yes, gravity is, by far, the weakest force. None-the-less, it is a force, and definitely effects all sorts of things at all scales.
        petschge 7y ago
        While technically present at all scales, gravity is so weak that you can ignore it until you get to pretty large scales. Meters or so. An ant barely feels gravity, a bacterium or a single cell don't even know it is there.
        pharrington 7y ago
        If you wanna go down that rabbit hole... one must be as precise as possible when estimating.
        soulofmischief 7y ago
        What does it mean to "feel" gravity? I assure you the ant's biological systems would undergo many changes over generations in the absence of gravity in order to reach homeostasis. A bacterium can't feel anything but did I mention single-celled organisms? No, I mentioned organelles. You are arguing against a straw-man. Furthermore you are completely ignoring the effect of gravitational perturbations on emergent structures. These things don't necessarily "iron out", and if they do, we have not yet ascertained at what level and via what mechanism. You are confusing an object's ability to produce gravity with its propensity for interacting with gravity.
        ceejayoz 7y ago
        > A bacterium can't feel anything but did I mention single-celled organisms? No, I mentioned organelles. Given that mitochondria are almost certainly descended from captured bacteria, that's an odd quibble.
    - jcranmer 7y ago
      The cell is not a natural homogeneous mixture obeying the laws of free energy. It is actually a densely packed collection of mechanisms designed to subvert free energy and selective cause otherwise improbable reactions to occur. It ought not to be a surprise that some of those mechanisms do not work so well outside the standard uniform gravitational field we experience. But that is not to say that there isn't another set of mechanisms that could work without the influence of gravity. You can see this in parallel with human construction: stairs don't work so well without gravity, but ladders work perfectly fine.
      - soulofmischief 7y ago
        > It ought not to be a surprise that some of those mechanisms do not work so well outside the standard uniform gravitational field we experience This is called a dependency. So you agree with my initial proposition. > But that is not to say that there isn't another set of mechanisms that could work without the influence of gravity As I addressed in another post, this is orthogonal to the discussion because we are talking about the universe the way it is, not the way it could be; If we remove gravity from the equation, we don't even get past the big bang and forming systems from uneven matter distribution.
        jcranmer 7y ago
        Your original proposition is "[gravity is] required for [...] chemical reactions in our organelles." I am explicitly disagreeing that gravity is required for such reactions. Your own source doesn't back up that statement--it suggests that the microstructure (in addition to the more obvious structure of the intercellular matrix) of cells is influenced by gravity, which is itself a rather different statement. Influence is a very different thing from requirement. Furthermore, I should point out that our experience that life can survive quite well outside of the normal gravitational field is itself sufficient disproof of your proposition. After all, our mitochondria don't go "Wait! There's no gravity! How am I supposed to Krebs cycle now?"
        soulofmischief 7y ago
  - saagarjha 7y ago
    > Unless you mean "gravity is important to make planets, and planets are where we have observed life" I did.

saagarjha 7y ago

Gravity is important for heavy elements to cluster in one place in sufficient concentrations to form organelles.

krastanov 7y ago
Excuse my language, but I want to stress how preposterous this statement is: this is complete and utter nonsense. Gravity is way more than 10^10 times weaker than electromagnetism at this scale. Unless you mean "gravity is important to make planets, and planets are where we have observed life", in which case you are stretching the meaning of this expression to a meaningless level.
- soulofmischief 7y ago
  Here you go: https://www.hindawi.com/journals/bmri/2015/863075/ https://www.hindawi.com/journals/bmri/2015/863075/ I am not being abstract. Beyond molecular chemistry, gravity and electromagnetism are the dominant ambient forces. We are still learning of the relationship between gravity and QM. What is complete and utter nonsense is refuting a hypothesis without understanding it.
  - eesmith 7y ago
    Okay, I read it. It's an editorial. It says nothing about how gravity is required "for heavy elements to cluster in one place in sufficient concentrations to form organelles". For the matter, it says nothing about heavy elements.
    - pharrington 7y ago
      https://www.nasa.gov/mission_pages/station/research/cciss_feature.html https://www.nasa.gov/mission_pages/station/research/cciss_fe... https://en.wikipedia.org/wiki/Hemodynamics https://en.wikipedia.org/wiki/Hemodynamics etc. Yes, gravity is, by far, the weakest force. None-the-less, it is a force, and definitely effects all sorts of things at all scales.
      - petschge 7y ago
        While technically present at all scales, gravity is so weak that you can ignore it until you get to pretty large scales. Meters or so. An ant barely feels gravity, a bacterium or a single cell don't even know it is there.
        pharrington 7y ago
        If you wanna go down that rabbit hole... one must be as precise as possible when estimating.
        soulofmischief 7y ago
        What does it mean to "feel" gravity? I assure you the ant's biological systems would undergo many changes over generations in the absence of gravity in order to reach homeostasis. A bacterium can't feel anything but did I mention single-celled organisms? No, I mentioned organelles. You are arguing against a straw-man. Furthermore you are completely ignoring the effect of gravitational perturbations on emergent structures. These things don't necessarily "iron out", and if they do, we have not yet ascertained at what level and via what mechanism. You are confusing an object's ability to produce gravity with its propensity for interacting with gravity.
        ceejayoz 7y ago
        > A bacterium can't feel anything but did I mention single-celled organisms? No, I mentioned organelles. Given that mitochondria are almost certainly descended from captured bacteria, that's an odd quibble.
  - jcranmer 7y ago
    The cell is not a natural homogeneous mixture obeying the laws of free energy. It is actually a densely packed collection of mechanisms designed to subvert free energy and selective cause otherwise improbable reactions to occur. It ought not to be a surprise that some of those mechanisms do not work so well outside the standard uniform gravitational field we experience. But that is not to say that there isn't another set of mechanisms that could work without the influence of gravity. You can see this in parallel with human construction: stairs don't work so well without gravity, but ladders work perfectly fine.
    - soulofmischief 7y ago
      > It ought not to be a surprise that some of those mechanisms do not work so well outside the standard uniform gravitational field we experience This is called a dependency. So you agree with my initial proposition. > But that is not to say that there isn't another set of mechanisms that could work without the influence of gravity As I addressed in another post, this is orthogonal to the discussion because we are talking about the universe the way it is, not the way it could be; If we remove gravity from the equation, we don't even get past the big bang and forming systems from uneven matter distribution.
      - jcranmer 7y ago
        Your original proposition is "[gravity is] required for [...] chemical reactions in our organelles." I am explicitly disagreeing that gravity is required for such reactions. Your own source doesn't back up that statement--it suggests that the microstructure (in addition to the more obvious structure of the intercellular matrix) of cells is influenced by gravity, which is itself a rather different statement. Influence is a very different thing from requirement. Furthermore, I should point out that our experience that life can survive quite well outside of the normal gravitational field is itself sufficient disproof of your proposition. After all, our mitochondria don't go "Wait! There's no gravity! How am I supposed to Krebs cycle now?"
        soulofmischief 7y ago
- saagarjha 7y ago
  > Unless you mean "gravity is important to make planets, and planets are where we have observed life" I did.