Milky Way has 'billions of Earths'

Discussion in 'Et Cetera, Et Cetera' started by eddyabs, Feb 15, 2009.

  1. eddyabs

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    It just seems like news fodder...and it's something that most of us have probably always believed, but now science is beginning to confirm that indeed this fact is most probably true. It's a truly relevatory and astounding premise, that if indeed is true will be looked upon by future generations as another milestone in humankind's history.

    Billions of Earths....BBC.
     
  2. Deno

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    Not for a minute, just because there are a billion stars that may have planets don't mean one of them has the exact parameters that's required for life to exist, and thats not news either. In a billion planets that might be around stars maybe only a few hundred have liquid water, and maybe only a few of those have water that is drinkable, and then only a few of those that don't have extreme gravity issues before we even get to the atmosphere issues. There is only one Earth, there might be other planets that are inhabitable but will we ever find the means to get there before natural disasters destroy what life there is here.

    The closest star is alpha centauri and its 4.7 light years away, which means if we could travel the speed of light it would take 4.7 years to get there and whats the chance of a planet being there at all yet one we could inhabit.
     
    #2 Deno, Feb 15, 2009
    Last edited: Feb 15, 2009
  3. HazelGod

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    Your basis for this declaration is...?
     
  4. eddyabs

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    Personally I go the other way....there are estimated to be roughly 100 billion stars in the Milky Way alone....and it's pretty much confirmed by scientific observation that all stars are at the heart of a system of planets. If you remember not long ago it was believed that Mars was a dead planet. Only last year the spacecraft Phoenix discovered ice (frozen H20) beneath the permafrost.

    Water discovered on Mars.

    .And that's a planet within our own solar system. I'm a believer....our galaxy is vast....

    Edit....'Billions of Earths' is in quotation marks...meaning Earth-like planets.

     
    #4 eddyabs, Feb 15, 2009
    Last edited: Feb 15, 2009
  5. Deno

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    Earth is what we call our planet, other planets would be called something else.
     
  6. eddyabs

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    As above...Don't you think we and they (the scientists) know this!!! They mean Earth-like planets!! *slaps head*....although who knows...in a parallel universe, perhaps even our own, there is an Earth clone....if the Universe is infinite, then there are infinite possibilities....
     
  7. Deno

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    Why they didn't say earth like planets is beyond me, that's journalism for ya. I still say it does us no good regardless. The emphasis on vast being the reason.
     
  8. eddyabs

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    It also means that when we look at Alpha Centauri, we are looking at it as it was 4.7 years ago.....one of the furthest visible stars is Eta Carinae, which at 7500 light years means that we are seeing it as it was 7500 years ago...the star could go supernova today and we wouldn't know about it (with the visible eye) for 7500 years!
     
  9. wispandex_bulge

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    Actually you need to do a little more research here. Very few stars have observable planets, and even fewer are yet observed. Further more, single stars appear to be the exception to the rule rather than the rule, meaning there are more multiple star systems than single star systems. When you have a multiple star system the chance for planet to have a stable orbit is greatly decreased, and beyond that, a planet with a stable orbit is very unlikely to be close enough to the stars, themselves, to be warm enough for life as we know it.
     
  10. Big Al

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    Scientists used to believe that life was only possible within a narrow range of conditions. Recent discoveries of life in extremely hostile environments however have made a lot of them reconsider the parameters.

    Also consider that there may be alien biologies not dependent on water. They may thrive on methane or some other hydrocarbon. Sulfur-based life may be a possibility, as well as other variations that we have no frame of reference for (radiation, exotic energy, etc.)

    The universe is a huge and very strange place, and while what we know about it is increasing by the year we still have only a tiny grasp of knowledge about it.
     
  11. schwulboy1989

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    They're not saying it's definite...they're saying it's very likely...and the requirements for life could change depending on the life forms. we can't know. all we know is the earth we have here (and I use the word "know" lightly when it comes to our own planet....we've still got a ton of stuff left to discover)

    besides, it's not just liquid water that makes earth unique. it's having water in all three stages at the same time. I think it's safe to give the scientists a chance. And as far as never getting there, there have been so many breakthroughs in science that people never dreamed of...who's to say we can't do this, too?

    As others have said, they weren't trying to imply that it was a gazillion other planets called earth. although why would it matter if they were? i'm up for more than one "Earth"...and technically, our planet is called Terre, not "Earth"; our sun Sol, and our moon Luna. You learn new things every day :)

    And as far as journalism goes, their job is to make it short sweet and simple. I don't think they were trying to mislead people, so much as just get the story out. I'm sure most people probably understood what they meant.

    i say we give them a chance :)
     
    #11 schwulboy1989, Feb 15, 2009
    Last edited: Feb 15, 2009
  12. eddyabs

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    Yes I agree that pretty much the only type of planets observed so far are other gas giants, due to their immense size, and only when that planet passes in our view, across the face of the observed star....but planet spotting is really in it's infancy right now, and who knows how this particular science will evolve....but thanks for the heads up, I learnt something new there.
    Nonetheless, there are still billions of single star systems, so I for one would find it improbable that there is only one 'Earth-Like' planet.
     
  13. Deno

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    Well when most of your theoretical astrophysicists say speed of light travel is impossible ya gotta sorta believe them. That certainly don't make it so.
     
  14. eddyabs

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    Yes, discovering light speed would be akin to discovering the holy grail....but this is not about travelling to 'Earth-Like' planets, rather, the discovery of the likelihood of.
     
