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Earth Space Science

Is the Earth Special? 745

Hugh Pickens writes "Planetary scientists say there are aspects to our planet and its evolution that are remarkably strange. In the first place there is Earth's strong magnetic field. No one is exactly sure how it works, but it has something to do with the turbulent motion that occurs in the Earth's liquid outer core and without it, we would be bombarded by harmful radiation from the Sun. Next there's plate tectonics. We live on a planet that is constantly recycling its crust, limiting the amount of carbon dioxide escaping into the atmosphere — a natural way of controlling the greenhouse effect. Then there's Jupiter-sized outer planets protecting the Earth from frequent large impacts. But the strangest thing of all is our big Moon. 'As the Earth rotates, it wobbles on its axis like a child's spinning top,' says Professor Monica Grady. 'What the Moon does is dampen down that wobble and that helps to prevent extreme climate fluctuations' — which would be detrimental to life. The moon's tides have also made long swaths of earth's coastline into areas of that are regularly shifted between dry and wet, providing a proving ground for early sea life to test the land for its suitability as a habitat. The 'Rare Earth Hypothesis' is one solution to the Fermi Paradox (PDF) because, if Earth is uniquely special as an abode of life, ETI will necessarily be rare or even non-existent. And in the absence of verifiable alien contact, scientific opinion will forever remain split as to whether the Universe teems with life or we are alone in the inky blackness."
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Is the Earth Special?

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  • by decora ( 1710862 ) on Saturday December 10, 2011 @11:31AM (#38325918) Journal

    "In the air, there is no way for Oxygen to enter our gills. Therefore, water is extraordinary!"

  • Re:Life Adapts (Score:5, Interesting)

    by Anonymous Coward on Saturday December 10, 2011 @11:32AM (#38325948)
    Why do you think that life on other planets would have anything different from us resource and technology-wise? Unless you think the laws of physics and the Periodic Table of Elements are purely local to Earth? What we have now is whatever anyone else anywhere else would have. We won't have FTL spaceships, neither will they. Why is this so hard to understand? There's no Fermi's Paradox, there's only the Space Nutter Paradox: "Given what we know as FACTS, why would you think any other intelligent life would have more capacities than us?"
  • Re:Life Adapts (Score:5, Interesting)

    by ComaVN ( 325750 ) on Saturday December 10, 2011 @11:36AM (#38325992)

    Indeed. A civilisation on a tidally locked planet would probably think life couldn't possibly start on a planet with day and night, or seasons.

  • by Anonymous Coward on Saturday December 10, 2011 @11:36AM (#38326002)

    ...is a civilization of creatures living in a vast ocean of sulphuric acid (or some such), with scientific laboratories we would dismiss as "collections of rubble," that are wondering the same thing about THEIR world...

    We'll never have a common language with them (they're telepaths, you see; think only rocks breaking against each other generate sound waves), and for eternity, we will live in parallel with them, and never interact with each other: Two species, forever locked in their own myopia and confident their science is telling them "We're SPECIAL."

    What an incredible egos must Seven Billion creatures have.

  • 1 in a million (Score:4, Interesting)

    by carpefishus ( 1515573 ) on Saturday December 10, 2011 @11:42AM (#38326072)
    If our solar system is so special that it is one in a million then there are about 200,000 systems that are as special as ours in the Milky Way. Multiply this by 100 billion to one trillion galaxies and we are really not that special.
  • by IndustrialComplex ( 975015 ) on Saturday December 10, 2011 @12:06PM (#38326288)

    How do you know WE aren't the extremophiles?

    Oceans full of a solvent, we breathe a caustic gas... and so on.

  • Re:But... (Score:5, Interesting)

    by postbigbang ( 761081 ) on Saturday December 10, 2011 @12:13PM (#38326366)

    There's more. The "uniquers" are clueless. Is the magnetic field because of our unique liquid core?

    No. We have a lot of iron and rotate. Duh.

    Moons! Look at the moons! Statistically most of the other rocks going around the sun have 'em, too.

