Reddit mentions of Rare Earth: Why Complex Life is Uncommon in the Universe

Honestly, I don't think life often makes it past the single cell stage. We went for a billion years of single-celled life, and as far as can be determined, complex eukaryotic cells only developed once in all of the billions of years of life here. Just a freakish fluke accident, probably so rare that if it happens more than once, we'll never know because it will be millions of years separated from our time, and probably some other galaxy unimaginably far away. We are alone in a vast, dark, purposeless void.

Interesting book on the topic

The author Nick Lane also gave a nice summary on NPR's Radiolab which is worth a listen.

Also there is the rare Earth hypothesis and more detailed book on the subject.

life everywhere

rare earth

origins of life

a brief introduction

also some taped talks scroll down and click blue "seminar" links.

If FD want to adhere to the science, it seems likely that while microscopic life may be ubitquitous on planets wihin habitable zones, macroscopic life like Earth's may be very rare. Common M-class habitable worlds may be tidally locked storm-worlds, rarer O,B,A and F class stars may leave the main sequence before their Cambrian explosions, and the limited number of terrestrial, tectonically active worlds in non-eccentric, continuously habitable orbits around G and K class stars of the right age (4-5.5 B years for macroscopic life on Earth, til our own runaway greenhouse), and that haven't been sterilized by cometary impact or nearby supernova, may severely limit independent origins for macroscopic life. See Rare Earth, How to Find a Habitable Plant, Lucky Planet, and Where is Everybody for further constraints.

Hence most of the macroscopic life found on HZ worlds in human space may be seeded during terraforming operations. Inhabited Earth-like planets may mostly have Earth creatures, borrowed from the 101 wild animals of Zoo Tycoon, but also the domesticated animals humans bring everywhere they settle.

Truly alien macroscopic plant and wildlife may await till peace accords with Thargoids allow us to land on their own thargaformed worlds.

Ah, but no experts would dare claim that such advanced ET's can be found in our solar system or anyplace that is reachable by humans. As far as other solar systems, I can pretty much guarantee that the only contact we would have would be via radio or laser transmissions. There basically zero chance of a face-to-face meeting. As SETI continues its radio sweeps of the closest stars and finding nothing, the distance for such a contact keeps getting pushed out, way beyond any place that humans can ever get to.

As far as sources, the best is the Rare Earth book.

The Wikipedia Rare Earth page is a good summary of the pros and cons.

It is an interesting argument and I could go either way, but it is becoming increasingly clear that there are no ETs near (say 10 light years) Earth.

If you support the Principle of mediocrity which most people who believe in alien life do. Than you should be thinking that Earth is average, hence why you believe with no evidence that there is alien life. With that logic you can gather a lot of data from Earth and apply that to other worlds. The way we evolved on this planet, how long it took, ect. Even without that thinking, its logical and consistent with what we know if you assume say, if the planet has a light source than the being will have a device to collect it (eyes). Its evolutionarily advantageous to see where prey cannot. Its also a good idea to be able to examine the food your eating. So not only will the being most likely have a mouth to ingest it food, it will probably be near its eyes so it doesn't eat something that will kill it. This is also evolutionarily advantageous. And ect.

Im leaning towards Rare Earth, and there are a LOT of reasons and very logical ones in which why I believe this. Not gunna go on and on, first one that comes to mind is a simple one. Its ourt location, no not within our Solar System but within our Galaxy. Not only do we need to be in a goldilocks zone form our Sun but also within the Milky way. Too close and we probably wouldn't last long with all the bombardment from cosmic rays, gamma rays ect. Too many star systems bunched up and with dangers from super novae, pulsars, quasars ect we would be toast before we evolved. Too high or too low in the Milky Way and we get pelted cosmic rays as well ( I believe). We are travelling at such high velocities as a Galaxy that we are in danger if we leave the protective regions in which we are shielded.

I really suggest before making the assumption that "green men" are out there, you read some discomfiting evidence and specifically on the Rare Earth Hypothesis. Great book is here. There is just so many factors that the average person doesn't realize aside from the one fact you often hear. "So many stars, must mean so many life forms"

Just wanted to add that the Fermi Paradox is very relevant and isnbt to be taken lightly. Truly after 14.6 billion years there4 has been plenty of time to a race to advance and leave its solar system to colonize the Milky Way. Why haven't we seen them or artefacts of them? If I had to concede that there are Aliens than my answer to this question is, we are all stuck in our own solar systems. Space travel inst practical or efficient and faster than light WILL NEVER HAPPEN. So even if you think they are out there, we probably will never see them

http://www.amazon.ca/Rare-Earth-Complex-Uncommon-Universe/dp/0387952896/ref=sr_1_11?ie=UTF8&qid=1347110530&sr=8-11



**By Alien life I mean sentient/intelligent/technology ect. The Rare Earth hypothesis doesn't argue about microbial life.

