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Lonely Planets
Grinspoon, though, never falls victim to the temptation to proclaim that intelligent aliens are a scientific certainty, nor does he ridicule those who come to a belief in aliens by a less-than-scientific route.
The book begins with a historical perspective, telling the old stories of Copernicus, Galileo, Kepler and Lowell in fresh and surprising ways. This makes even these chapters recommended reading for experts as well as newcomers to astronomy. Grinspoon is not content to repeat the usual pieties about these scientific "saints." For instance, he reveals that Galileo did much to intentionally antagonize the pope in his writings about the solar system. He also discusses the more off-the-wall beliefs that many early luminaries of science have held. He explores the link between the end of the earth-centered view of the universe and the beginning of a centuries-long popular craze for the idea of planets around every sun, and intelligent beings on every planet.
The second section of the book deals with the science of suns, planets, moons, and the potential life in, on and around them. All of the popular candidates, including Mars, Europa, and Titan, are discussed in nonscientist-friendly detail. Unearthly life is a broad subject, and Grinspoon does not cover it with perfect evenness. His chapters on cosmology, the early Earth, chemical evolution, and the cambrian explosion are great stuff; but after a quality discussion of DNA, he builds up the idea that RNA most likely evolved first, with ever quite saying what RNA is or explaining its role in our cells today.
But this is a rare omission. The science in the book is sound, and the footnotes and asides consistently entertaining. No song reference or movie quote is left unquoted, always to good effect. Throughout, Grinspoon maintains an almost unheard-of humility, always careful to point out how much we simply don't know about life on Earth, let alone life elsewhere.
The third and final section of the book could never have been written by a less honest or more egotistical scientist. It may also help that he plays in a reggae band. Titled "Belief," part three begins with a discussion of the development and present state of SETI, the Search for Extraterrestrial Intelligence, as nearly anyone with a screensaver knows. Grinspoon explores Fermi's paradox -- if they exist, why haven't they arrived on Earth, or at least said hello by radio? He doesn't duck the hard questions, and he brings us the human story of the SETI pioneers on both sides of the Iron Curtain. He acknowledges that the strong desire to believe in aliens is as something almost religious for many people, including scientists. And he gives the UFOlogists their due, taking a fascinating journey to the San Luis Valley of Colorado. If something really hasn't been adequately explained, he acknowledges that: "there are mysteries. Are we unfaithful to the church of Science if we admit that there are mysteries?" But he does point the finger at a few flimflam artists, and doesn't hide his disappointment with certain alien-visitation true believers who should probably know better.
Maybe the temptation to believe is not so hard to forgive. Where our knowledge is imperfect, our beliefs and hopes always become entwined. Grinspoon ends the book with a meditative chapter on "astrotheology," pulling together the threads of science and faith, exploring the moral implications of intelligent life elsewhere and sharing his own beliefs in the matter.
I recommend this book both for space buffs and for less "scientific," less skeptical readers on their gift lists. The book is worth reading for many reasons -- engaging writing, a friendly introduction to the science involved, eye-opening history, and a chance to learn a skilled planetologist's best guesses at what we may discover living or not living on, in or around Mars, Europa, and yes, Venus. Not since Sagan and Asimov passed away has there been a science writer with such a voice.
Will anyone hate this book? Maybe -- new agers, pot-haters, and supporters of the Bush administration could get their noses out of joint... but only if they read every footnote, and completely fail to take a joke. Most will be as entertained and informed as the rest of us.
You can purchase Lonely Planets from bn.com. Slashdot welcomes readers' book reviews -- to see your own review here, read the book review guidelines, then visit the submission page.
It's incredibly frustrating to me to think that there may be hundreds or even thousands of other species out there that are just too far away from us or technologically displaced from us (we're too primitive or they're too primitive) for us to ever make meaningful contact.
the major advances in civilization are processes which all but wreck the societies in which they occur - A.N. White
According to Michael Crichton, your belief is responsible for global warming.
"The legitimate powers of government extend only to such acts as are injurious to others." Thomas Jefferson.
A recent article on space.com discusses a study that concludes that conditions are ripe for complex life at 10% of stars in our galaxy.
Let's examine your bulldozer/anthill analogy a little closer:
If the fear is that that we might encounter beings who are so far above us that we are beneath notice, this is unlikely to happen, mostly because of the physics of scale.
There is a minimum amount of matter in which one can develop intelligence like our own. We don't know what that amount is, but from observing the world around us we can get a ballpark figure.
It seems unlikely that something as small as an ant could develop human-level intelligence and with it, human-level technology. The scale is too small. Try sustaining an ant-scale fire for an ant-scale blacksmith, for example.
Similarily, there is a maximum end to the scale as well. One might be able to imagine dinosaur-sized intelligences, but it's hard to imagine beings and the associated technical societies that are on the scale of kilometres in size. The loads scale faster than the energy output and material strengths.
So while there's quite a bit of room for variation, it's probably safe to say that for the most likely examples of intelligent, technical societies, objects the size of planets are likely to be signifigant, energy levels involved with intersteller travel are likely to be signifigant, and quite possibly, lifespans are going to be of a similar order (an intelligent, technical creature needs a "timesense" at least as fast as a human's in order to be able to react to physical processes, and I wouldn't be at all suprised to find that the percieved duration of time is closely coupled to the strength of the gravitational field in which one evolved - where stronger gravity equals higher time resolution)
That's not to say that a sufficiantly advanced civilization couldn't wield vastly more powerful energy levels than what we currently manipulate, but scale dictates that dealing with masses on the order of planets or energy levels on the order of stars is ever likely to become TRIVIAL.