    And so forth. Statistically, we're in a zone that allowed the chemicals to make whoopee and produce life, leading to us. People believe they're special, but they evolved something that they narcissitically believe is "intelligence". Do they treat their little planet with care? I don't think so. And they kill each other with glee, and deny the world around them, waiting for magical-thinking to become real.

  • Re:Life Adapts (Score:2, Interesting)

    by Anonymous Coward on Saturday December 10, 2011 @12:16PM (#38326404)
    It doesn't necessarily have to want to contact us, but we should be able to observe these magical spaceships and colonized Dyson Spheres and all the other mythology the Space Nutters believe in.

    The problem is that if you believe that other planets have different laws and different chemical elements, there's no point in astronomy, is there? I mean we look at light from far away and conclude "look, sodium lines in the spectra, bla bla bla", we automatically assume there's sodium and that it behaves like sodium on Earth.

    Thre are no magical forces, no miracle materials, no fantasy energy sources, and certainly no technologies to get close to even the least ambitious sci-fi.

    We still burn fossil fuels in turbines in air or combustion chambers. That's it, that's all. The only thing we've actually made leaps and bounds in is information processing, and that's MATH, it requires very little energy to implement.

    Most of the Space Nutter myths are actually the reverse, they came from the Space Age which somehow assumed we'd have more and more energy but computers would still take up entire basements.

    Reality has moved on, Space Nutters should too. We don't even have supersonic passenger transport right here on Earth where everyone and everything is. Why would you assume that somehow other species don't have the same physical limits?

    It's a nice mythology for geeks, nothing more.

  • by pclminion ( 145572 ) on Saturday December 10, 2011 @12:25PM (#38326482)
    I suspect it's significantly LESS than one per galaxy, so that when life does arise it's almost certainly all alone in its home galaxy.
  • Re:But... (Score:5, Interesting)

    by v1 ( 525388 ) on Saturday December 10, 2011 @12:32PM (#38326558) Homepage Journal

    Didn't the Earth get hit by another planet, causing it to shoot a ton of crust into orbit..creating the moon?

    That's one going theory, but there are good arguments for orbital capture also. The biggest one being the concentration of elements on the moon is different than those found on earth. The moon has a LOT of silicon on it for example, and very little carbon. If it was created by the splash from an impact, one would expect it to have at least a similar concentration of elements as the parent body. Elemental concentration doesn't change a lot over the course of a planet's existence, since elements are formed within stars and planets have to play with the hand they were dealt when they formed. Comets may bring in a little, and atmosphere may bleed away, but the lion's share of the ratio remains unchanged from beginning to end.

    Right now the big hangup on that is we don't know a lot about the interior of the moon, other than it's solid. It's possible the surface of the moon just happened to wind up being mostly Si, and the interior is more of an earth-like distribution of elements. But when planets cool, heavy things go to the core and light things float on top, which is why earth has lots of carbon on the crust and iron in the core. You'd expect the same of the moon.

  • Re:Life Adapts (Score:5, Interesting)

    by rubycodez ( 864176 ) on Saturday December 10, 2011 @12:34PM (#38326584)
    Consider that in less than 500 million years, the earth will be too hot to support life. So that means there is a race, the 5 billion year race from when our solar system began to that extinction time. Maybe most other planets with life lost that race, before anything could overcome the limits of their sun's cooking their home world.
  • Re:Life Adapts (Score:5, Interesting)

    by rubycodez ( 864176 ) on Saturday December 10, 2011 @12:40PM (#38326656)
    ah, it's the AC ignorant of science and engineering again. The only thing we've actually made leaps and bounds in is information processing, and that's MATH No, our fantastic IT is due to tremendous advances in materials science, you should learn how electronic devices such as undersea fiber optic systems and integrated circuits are made. We still burn fossil fuels in turbines in air or combustion chambers. That's it, that's all No, that is not all, where I live we get more than half our power from conversion of matter into energy. And a small company out in the western USA is making astounding advances in polywell fusion

    It's not for visionless people like you to say what is and is not possible. That is for the engineer and scientist to say, people like me. You are consumer, "scrub load" as they say on submarines, users of our gifts.
  • Re:Life Adapts (Score:2, Interesting)

    by Anonymous Coward on Saturday December 10, 2011 @12:57PM (#38326848)

    How do you know this? Earth could be the first successful incubator of intelligent life. There is always a first. Why not Earth?

