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Life on planet Gliese?

Discussion in 'Science & Technology' started by Disgustipated, Sep 29, 2010.

  1. TheLastOne36

    TheLastOne36 Deity

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    I agree with Uppi. It is certainly possible theoretically, so I don't see why it can't be done with future technological advancements.
     
  2. Bluemofia

    Bluemofia F=ma

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    ...

    So we should drop all scientific endeavors to scour every square inch of the planet, test every last animal of every jungle, sample every milliliter of water to be absolutely 100% sure that there are zero super-germs that threaten the human race?

    Following that, regularly repeating every few years of course to account for mutations that might generate lethal super-germs, we should scan the skies to be able to account for every single atom of every single cubic centimeter of all of the solar system, followed by entering all of the gathered data into a massive simulation database to be able to predict all possible future trajectories of them?

    Sorry, I think proposing that all other endeavors should be dropped in favor of refining what is important to the survival of the human race to 100% accuracy is absurd.

    Colonizing other planets BTW is also relevant to the survival of our species. :rolleyes: It is very relevant considering how it is what determines whether or not we survive in the long run at all. And you call me a hypocrite.


    Of course. But that does not mean in any way we should scrap all other projects in favor of it, as you seem to be suggesting. I personally think scrapping things like politically motivated wars is a better choice, rather than scrapping other science projects. :rolleyes:


    Did a quick glance at it, and it seems to be very well put together, being especially reader friendly. Good find. :)

    Summary of the article:
    1. Red Dwarves, due to their small masses and the convection of material from surface to core, allow more stable habitable zones due to less change in luminosity and a larger continuous habitable zone, allowing for 100 to 1000 billion year habitability. Planet habitability lifetimes are primarily restricted to planetary conditions, rather than stellar conditions.
    2. The inner edge of the habitable zone is defined as where H2O decomposition is enough to destroy the negative feedback mechanism of CO2 cycling through oceans and crust via volcanism, carbonic acid, and calcium carbonate formation, and the hydrogen generated from decomposition lost to outer space. (FAR FAR better than the luminosity required to keep water from evaporating off)
    3. A 100 mbar CO2 atmosphere (0.1 ATM, or about twice the average atmospheric pressure of Mars) is sufficient to prevent the atmosphere from freezing out via convection heat transfer.
    4. Different values for spin to orbit resonances other than 1:1 ratios may be present, (technically Mercury's 3:2 ratio is also tidal locking) which would further reduce the barriers presented by being close to the star.
    5. Habitable zones are further modified by albedo of planet. Planets with a high water content will have a higher albedo, and the inner edge of the habitable zone will be shifted further inwards.
    6. Lack of UV light from red dwarves will allow unusual atmospheres (compared to Earth) to be stable, allowing CH4 and N2O to play significant roles in the greenhouse effect, and also decreasing the role of the CO2 condensation limit, extending the outer edge of the habitable zone further outward.
    7. The variability of luminosities of red dwarves on short time scales are smoothed by a multitude of factors. The presence of a 1 bar atmosphere will prevent atmospheric collapse even if solar intensity is reduced by 40% for a month. The tidal locking mechanism also stabilizes the axial tilt of the planet, preventing extreme climate variations due to changes of axial tilt.
    8. Protoplanetary disks of significant masses relative to the star are common around red dwarves in star forming regions, and thus a high likelihood exists of planets forming within them.
    9. Habitability across the terminator (day-night divide) may be hampered by high convection winds. However, they are negated by the large area, reducing the amplitude.
    10. Clouds transported across the terminator may reduce the sunlight available to the plants there, but will partially shield against solar flares.
    11. Taking account the multitude of factors, assuming a modest sized ocean, sufficiently massive planet, and a sufficiently large period of time, there is no reason to assume the planets cannot be habitable.
    12. Solar flares may be a potential problem for planets in the habitable zone, as they may briefly increase in brightness significantly, followed by a CME. However, of the stars examined, the low mass M stars have a low rate of becoming flare stars, with the rate increasing as mass increases, peaking at a M5.5 to M7 stars, and dropping for K stars.
    13. Mass loss rate due to solar flares, CMEs, and solar wind may cause a planet to move out of the habitable zone. However, the mass loss rate of a red dwarf is far lower than the mass loss rate of the sun; the sun requires a few hundred billion years to lose enough mass to push a planet out of the Habitable Zone from conservation of Angular momentum. Planets around a red dwarf will remain in the habitable zone, so any loss of habitability will be due to geologic, as opposed to stellar factors.
    14. "Planetary rotation periods within the M dwarf habitability zone are estimated to be between 10 and 100 days. These rotation rates, though slower than that of
    Earth, will still produce strong Coriolis forces in 100–1,000-km-deep core fluid layers. Thus, in terms of dynamo theory (Stevenson, 2003), tidally locked planets orbiting M dwarfs are viable candidates for core dynamos."
    15. Atmosphere loss via Jeans escape (molecules reach escape velocity due to thermal distribution) only applies to Hydrogen and Helium is considered a negligible factor in atmospheric depletion. Hydrodynamic escape mechanisms (sort of a vacuum powered escape from large amounts of hydrogen escaping all at once, and sucking heavier elements out) are UV dependent, and may play a significant role in its early phase of its life prior to stabilizing. Dissociative recombination (ionized molecules capturing high energy electrons, and then acquiring enough energy to escape), ion escape (electric fields of solar wind accelerating ionized molecules out), and sputtering (brute force knocking molecules out of the atmosphere) are dependent on solar wind strength, and UV strength for the former two. More research is required.