Put another way, I don't need a bulldozer to crush an ant - I get that ability by virtue of scale and physics. Those same physics makes it unlikely that anything is going to be of scale large enough to unknowingly crush planets.
Not impossible, but unlikely.
DG
Want to learn about race cars? Read my Book
It seems pretty obvious why ETs wouldn't say hello, at least to me.
:P ). The evidence points to the contrary, yet faith tells him the devil is making the movements in his dog to sway his faith. Jehovah's Witnesses use the same reasoning for the earth only being 6000 years old - the devil created the fossils to sway the faithful (trust me, I had a long discussion about this... mainly because the discussee was very attractive and I had several hours to blow trying to sway her to convert to a life of hedonism).
:)
First off, you have distance. If they said "hello" today, how many thousand or million of years would it take for the signal to reach here? The signal would need to travel the speed of light or less - we don't have tachyon communications yet (if such things exist), so we can't listen to signals that are faster than the speed of light.
Second, in the billions of years the earth has existed, we've been listening for what, thirty, maybe forty years? We don't even know what we're listening for. Who knows - maybe radio became passe for aliens 100 years ago (actually probably more like several thousand because of relativity and distance) and we just missed our chance. Maybe our own radio signals are swamping their faint ones.
Third, maybe they don't care or have a religion that tells them nothing else exists in the universe (like we have several of), so they don't even try. For instance, I know a devout Catholic who believes, as conservative Catholic doctrine preaches, that dogs (technically animals) don't dream, yet his dog is barking and moving while it sleeps - just like a dreaming human would do in REM sleep (well, probably more like talking and moving than barking
Lastly, every planet close to us in the Universe is probably not significantly more technological than we are, so they're probably starting to listen and broadcast themselves and the signals haven't reached us yet. Then again, one good asteroid hit could put alien evolution back millions of years, or one extended prosperous era may have a million years more of a low evolution dinosaur age (ETosaur?). On the average, our tech levels would be about the same (unless we're above or below average, but I have only one society to base observations on, so I my error margin is +-100
Actually, Ward and Brownlee do make estimates as to how many solar systems there are in the known universe based on current projections of galaxies and known (discovered) solar systems. They do not look at particular planets and say that life does not exist on planet A, B, or C. Instead, they discuss all the conditions necessary for the Earth to sustain life and show that repeating Earth's environment (or even something close) is difficult. Earth's evolution for instance proceeded in the way that it did due to millions of factors (climate, planet changing events such as meteors, volcanoes,... etc.)
So, you are right... we cannot say for sure life does not exist on a particular planet without knowing that a planet exists. However, based and what we know about life-sustaining systems (such as Earth) and current percentage of know solar systems, we can estimate the number and probability that planets that meet the correct criteria for life can actually have life, intelligent life, and sustain it.
Anyway, check out my original link to Rare Earth book, pick a used copy somewhere (I believe Alldirect.com and Walmart have the best prices on the book new or used) and check out Ward and Brownlee's arguments for yourself. I am not doing the book any justice with my quick capsule review. Check it out for yourself if you are interested in E.T. arguments and speculation.
(void) signal(SIGALRM, (alarm_fired=1)); if (alarm_fired) printf("Revoke is clueless!\n");
There have been many arguments against the likelihood of life on other planets that have been disproven. For example, we now know with certainty that planets outside of our solar system exist and primitive life can indeed be created spontaneously from environmental conditions present on other planets.
If the conditions are similar, I believe that there would see some of the same convergence of traits that we see with Earth's inhabitants. Yet, how far do we have to look to see the miraculous diversity of life, the amazing phenomenons such as endosymbiosis, and so on? In recent times, many old myths about the unique capabilities of human intelligence have also been disproven. Our definitions of intelligence would really need to be carefully considered in light of life from a different lineage -- indeed, our very definitions of life would probably need to be revisited!
However, I think the pursuit of extraterrestrials tends towards anthropomorphization to the extreme. I don't think people realize how differently technology (culture) and 'science' can be interpreted. Any presumption that aliens would have encountered a similar 'age' of near-nuclear war, development of radios, etc really needs to be checked. We are just looking for ourselves! I also think that the likelihood that we are going to pick up and understand a legible, life-generated radio signal from outside of our solar system is exceedingly remote.
On the other hand, I think exploring the possibility of historical life on mars with Spirit, etc is an excellent measure!
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Fermi's paradox doesn't say much about the time scale of space travel and the evolution of intelligent species. Out of the 13.7 billion year life of the universe, Earth has only been around for 4.6 billion years and only the past few hundred million years have been tremendously interesting in terms of flora and fauna. It seems to me that the chances of an intelligent, spacefaring race visiting our happy little planet in that time window are pretty small.
nuke the moon
How can the natural history of OUR planet be any indicator of what goes on elsewhere? Maybe the magnetic fields in our neck of the woods makes us more aggressive? Maybe the nature of our planet made us cruel? We have evolved enough to where we don't always prey on the weak. For instance going back to the anthill example. We really don't pay much attention to the ants now do we? Not to the point where we feel the need to exploit them. Are they more advanced than us? If not why haven't we dominated them as we should according to your theory?
Although many would also claim that a species more advanced with us may not need or want to subjigate us. Maybe they will have gotten past that need to feel superior. Even in the wild there are examples of more "advanced" creatures living side by side with the less "advanced". Although it depends on your definition of advanced ... weather it merely means stronger. Because at least in wildlife, if stronger means advanced, then only those creatures that need to kill other creatures are really advanced. I'd say ants are pretty advanced, and they live alongside many other creatures.