• If you're just looking for habitability and not civilization then there's probably plenty of that and it needs a place to stay, so see Ray Jayawardhana's "Strange New Worlds: The Search for Alien Planets", which covers planet detection and it is a very interesting survey on recent planet finds, historic firsts, and all the technologies used.
  
  
• If you're looking for support for why we're likely alone see Peter Ward and Donald Brownlee's "Rare Earth: Why Complex Life Is Uncommon in the Universe". Which provides plenty of evidence for why we are likely the only complex life around. The point that stuck with me is the fact that the Earth and moon are essentially a double planet system (rare). And without the moon the earth would be more like mars, in that it would tilt wildly. I forget if the book put forth the following argument, but I think the influence of the moon has kept the earth's core molten and kept Earth's magnetic field strong and let us keep our atmosphere brief discussion here
  
  
• If you're looking for support to say that intelligent life is in many places, see Steven Webb's "If the Universe Is Teeming with Aliens ... WHERE IS EVERYBODY?: Fifty Solutions to the Fermi Paradox and the Problem of Extraterrestrial Life", I didn't find any of the solutions particularly compelling, and I really wanted to. The sci-fi part of me wants to believe that life is everywhere. But it didn't convince me. YMMV.
  
  FWIW: In 2011 I was lucky enough to attend a public lecture with SETI's Seth Shostak's link to reddit comment summary which itself links to a video of the entire lecture
  
  And a few months later SETI's Jill Tarter gave a lecture about extra terrestrial life here's a long reddit comment summary
  
  PS: I think we're all going to kill off civilization farily quickly (possibly global warming, possibly overpopulation there are lots of possibilities) and Sir Fred Hoyle's argument is that once civilization collapses it wil not be able to restart..
  
  > "With coal gone, oil gone, high-grade metallic ores gone, no species however competent can make the long climb from primitive conditions to high-level technology. This is a one-shot affair. If we fail, this planetary system fails so far as intelligence is concerned. The same will be true of other planetary systems. On each of them there will be one chance, and one chance only."
  
  But simple life is probably everywhere.
  
  

Ernst Mayer, Jerry Coyne and Richard Dawkins have written some decent books broadly covering the evidence for evolution. Donald Prothero's Evolution: What the Fossils Say and Why It Matters fits into that general category, and does a good job of outlining the evidence for evolution as well, in particular from a paleontological perspective.




Astrobiologist / Paleontologist Peter Ward has written a ton of fantastic books. I'd start with Rare Earth, which outlines the Rare Earth hypothesis, ie complex life is likely rare in the universe. If you read Rare Earth, you'll come away with a better understanding of the abiotic factors which influence the evolution of life on Earth. If you end up enjoying Rare Earth, I'd highly recommend Ward's other books.




Terra, by paleontologist Michael Novacek describes the evolution of the modern biosphere, in particular from the Cretaceous onwards, and then discusses environmental change on a geological scale to modern environmental challenges facing humanity. It's one of those books which will change the way you think about the modern biosphere, and the evolution in the context ecosystems, as opposed to individual species.




Another book by a paleontologist is When Life Nearly Died: The Greatest Mass Extinction of All Time, looking at the Permian mass extinction, which was the most catastrophic mass extinction of the Phanerozoic wiping out 95%+ of all species. More focused on the geology than the other books I mentioned, so if you're not into geology you probably wont enjoy it so much.



Biochemist Nick Lane has written some great books. Life ascending would be a good one to start off with. Power, Sex, Suicide: Mitochondria and the Meaning of Life is really excellent as well.




The Origins of Life and the Universe is written by molecular biologist Paul Lurquin. It mostly focuses on the origin of life. It's pretty accessible for what it covers.




Another couple of books I would recommend to people looking for something more advanced are: Michael Lynch's Origins of Genome Architecture, which covers similar stuff to much of his research, although takes a much broader perspective. Genes in conflict is a pretty comprehensive treatment of selfish genetic elements. Fascinating read, although probably a bit heavy for most laypeople.

> Neither you nor I can accurately predict the course of technological development over the next century.

What can be predicted is that there will not be technology that violates the laws of physics. Technology that can circumvent it was imagined decades ago, but would require more energy than humans could ever hope to have access to.

> the construction of self sufficient colony ships to last the 100+ year journey between stars is entirely within the realm of known technology and our current understanding of physics.

As I said previously, I am dubious of the wisdom of such an undertaking regardless of the technical feasibility of a colony ship itself. Finding a suitable exoplanet, if one exists, poses a huge challenge with regards to time. Probes traveling at the speed of light would likely take decades, if not centuries, if not millennia to discover another Earth-like planet. It’s also very possible, perhaps even likely, that Earth is unique in the cosmos. In other words, it’s incredibly foolish to fantasize about leaving Earth prior to a suitable replacement being found.

> It is demonstrable that at every point in human history, what we thought was fundamentally impossible has been proved to be possible time and time again. This does not mean all things are possible or that even necessarily interstellar travel is possible. It does mean though, that my claim that it may be possible in the future is not irrational as I have a completely logical basis for my beliefs.