  15. jason_els

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    I think, with all respect, you're underestimating the size of the known universe. It's many, many, times bigger than you think it is; exponentially so. This is true even for astronomers. No matter how big we can apprehend, we just can't apprehend the true size of the known universe. It's a mental limitation we have as humans.

    The key is that we know that earth has happened at least once so we can't say it's impossible so much as improbable. Alpha Centauri is actually a triple star system with two of the stars getting as close to each other as Saturn is from the sun. This would make Alpha Centauri unlikely to be able to support an earth-like world as that world would be pretty much cooked by both of its suns. Naturally astronomers are very interested in finding planets in this system, but so far none have been found. Even if we did find one, however, Alpha Centauri is still about 43 trillion miles away despite the fact it's our closest neighbor.

    Earth is very lucky. We're in the galactic exurbs. We don't have many neighbors and the ones we do have are quite distant. This is good because it helps protect us from galactic dangers like novas and gamma ray bursts.

    The class of star we have in the sun is pretty common. The sun is a very ordinary star going through a very normal life cycle. That's a good thing for us as well because some stars have very violent lives that would make life on any planets difficult. Most stars though, do have one or more companion stars and they orbit each other (like Alpha Centauri A and Alpha Centauri B and their more distant sister, Proxima Centauri). Multiple suns can make life formation very difficult as it would be very easy to have massive temperature changes on any planet revolving around any one of the stars. Not all binary stars have irregular orbits around each other, however. Many have very stable orbits with enough distance between the two to allow a stable Earth-like planet to form.

    But that's not always the case. There are likely about 10 billion lone sun-like stars just in this galaxy, just as isolated from the hustle and bustle of the galactic center as we are. And there are likely about 500 billion galaxies in the universe. Now if we simply average that figure of 10 billion times 500 billion, we get 5.0 x10²¹ possible stars that are just like our sun. We also know now that planets aren't all that rare. Current estimates are that out of all stars, 5% have planets but in metal rich stars (like our ordinary, common sun), that figure rises to 20%. That's just an estimate extrapolated from current extrasolar planet findings. As we detect more extrasolar planets, that figure will rise. Finding extra-solar gas giant planets (like Neptune, Saturn or Jupiter) is relatively easy compared to finding comparatively small rocky planets like our own Earth, Mars, or Venus. In any event, finding planets isn't all that easy no matter what kind you're looking for, at least for right now.

    Once again, our biggest hurdle is distance; at least in our current ability to detect dimensions. Right now we imagine space travel based upon the four dimensions of time, height, width, and depth. We currently think we have to travel within those dimensions to reach these stars. What's most intriguing is that we may not have to. If the 11 dimension theory pans out, then we're only able to perceive 4 of the 11 dimensions we inhabit and that means we may come to detect a means to travel via at least one of those dimensions to where ever we want without having to worry about time and distance. We may be able to use gravitational lenses to enter another dimension and travel that way, or we may find some other means to do so.

    Don't forget that human evolution has been rather late in the history of the Earth. Earth has had life for about 4.5 of its 5 billion years as a planet and has had at least two devastating extinctions where life essentially had to reboot nearly back to square one. What if other Earth like planets didn't suffer these misfortunes and life was allowed to evolve uninterrupted? Imagine humans being not just 200,000 years old but 3-4 billion years old. We can't imagine where we will be in 3-4 billion years or even what we'll look like but what technology might we have? Contemporary humans would appear to be no more advanced than chimps using branches to catch ants though already we have some technology which may be able to prevent the past disasters that caused the mass extinctions of Earth's past. 200,000 years to be able to deflect a possible asteroid isn't all that long. If other civilizations could advance to our point, and even if they were beset with the same problems of religion and competition, it's safe to wager that they would have developed similar technologies to prevent further mass extinctions. That would given them a truly uninterrupted period of techonological and evolutionary development literally spanning billions of years.

    We may be alone, however this article states what most astronomers and exobiologists now believe; that we are now statistically certain that we are not alone even though it does not guarantee intelligent life. It does at least guarantee that there are extrasolar inhabitable planets out there for us to colonize and exploit or, if inhabited by intelligent life, contact.
     
  16. eddyabs

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    Wow, Jason, I'm impressed at your insight, and at your ability to explain in simple terms matters that others would struggle to interpret in that way, including myself....excellent post.
     
  17. D_Jared Padalicki

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    Simple: some things we will never know, but man what is it interesting to know what else is there in our universe!
     
  18. JustAsking

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    Jason,
    What a beautiful piece of science journalism. You have a real talent for bringing science to the non-scientist.
     
  19. dong20

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    Actually, neither of those statements is correct. It is part of the closest star system to us, which is close, but not the same and a common misconception.

    Estimates of habitable planets in our own galaxy very widely. But with assumptions about habitability being [effectively] based on a single example it's hard to draw definitive conclusions. To me, it's inconceivable that Earth is the only habitable planet, or even the only Earth-like planet.

    As for there being up to 100 billion (per the linked article), with an 'estimated' stellar population of 'only' 200-400 billion in the Milky Way, I'd have say that seems unlikely but then 'up to 100 Billion' also allows for just one.

    One the other hand, if the theory of parallel/alternate universes is in fact correct, they may indeed be billions of Earths. :biggrin1:
     
  20. jason_els

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    Thanks guys but I have an ace in my pocket. I was taught how to do this by three dear friends who did (or do) this for a living: Fred Hess, Joe Rao, and Isaac Asimov.

    If there's any fairness in heaven, I'd love to spend many more nights with Fred and Isaac.
     
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