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Robert Bradbury the person who introduced us to Matrioshka Brains has passed away. Here's an eloquent memorium from George Dvorsky. I wonder if we will ever learn that there are billions of Matrioshka Brains in the Milky Way, most of them far from the galactic center. We currently call them dark matter.
If I had my choice of where to live in the Milky Way I would want to be as far as possible from the monster black hole at its center.
Richard Hoover of NASA claims to have found alien microbes inside of a meteorite (right side, left side is a real terrestrial bacterium).
I predict 2 types of responses: pathological rejection and people who equate this with sentient space faring beings.
Frankly I think panspermia is the only theory of evolution which makes much sense. Integrate evolution over 10 billion planets and 10 billion years and you get believable statistics.
One of the reasons life survives on Earth is that we have a big brother protecting us from sterilizing events (asteroid bombardment). Jupiter has been a powerful sink for asteroids that would have killed us all. To find alien life in another system we should focus on those systems which have a large planet well outside the habitable zone as seen here. Exoplanets.org has a list of known exoplanets, and it is sortable by the semi-major axis. Click on that column to sort the exoplanets by their distance from the primary.
Jupiter is about 5 astronomical units (AU) from our G-type star. Here are the first 4 likely candidates.
590 light years away near Pavo is HD 190984 , an F8 star with a big planet at 6 AU.
40 ly away is 55 Cancer, a G8 star with a big one at 5.9 AU.
At 85 ly in Libra, HD 134987 is a G8 star with a planet 0.8 Jupiter masses at 5.8 AU.
49ly away mu-Ara is a G3 star with a planet twice the mass of Jupiter at 5.3 AU.
Statistically speaking these are outstanding targets for hosting alien life. A more detailed analysis may preclude one or more of these due to orbital eccentricity, other planets, or binary star systems. But if spontaneous generation of life is common then at least one of these systems hosts alien life.
Speculation about life on Titan or other cold worlds is misguided because the chemical reaction rates are simply too slow. All chemical reactions have a rate. That rate has an exponential dependence on temperature as described by the Arrhenius equation.
rate = A exp (-Ea/kT)
Ea is the activation energy, k is Boltzmann's constant, T is the temperature, A is the pre-exponential factor
Chemical activation energies are best measured in electron-volts or eV. Typical values are between 1 and 3 eV, usually closer to 2.0. The ground temperature on Titan is around 94 oK or -179 oC.
Thus a chemical reaction on Titan would be roughly 73 orders of magnitude slower than the same reaction on Earth (298 oK). So a reaction which takes a microsecond on Earth would require 10^60 years on Titan. (That's 1000000000000000000000000000000000000000000000000000000000000 years).
Pre-exponential factors for chemical reactions have a certain value which represents steric effects. They cannot be 60 orders of magnitude larger because molecular geometry is not that pliable.
Traditional chemical reaction based life is impossible on Titan or any other location where the temperature is so far below 298 oK.
The SETI Institute will host Celebrating Science 2010 Family Science Faire Saturday May 22, 2010. From their announcement: At our Celebrating Science 2010 Family Science Faire, you will have the opportunity to meet SETI Institute scientists and discover what the future holds for SETI and astrobiology. Learn about the SETI Institute's pioneering exploration of life, our solar system, and beyond, including the search for signals from other civilizations.
Your opportunity for hands-on science! We will have fun, interactive activities for youth aged 8-15. They will be able to sign up on a first-come, first-serve basis for educational science-based activities. We will also have fun and creative activities for our younger up-and-coming scientists.
Meet the father of SETI and author of the Drake Equation, Dr. Frank Drake. Visit the gift shop for a Drake Equation t-shirt and ask Dr. Drake himself to sign it!
Hear Seth Shostak speak at 2:45 on "Why Your Grandkids Will Live in Space." Dr. Shostak will be available to autograph his latest book, Confessions of an Alien Hunter.
Interesting article in Science News about SETI: Can you Hear me Now?
For those who might misinterpret my prior comments on Darwinism here's a clarification. The philosophy of Darwinism leads many people to use the word "paradox" to describe the lack of alien visitors. They all "know" that the evolution of sentient life is easy, so facile, that the Milky Way "must be" teaming with intelligent life. Therefore the lack of alien visitors to Earth is a paradox.
So here's the real science. There is no evidence that any aliens have ever visited our solar system. There is no evidence of artificial constructions in any solar system, star cluster, or interstellar location in the Milky Way. There is no evidence of any artificial construction in any galaxy we can see. There is no SETI signal, there is nothing.