  • Re:But... (Score:4, Interesting)

    by mcgrew ( 92797 ) * on Saturday December 10, 2011 @01:05PM (#38326952) Homepage Journal

    Well, in the Asimov Foundation universe, the moon made Earth special. It seems to me that you would need something to stir chemicals for life to begin. [slashdot.org]

  • Re:Life Adapts (Score:2, Interesting)

    by Opportunist ( 166417 ) on Saturday December 10, 2011 @01:05PM (#38326962)

    Oh you humans, you always think you're so interesting.

    Why the frck would we waste a buttload of space ship fuel just to fly to your insignificant lump of rock labeled as "mostly harmless" in our travel guides?

  • Re:Life Adapts (Score:5, Interesting)

    by TrevorB ( 57780 ) on Saturday December 10, 2011 @01:31PM (#38327236) Homepage

    Dyson Spheres. Explains all the dark matter. ;)

  • Re:But... (Score:5, Interesting)

    by yog ( 19073 ) * on Saturday December 10, 2011 @01:33PM (#38327258) Homepage Journal

    There are 400 billion stars in our galaxy, and there are probably many billions of planets. Out of all those possibilities, how rare could it be for a planet to be in the "habitable zone" of a star, with a few gas giants farther out? And isn't iron a fairly common element in planets, hence molten core, hence magnetic field protecting the surface from cosmic rays and all that.

    If we suppose that Earth-like conditions are one in a billion, which seems exceedingly conservative, nonetheless we're talking about dozens or hundreds of Earth-like planets out there. It's reasonable to suppose that our conditions are not that uncommon, and there might be an order of magnitude more Earth-like planets.

    There also would be millions of planets that are much harsher than Earth, yet perhaps some form of life could have evolved.

    A counter argument might be that even our world was not always friendly to life; during Earth's first billion years it was quite a harsh place indeed. Subsequently there were several mass extinction events, the last one a mere 60 million years ago. During pre-Cambrian times, it's believed the planet was basically a giant snowball. Alien probes sent here during those periods might have concluded that there was no sustainable life.

    I think it will be a good 200 years before we can get out to some of our neighboring stars and investigate up close. Even the closest stars would take multiple lifetimes to get to using any current or upcoming propulsion technologies. Ultimately it will be some kind of intelligent robotic explorer that we send out as a kind of trans-generational emissary, that may come back to entertain our distant descendants with tales of foreign worlds. Sad that trans-light propulsion is nothing but a pipe dream, for now anyway.

  • Re:Life Adapts (Score:5, Interesting)

    by melikamp ( 631205 ) on Saturday December 10, 2011 @01:42PM (#38327380) Homepage Journal

    They should have had plenty of time to fill the galaxy by now.

    This is a big unfounded assumption. And while jump-starting life and moving bacteria around may turn out to be easy, moving animals the size of humans to a star system even 20 ly away is already known to be very, very hard. (I mean, mammals could not reach New Zealand for millions of years, and that's another continent, not another star.) And while colonizing deep space is a priority, persisting without a big chunk of rock in the immediate neighborhood is probably a pipe dream. So we should probably think of it as a planet-sized organism (like Earth with its biosphere) casting a seed (a generation ship) to a different star system. One needs to find a planet that's already ripe; being optimistic, there is one within a few dozen ly. One needs to build a big ass ship in deep space, capable of withstanding a several (or many) thousand year journey with a self-sustaining biosphere inside, so probably something like an asteroid several hundred meters in diameter. Then one has to accelerate the sucker with something at least as good as fusion and slowly crawl towards the goal. Just the travel itself is easily 100000 years, and building an ark is a tremendous job as well. Once arrived, colonists cannot hope to propagate again for hundreds of thousands or may be millions of years, since they don't have a planet backing them, so there is more downtime.