    And then it goes onto how they need to do more research to be able to better refine their models.

    However, things are looking very good for habitable planets, so long as they have enough water for heat transfer. Only potential problem is the solar flares in M5-M7 stars, and that dies down after 1-3 billion years.

    And yet you completely ignored what I just said. Power consumption is not static. As in, we generate more power as time goes on. As in, those values relatively speaking will become smaller and smaller as time goes on.

    I'm not arguing that the energy cost is going to decrease, but the percentage of energy relative to what we produce in a period of time is going to decrease.


    With the average density of the interstellar medium (including molecular clouds and nebula and stuff) to be 1 atom per cubic centimeter, and the local interstellar medium to be 0.001 atoms per cubic centimeter... And 99% of it is Hydrogen and Helium gas.

    The ones not locked up in gas is in the form of dust, the largest of which is a fraction of a micron in size.

    I'm sorry, you're not going to find any pebble sized objects. Those are far too large, and the materials too sparse to stand a reasonable chance of forming. (Most things are not afraid of a few hydrogen pebbles, if the density somehow is freakishly anomalously high, as they have no structural integrity)

    ... Extremophiles are only called extremophiles because the conditions are unusual on Earth. In unusual conditions, you're not going to have a lot of chances to develop, compared to usual conditions by definition.

    Note that no oxygen utilizing life formed until after oxygen was in great abundance (and not to mention slaughtering everything else that didn't develop oxygen resistance), despite how much energy oxygen can generate. The most common of environments is going to allow the most development to take place, as your experiment sample size is far larger.
     
  3. El_Machinae

    El_Machinae Colour vision since 2018 Retired Moderator

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    Oh, I'll be terribly excited. I just don't think it would change my life very much. I don't know if I'd do anything differently than I would have. It might create more social support for research into space development, and thus get us into space more quickly. But I don't actually know.

    I'm already pretty pro-space-development, though, so maybe I'm an exception to how people's attitudes will change.
     
  4. PiTiFUL

    PiTiFUL Warlord

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    Funding got axed.

    Extremophiles are extremophiles because they survive outside of the optimum oxygen cycle of life. Titan is a prime example of an extremophile enviroment, it has weather, liquid on its surface, rain even, its the closest thing to earth in our solar system with the possibility of a truly alien life, evolved outside of the optimum oxygen environment and at best will produce microbes... wheres the link I asked for? There isnt one because there isnt a biologist who thinks a complex animal like life form can develope without oxygen.

    In the first sentence you claim these values will become smaller and you follow up and say the energy cost isnt going to change!?! Make up your mind. I've stated nothing about how we will end up generating that kind of power, thats an entirely different set of problems, all I'm stating is the power required.