The overall statistics of these observations lead to the following conclusion: the evolution of sentient space faring species is so rare that we might be the only one in the entire universe. The implications for Darwinism are devastating. While the evolution of bacteria might be trivial, and every solar system in the entire universe might contain primitive life, the evolution of intelligent life appears to be nearly impossible.
For over 10 billion years our Milky Way has been easily capable of supporting space faring explorers. Robotic spacecraft could explore the entire galaxy in about 100 million years. If they aren't here yet this means they waited at least 99% of the life of the galaxy before starting. Why did they wait? Statistically it's possible that we are the first, or one of the first, and nobody has been around long enough to explore the entire galaxy: statistically possible, and highly improbable. Either every single species has an impediment to building robotic exploration craft (remember it only takes one) or there aren't any.
For 10 billion years no extra-galactic species has constructed an object visible from Earth. Perhaps such structures are impossible. I doubt it. This is evidence that there are no aliens in other galaxies.
I claim there aren't any aliens anywhere in the entire universe, we are alone, and there is no evidence to the contrary. Many people have speculations, deeply held beliefs about Darwinism, Drake equations, planetary search data, ... but in the end these speculations are irrelevant. Visual observation is all that counts.
So the implications for Darwinism are this, the rate of evolution of intelligent space faring species is about once per universe per 13 billion years. It appears there are millions or billions of planets/galaxy capable of supporting an evolving ecosystem. So for any given planet in the entire universe the chance of evolution of intelligent life is about 100,000,000,000,000,000,000 to 1.
We didn't beat the odds, we just had the winning lottery ticket. If you bought 100 million lottery tickets you would not be surprised to find that one of them had the winning numbers. Out of billions of planets ours held the winning ticket in the Darwinian lottery.
Many recent blog posts continue to try to explain the Fermi Paradox. I'll try to explain why these writers just don't get it. http://enfranchisedmind.com/blog/posts/the-fermi-paradox/
http://www.edge.org/q2006/q06_9.html
http://www.entangledstates.org/2009/06/where-are-they-another-solution-to-fermis-paradox.html
http://www.technologyreview.com/blog/arxiv/23604/
http://arxiv.org/abs/astro-ph/0408521v1
Many people still are confused on several points about the Fermi Paradox. Let's start with the name.
The word paradox is used because everyone "knows" it's a "fact" that there are countless intelligent aliens in our galaxy, despite the fact that none of them have made any obvious contact with humans or visits to Earth. The use of the word "paradox" is sloppy pseudoscience. We don't know, in fact pure empiricism suggests we know the opposite. The complete lack of evidence of aliens in our galaxy is overwhelming evidence that we are alone. The phrase "Fermi Paradox" has become so ingrained that it is almost a single word, and it will be difficult to eliminate it. So I'll keep using it even though I'm convinced there is no paradox.
The reason so many people believe in this "fact" is pure and simple. Darwinism has blinded us to objective science. We all "know" Darwinism is true, and we "know" that it's "easy" for intelligent life to evolve. Therefore we cannot possibly be alone. Let's try to be scientists on this topic. Regardless of your opinion on Darwinism, the obvious evidence is that we are alone.
There is no evidence of intelligent alien life anywhere within or without our galaxy. Look around, and specifically look at other galaxies. We have excellent images of roughly 10,000 galaxies. Not one of them shows an artificial construction. Assuming each galaxy is 10 billion years old, that means that not once in 1e14 galaxy-years has an alien race built a galactic superstructure, visible from our galaxy. Not once. How can any scientist look at this evidence and claim anything other than "humans are alone" ?
And let's be clear, the existence of alien bacteria on a rock orbiting Alpha Centauri has nothing to do with this discussion. I could not care less if every star in this galaxy has primordial life, or even highly evolved tool makers. This is only about intelligent, sentient, technologically advanced space-faring civilizations. Bacteria are irrelevant.
Another point of confusion is the difference between "manned" exploration of the galaxy versus robotic exploration. Frequently bloggers cannot distinguish between these. They say that there are not enough aliens to staff the exploration ships, therefore the exploration of the galaxy will be a lot slower than "commonly" accepted. Again they "know" that aliens would probably not send out self-replicating robots to explore the galaxy.
The fact is that even one self-replicating robotic exploration craft would find every solar system in our galaxy in a matter of 100 million years. That means that for the first few billion years of the existence of the Milky Way no sentient race has built automated exploration craft. Or does it?