I’m sorry, but no, it is illogical, plain and simple, to believe that something might be possible in the future on the basis that “what we thought was impossible proved to be possible in the past.” It would be like me arguing against colonizing space because “what we thought was possible proved to be impossible in the past.” You know, things like Journey to the Center of the Earth.

> My friend, people from 100 years ago would have viewed our civilization with what we have achieved as veritable gods on earth.

In the past 100 years we have witnessed the useless slaughter of untold millions of innocents through war. As I write this, innocents are being uselessly slaughtered. Most of the world’s population lives in deplorable conditions. We have caused our own biosphere possibly irremediable damage. Tell me, what have we achieved?

> You have no place to say what will become feasible within the next hundred, thousand or hundred thousand years.

Once again, the laws of physics are as they are, and will not change in a hundred thousand years. Therefore I can come to conclusions on the basis of those laws which will hold true for n years into the future.

> I fail to see how you can even begin to possibly say human acomplishment is not astounding. How the hell can possibly be so deluded? We have split that atom, walked on the moon.

Our splitting of the atom has only led to the useless slaughter of hundreds of thousands of innocents, stockpiles of nuclear waste, and a world held hostage by the threat of nuclear armageddon. If these are the consequences of our opening new technological vistas, God help us if we ever do unlock hidden secrets of the cosmos.

> Totalitarian is a system of government. How can an assertion about the nature of discovery be totalitarian?

No the nature of discovery, simply your opinions and style of discourse.

> Humanity is unquestionably the most important thing to have happened in our corners of the universe for quite some time. That fact cannot be denied, and I am not vain for stating it.

It can easily be denied, and has been by any number of prominent philosophers. Therefore, using language like “unquestionably” is why I call you out for being illiberal.

> Hiroshima and Nagasaki were triumphs.

This is a gem on par with your “Earth is pointless” quip.

> We don't have a perfect understanding of the laws of physics, not even in the slightest.

Yes, surely in the slightest. In fact, our lack of understanding is only incomplete in the slightest.

> So many times in the past we have thought they were completely understood and our understanding of them was turned completely on it's head.

No, I don’t think any man of science ever believes anything is completely understood. You keep making this claim, but its unsubstantiated and I’d wager apocryphal.

> It's arrogant to assume that we of all people in history have finally gotten it right,

That’s not what I’m assuming. I’m assuming the laws of physics will hold for the next 14 billion years as they have done for the past equal span of time.

> It's incredible vain on your part to claim that we have such a complete understanding of the laws of physics to rule out the possibilty of interstellar travel

As I’ve repeatedly said, even supposing interstellar travel was feasible, terraforming isn’t. Fantasizing about leaving Earth is foolish.

> But the sun will expand and swallow the earth far sooner than heat death will plunge it into darkness. That's so far into the future though, nobody can even begin to accurately predict where we'll be in even a thousand years, let alone a million or several billion.

Yes we can. The Earth might be uninhabitable in just a few centuries at the current rate of pollution.

> Regardless, if human life can truly be made interplanetary, the sheer rise in the number of human lives who will be able to appreciate the universe we live in, and the wonders they will see alone make the endeavor worth undertaking.

Most of the humans on Earth today live in deplorable conditions. It is silly to fantasize about utopias in space if we can’t even achieve it on Earth.

> You clearly do forget the limitations of your own knowledge, as our understanding of the laws of physics is so incredibly flawed and incomplete, even at our current level of advancement.

No, I don’t. I approach everything I think about through somewhat of a Socratic method. It’s possible to arrive at justifiable conclusions with incomplete knowledge.

> Even so as I said earlier, interstellar travel is entirely possible at sublight speeds within the laws of physics.

But terraforming isn’t.

> Your arrogance is so steadfast that you have somehow fooled yourself into believing that you, and you alone in history understand the limits of possibility.

No, I’m sure there are others who share my opinion and could defend it with far greater voracity and substance than I.

> If you told a man 100 years ago that we'd be flying across the planet in hours on metal birds, destroying entire cities with atomic weaponry, communicating instantly across the world with handheld devices and walking on the moon, you know what he'd call you? Insane.

Not if you told it to Jules Verne.

> I've spent too much time discussing this regardless. See you on mars mate.

You’re right, you have clearly made up your mind and can’t be reasoned with. That’s why in my original comment I made the quip about Earth-leavers scaring me almost as much as religious zealots, since they have quite a bit in common.

Climate's always change, that's a strawman label. But I agree with Craig that man-made global warming extremism is way over-hyped and a big problem. These climatemongers are very dangerous to the human species, far more dangerous than CO2, (which plants use by the way to make Oxygen which we breathe). The truth is the Earth along wth the sun and moon's influence create complex balancing mechanisms for climate. Volcanism comprises most of the CO2 production. We are more in danger of slipping into a runaway iceage. I suggest Calvin and you read this book Rare Earth, chapter 6 titled Snowball Earth and you will get a much clearer picture of what is going on and start to see through the bullshit propaganda.