    EDIT; ok I think I understand what your getting at, you are talking efficiency, correct? so what your saying is that as we increase efficiency we increase energy output? Problem is still power output, no matter how efficiently we can generate power, you are still not generating enough power even at 100% efficiency. On earth this isnt such a big deal because we just build more power plants, as many as we need, with a spaceship that is not possible. A correct analogy would be, can we supply the entire power consumption of the USA with one single power plant, no, and even that fantasy power source would still take 431 years to accelerate my ship to 1\10th the speed of light.

    PS an atomic bomb is E=MC2 uncontrolled, in its purest form, we will not ever be able to generate power faster then the uncontrolled mass to energy conversion of a nuclear bomb. Once we apply control to the mass to energy conversion we slow it down, no matter how efficient it is, aka a nuclear reactor vs a nuclear bomb. So lets imagine a major scientific breakthru, we can create and utilize (as thrust) an atomic bombs total energy output in say one minute, thats far beyond even the theoretical fusion reactor. You can now accelerate my ship to 1\10th the speed of light in 1470 years.

    The energy output of an uncontrolled fusion reactor with a 4.4 million km circumference and a mass of 1.9891 x10 to 30 power kg is not relevant, read up on the energy used by plant life alone in one day, its mind boggling. Your antimatter calculation is off, antimatter could generate the power required with 10714 pounds or 5MT, thats using 1 pound of antimatter = 20 megatons as a base.

    Creating antimatter requires a massive amounts of energy itself, here Bluemofia can your "Power consumption is not static." argument be applied. I heard creating one teaspoon of antimatter would bankrupt the USA... this was before the US went bankrupt :)

    Actually I have grossly underestimated the mass of a generation ship. How many people do you need to have a viable genetic pool? then add some more as a safety factor multiply by 4 because they are going to breed during the trip and you can expect at least 4 generations to be alive at any point. So lets say 200 people to maintain a viable gene pool x 4, you need living quarters for 800 people plus all other nessesitys, hospital, school, recreation, mess halls, machine shops, storage ect, you need a greenhouse large enough to supply food and oxygen to 800 people, you need water to supply 800 people and the greenhouse for thousands of years, you need power source, engines, fuel... you need ships to land on the planet once you get there, equipment and supplies to get the colony going once you arrive, for safety you need double or more of everything you have for ship systems, because theres no home depots in intersteller space, and youll probably need a way to manufacture stuff from scratch, raw materials, forges mini factorys, in the end youre probably looking at millions of tons and just changed the power requirements by a factor of ten or more.
     
  5. uppi

    uppi Deity

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    It is relevant, as it puts some upper limit on the amount of power that we could theoretically collect. Of course you would need huge solid angle coverage, but you could wait longer than a millisecond.

    No, it's not, assuming your figure of 12500 PWh is correct. Pro tip: Stick to SI units, makes the whole thing easier.

    Anything involving antimatter is obviously only viable if we find some way to produce it more efficiently. The current antimatter production method is horribly inefficient, and there is no fundamental limit why it cannot be more efficient.


    But you're assuming 50 years old technology. Building a spaceship from steel would be incredibly stupid. You would really have to optimize it for weight. If we could build huge carbon nanostructures that factor of 10 could be easily compensated by material science alone.

    But its quite useless trying to make engineering estimates with current technology as we're not quite there yet. And to make engineering estimates with future technology is just wild guessing. But for your design the theoretical fuel/weight ratio is good enough that given enough technological advance it is just a matter of how much energy you sink in it.
     
  6. Perfection

    Perfection The Great Head.

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    Just one (probably want a couple more in case she kicks it)
     
  7. PiTiFUL

    PiTiFUL Warlord

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    Heh took me a bit to figure out what the heck I was looking at, then realized you plugged the information into E=MC2, so assuming 100% mass to energy conversion you get 500 metric ton, cool. The information I had then was bollocks and was out by a factor of 100. I got 12500 PWh based on this information... Accelerating one ton to one-tenth of the speed of light requires at least 125 billion kWh, and I assume this is at 100% efficiency.