A statistical analysis of the evolution of humans from self-replicating RNA demonstrates that evolution is wrong. There are too many permutations available which lead to dead ends. Two billion years on a single planet is not enough time for all the dead ends to be explored. The current theory of Darwinism requires that life "randomly" chose a viable path 99% of the time, instead of a dead end. Most mutations don't work, they result in dead babies, or sterility, or severe biochemical imbalances. Yet evolution on Earth has mysteriously chosen a viable living mutant baby most of the time. What an amazing coincidence !
But what if we combine statistics with the Fermi Paradox? Suppose our galaxy has seen the existence of 1-2 intelligent species that built self-replicating robots. And instead of hardware, the primary substance of those self-replicating robots is biological? Suppose that instead of 2 billion years on one planet, evolution has really had 10 billion years on a million planets. Now the statistics make sense, now we no longer need a miracle of statistics to explain our own biology.
So here's the resolution of the Fermi "Paradox". In the Milky Way (a few million planets over the past few billion years) intelligent life evolved once (or maybe 2-3 times). That species built self-replicating biological explorers which seeded the galaxy. We are the result. Humans are either direct products of alien robotic exploration craft, or we are the first and only intelligent species to evolve in the entire universe.
I prefer the second, I say that the rate of evolution of intelligent life in the Milky Way is about once per 13 billion years. So prove me wrong, with evidence. Real evidence. And don't waste my time talking about what we "know to be true".
Optical SETI offers a much higher chance of finding a real signal because of the simple fact that there are no known natural sources of nanosecond pulses (or shorter). Any 10 nanosecond pulse of light can only be from intelligent life (or of course a shocking new natural phenomenon). Recently a researcher in Australia has detected a pulse. Unfortunately the details of the signal are not available. Thanks to Sentient Developments for pointing out this article.
The details of optical SETI are a lot more complex than radio based SETI. Radio SETI is fairly clear, just listen for a signal which shouldn't be there. But optical SETI requires some understanding of light pulses. For example, every day our own sun puts out flares, which would look like pulses from a few light years away. Supernovae, gamma-ray bursters, novae, and variable stars all put out more light at some point than normal. So what makes an optical pulse natural versus synthetic? The answer is time.
There are no natural phenomena which generate nanosecond light pulses**. A nanosecond pulse means that a burst of photons is detected, and all the photons arrive within a few nanoseconds of each other, then no more arrive until the next burst. In general this means the light was generated with a laser. Lasers are a little easier to understand, all the photons are the same, same color (or wavelength), and same phase. There are continuous lasers which have no pulses, they emit a steady stream of photons.
From a few light years away it is plausible to measure the photon color and determine that a light source is a laser, but unlikely. For example, amateur astronmers know that a planetary nebula emits OIII lines at 501nm. All these photons are the same color but they are absolutely not from a laser. With extremely precise spectrometry it might be possible to determine that a certain set of photons came from a laser. But there would be a lot of arguing.
However, if the laser is pulsed, and the pulse width is less than 100 nanoseconds, then this signal came from a laser built by an intelligent species. It's not even necessary to measure the color of the photons. If they are nanosecond pulses then we are not alone. All that is needed is that the pulse be bright compared with the background. For example, point an 8" telescope at a magnitude 6 star. The telescope collects some number of photons/second, let's say it's a million. So on average about once every microsecond a photon hits the detector. Now suddenly a pulse of 5 photons arrives, all within 10 nanoseconds. Even if that pulse is not repeated it stands out like a beacon, 5 random photons never arrive on top of each other. A 5 photon pulse means we are not alone. This works until the average photon rate is around a 100 million per second, so really bright stars will drown out possible optical signals.
With a photomultiplier tube, boxcar integrator, and a decent oscilliscope we amateur astronomers could build our own optical SETI equipment and discover intelligent life.
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** There is of course always the chance that a shocking new natural phenomenon will be discovered which emits nanosecond pulses. If you discover that you might have to settle for a Nobel instead of aliens.
Fermi's Paradox can be resolved in many ways. My preference is the following: Natural evolution of advanced species is much rarer than most Darwinists would have you believe. It is in fact so rare that the probability of at least one species evolving in any given galaxy is below 1 (perhaps well below 1). Many galaxies never host intelligent life. The number of galaxies which evolve 2 or more is a very small number.
No aliens have contacted us yet because there are no others. We are the first (in the Milky Way). This is not anthropomorphic, rather it is an honest assessement of the probability that random chance will produce intelligence.