    Think about what I like calling a "hop time": the mean duration needed for a generation ship to colonize a planet, build a new generation ship, and travel to the next system. It's gotta be pretty big, may be a million years, may be 10. So if someone has a billion years on us, they may be on their 100-1000th hop. They are but a smidgen, may be as big as the width of the galactic disk. And if they are on the other side of the galaxy, we may not run into them for another few billion years.

  • Re:Life Adapts (Score:5, Interesting)

    by Dogtanian ( 588974 ) on Saturday December 10, 2011 @01:45PM (#38327408) Homepage

    Your mistake is in assuming that the starter gun fired at the same time for everyone. That isn't true, we're late to the game. Other planets finished forming and starting up their life engines more than a billion years before ours did. The question is, where are those folks? They should have had plenty of time to fill the galaxy by now.

    Thing is that mankind only arrived on the planet *very* recently in evolutionary terms. In addition to this, we've made incredibly fast levels of progress in the past few thousand years, and the past hundred years has seen technological change orders of magnitude faster than *that*.

    It's fair to assume that this process hasn't stopped yet- the logical conclusion some have drawn is the "singularity". Well, whether or not that happens, the bottom line is that we're in the middle of a change that's happening incredibly suddenly- the blink of an eye, the flash of a camera bulb- compared to the relative "hours" or "weeks" that life has existed on the planet overall.

    Now, there *may* be a significant number of other worlds that are presently capable of supporting life out there, i.e. at the same time as ours. But even if there are (e.g.) hundreds of them, even if they *broadly* follow the same trajectory and timescale as earth (in terms of the evolution of life), even if their development was congruent to ours in the larger scale of things, the chance of even one other world's "camera flash" evolutionary moment occurring at exactly the same time as ours is incredibly small.

    This matters because if they're even slightly behind, they're probably still at the monkey-level intelligence stage (if we're lucky), or the stage earth was at tens or hundreds of millions of years ago.

    If they're even "slightly" ahead- e.g. a million years on the evolutionary scale of things is pretty "close" to us- then they're probably so far ahead of us that we won't even be able to begin to comprehend where they've gone, assuming their development (even if it eventually slowed down) went through the rapid phase that mankind is going through- and continued, even if only for a few thousand years!

    This does assume that mankind's current rate of development can be continued at least for the immediate future. Still, I'm surprised that I haven't seen the above issue even considered elsewhere. Maybe I overlooked something obvious?

  • Re:Life Adapts (Score:5, Interesting)

    by Surt ( 22457 ) on Saturday December 10, 2011 @02:08PM (#38327698) Homepage Journal

    No, your theory has definitely been considered by many. Technological singularity changing the priorities of the civilization and/or rendering it invisible is definitely a possible explanation for the missing gating factor. That escape from the universe might be possible with a technology only slightly ahead of our own would explain everything (because this universe with its stupid second law of thermodynamics is a dead end that any reasonably advanced civilization would WANT to leave).

  • Re:But... (Score:5, Interesting)

    by Will.Woodhull ( 1038600 ) <wwoodhull@gmail.com> on Saturday December 10, 2011 @02:38PM (#38328012) Homepage Journal

    Pardon in advance for any meanderings. Several interruptions while composing this.

    And yet the Moon might well be the cause of several other factors.

    The Moon is massive enough in comparison to the Earth that it is reasonable to consider the two to be a binary planet system in many ways. While the barycenter of the binary revolves around the Sun in a highly predictable ellipse, the Earth itself does not; it meanders inside and outside that elliptical orbit due to the Moon's influence. As a consequence, the location of the Earth's perihelion can shift more than one degree from one year to the next (varies from Jan 2 to Jan 4). The barycenter of the binary system is displaced from the center of the Earth toward the Moon by 75% of the Earth's radius (quick reference here [astronomycafe.net]), which from the point of view of a flat Earth theorist means that the barycenter is rushing along 1,000 miles beneath our feet at about twice the speed of sound.