    No argument there, but just on the subject of getting a generation ship to a habitable star its not relevant, we just assume we have it. Of course in practice it is a big deal because we arent leaving until we do have it, assuming its even possible. Also theres the problem of not just creating it, but containing it, heh imagine the containment structure and power needed to keep 500t of antimatter away from matter... and would we even want that much antimatter on our planet, if something went wrong, Praxis :eek: seems to me we would have to be able to create it as we need it in the ship itself, so now youll need to add an antimatter factory to the ship too, with its power consumption, mass and whatever raw materials it needs.

    Yup, scientific advancement in material is definatly one way we could help improve the possibility of star travel. But, its still going to have mass, and if we have to keep humans alive and safe and in sufficient quantity for a viable gene pool, a lot of mass, and thats the killer. The more you consider it, the more problems crop up, the more unlikely such an endeavor seems possible. Sure science can solve some issues but a lot of them are fundamental physical laws of nature, distance and time.
     
  8. uppi

    uppi Deity

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    Making antimatter on the ship itself defeats its purpose, because we would need energy to do this and there is no energy source in interstellar space, so we would need fuel for that and that's why we wanted antimatter in the first place.

    I think antimatter would best be produced in space, because space itself is already a good prepumping stage for the extreme high vacuum needed to store antimatter. I would imagine a lot of small producing facilities in space powered by solar radiation.

    Trapping antimatter could in principle be done without any energy consumption in, say, a magnetic trap, as long as there is no heating of the antimatter. If there is heating, cooling is needed, which will require energy. I don't think it could be done at the moment (although I do wonder how well a giant magneto-optical trap would work in space...should actually be pretty good), but we're working on that.


    But these do not make it impossible, just very difficult. And you never know what scientist will come up with in the next 100 years. If you told a scientist from 100 years ago, what we are capable of at the moment he'd say you're crazy.

    But I admit, there is the possibility that we will never get to another star, either because we find no way to do it, or because it would be so resource consuming that we're never going to do it.
     
  9. Perfection

    Perfection The Great Head.

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    Not really, I already know a vehicle that can transport enough humans to form a viable gene pool. It's called a Geo Metro
     
  10. Bluemofia

    Bluemofia F=ma

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    No, definition of extremophile is something that thrives, or even requires the extremes. This is not limited to oxygen, but includes high saline, high/low pH, high/low temperatures, etc.

    You don't understand that absence of proof is not proof of absence, citing lack of complex organisms on Earth with alternative biochemistries to oxygen as proof of lack of complex organisms without alternative biochemistries. You haven't found a rigorous article saying it is impossible explicitly. The one article you dug up was one that reverse engineered current molecules to find that those molecules cannot be formed without oxygen, and thus blanket stating that life as we know it cannot have evolved without oxygen.

    http://www.xenology.info/Xeno/8.0.htm
    http://www.xenology.info/Papers/Xenobiology.htm
    Biochemistries which utilize sulfur instead of oxygen are comparatively common on earth of the hypothetical biochemistries for complex living organisms. Another alternative suggested is chlorine, but that in itself runs into problems with the abundance problem, and therefore unlikely to exist in that regard (but not impossible).


    Are you deliberately misinterpreting my statements? (NOT efficiency. NOT physical energy requirements. RAW power generation and consumption. The US power consumption was 9TWh in 1900. Now it is obviously far higher.) You say we require 12500 PWh. Then you state that the amount is 431 years worth of US energy, and therefore impossible.

    The power consumption is not static. The US (and world) power consumption is projected to grow exponentially with time. It HAS grown exponentially with time. Eventually with the advancement of technology, 12500 PWh will be reduced to a smaller amount of time, say 400 years of energy, or 200 years, or even possibly 30 days worth long into the future. Power consumption is not static, and will grow over time. Eventually the 12500 PWh will become minuscule if trends continue, and that is when it will become feasible.

    The 12500 PWh to accelerate the ship becomes trivial as time goes on and power generation technology improves.


    Problem with your statement is that uncontrolled explosions are usually one of the most inefficient methods of producing energy (lots wasted in useless things like vibrating atoms, making buildings blow up, etc.). Generating incredible amounts of energy fast is a rather inefficient way of doing things, as energy is wasted. Ion engines are incredibly energy efficient, yet they are also incredibly weak in power.

    You also don't want all of that energy all at once, causing you to liquify under massive acceleration forces from all the energy released at once. The problem comes to controlling the reaction to run at an adequate rate. And a nice acceleration rate is at 1 g. Using safe accelerations, you can accomplish it in 35 days. How much energy you can generate to produce this becomes an engineering issue, rather than a physics issue.
     
  11. PiTiFUL

    PiTiFUL Warlord

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    So your backing up your view with a 30 year old book, which covers everything from alien sex to cosmic warfare, written by someone who has no education in biology and who frequently used SF authors as references? :lol: The picture of NCC-1701 on the cover is very apt because its mostly fiction. Heres some quotes from the author himself...

    "Xenology was current as of 1979, but the field has made 30 years of progress since then. The reader will find numerous omissions of facts and valuable references that have been published in the intervening years, and probably even a fair number of outright errors which were unknown at the time of writing."

    "The book contains some pretty speculative material in a few places, including material from speculative fact and science fiction writers when appropriate. But generally the text tries to stick to concepts and arguments that are grounded in some kind of precedent either in biology, technology, or the social sciences and the arts."

    riiiight... here if you got some time to burn is something from an actual biologist who doesnt use Ray Bradbury as a reference.

    http://www.stanford.edu/group/astrobiology/cgi-bin/?page_id=307


    Wouldnt the lasers in the magneto-optical trap be introducing matter (photons) into the antimatter? Heh was reading up on anti-matter, we have a long long way to go in that field and its still up in the air if its ever going to be feasible.
     
  12. Perfection

    Perfection The Great Head.

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    Why the hell do you think it needs to be 1/10th the speed of light anyways? Why can't it be say, 1/100th?
     
  13. J-man

    J-man Deity

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  14. El_Machinae

    El_Machinae Colour vision since 2018 Retired Moderator

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    They can't yet rule it out as a statistical anomaly.

    This story is SOoooo cool. I'm almost on pins with each new update.

    Because if you leave at 1/100th c, then I'm going to wait x number of years for the economic and technological progress to advance, and then buy a faster starship than yours, and then get to 'your' planet first! :mwaha:
     
  15. Olleus

    Olleus Deity

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    Well then why not go at 1/5th the speed of light rather than 1/10th?

    There is an optimum between waiting for technology to advance and getting a headstart. There is absolutely 0 reasons why that optimum is at 1/10th rather than 1/100th of the speed of light.
     
  16. El_Machinae

    El_Machinae Colour vision since 2018 Retired Moderator

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    It's just a numbers game, at that point, right? You're right, there's no reason for 1/10th to be the optimum. In fact, I expect that the optimum will be 90+% of c. Once you're going ~90% of c, it will be much tough for someone to scoop you.

    My main point is that I'm scooping Perfie's homesteading efforts.
     
  17. Haseri

    Haseri Emperor

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    Not sure, but I've seen the number 150 bounded around somewhere. Of course,t he more the merrier.

    I think arguing that something will never be possible is an act of futility. We could be heading for another technological revolution, where technology and society afterwards is radically changed in such ways that we cannot even begin to predict them, much like the industrial and digital revolutions.
     
  18. uppi

    uppi Deity

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    No, photons are not matter in that sense. Annihilation happens, when a particle meets its antiparticle, so to annihilate an antiproton you need a proton. Photons have no antiparticle (there are no antiphotons), so they can interact with matter and antimatter compounds. Otherwise spectroscopy of antimatter would not be possible.

    Fun fact: The current textbook value for the mass of the proton is made up from four measurements and one of these measurements is actually the mass of the antiproton. There are currently groups trying to spectroscopically measure the mass of the antiproton more accurately than the mass of the proton is known.

    Yes, the field is very young (there is only one experiment in the world that can produce slow antiprotons and this one has only been running for ten years) and there is still much to discover. We will see in time whether this is ever going to be feasible.
     
  19. GhostWriter16

    GhostWriter16 Deity

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    Really? How the heck would Venus POSSIBLY be habitable?

    Even Mars, how?

    There are about a thousand problems with Democracy. Let's teach them a Constitutional Republic:mischief:
     
  20. SomethingWitty

    SomethingWitty Prince

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    I think that's the point of his quotation marks. Mars and Venus are within (arguably) the "Goldilocks region" but are obviously uninhabitable.
     

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