    And of course there are the tides.

    Not just the ocean tides, but also the much greater tidal bulge of the atmosphere. And a definite tendency to a tidal bulge in the liquid core. IANAGeologist so I don't have a clue how the tidal forces and the weight of the mantle would interact... but then I think that most geologists have never considered this either since they are always looking down into the Earth and the Moon is for them a whoosh in the finest Slashdot meaning.

    As far as evolution of life goes wrt planet Earth, the Moon is at the very least a major, significant stirring rod. It is really hard to say how major, since we are in the position of being stirred so everything else that is also being stirred with us looks very normal. It could be that both meteorology and geology need their Copernican revolution and won't really make sense until they meet their Galileos.

  • Re:But... (Score:2, Interesting)

    by Tsingi ( 870990 ) <{moc.liamg} {ta} {kcir.maharg}> on Saturday December 10, 2011 @03:18PM (#38328466)

    Maybe, but it's pretty obvious that the GP to your post is anti-Christian.

    Just like reality. Ok, reality isn't anti-christian, it's just that christian beliefs are disproved by reality.

    Not anti-Christian, anti-religion. It is generally "morally" upheld that people have a right to their beliefs. I see not harm in this, as long as their "beliefs" do no harm. It wouldn't be difficult to propose a set of beliefs that most would immediately reject, but this does not seem to be the case with religion. For some reason it gets a free pass. People uphold the good things in religion as an argument that excuses the bad things. They do not. That religion espouses some good things does not excuse all the harm that it has done and continues to be done in the name of a superior being.

  • Re:But... (Score:2, Interesting)

    by Opportunist ( 166417 ) on Saturday December 10, 2011 @03:24PM (#38328532)

    Says the guy who doesn't need the evil eye from a bearded guy on his fluffy cloud to be a good person.

    Capitalist society is exactly what makes a deity necessary. We're still savages, bashing each other's head in for the juicy goo inside. Just that now it's more subtle and less bloody, we just ruin each other financially instead of outright killing each other. Else, same shit as 10,000 years ago. And that's exactly what God was created for, to keep us from doing exactly that and to give us a way to live alongside each other.

    The system is out of check because nobody gives a crap about God anymore, but neither have we actually really evolved past that caveman stage of bashing each other's head in. So either we return to the God-fearing state of earlier, or we finally get our act together and start evolving. Past our caveman genes and into a more humane society.

    But for that, we first of all would probably have to eliminate the general laziness, and the general love for having someone else do the work for us.

  • by ShieldW0lf ( 601553 ) on Saturday December 10, 2011 @03:40PM (#38328686) Journal

    How about "Prevent Seasonal Affective Disorder Induced Suicide By Putting Up Lots Of Lights And Reminders That Things Will Get Better In The Spring While Getting Drunk And Exchanging GIfts Day"

    It served a much more important and practical purpose before pervasive electric lighting came along. It kept you alive.

  • Re:But... (Score:2, Interesting)

    by Professr3 ( 670356 ) on Saturday December 10, 2011 @06:02PM (#38329938)

    How often does someone have to just sit there and accept being kicked in the face before responding is acceptable?

    I believe you're making my point for me, to some extent. Your beliefs (or professed lack thereof) should not require the extermination of everyone else's.

    Sure, militantly fundamentalist posts turn up at -1 in searches (so do plenty of militantly atheist posts). I came right out and said that my evidence is anecdotal, after all :P I don't see how any of it belongs on Slashdot in the first place.

    To address your point about the "special earth" topic being religious in nature, I have to disagree. It's statistically improbable that our world is unique (or nearly so) in its hospitality to the emergence of life, but that doesn't mean it's a religious argument. The question is whether or not the Earth is on the far end of the statistical curve among the galaxy's population of planets, not "intelligent design" vs. "random chance".

"Let every man teach his son, teach his daughter, that labor is honorable." -- Robert G. Ingersoll