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Fewer Than 10 ET Civilizations In Our Galaxy?
Al writes "The Fermi Paradox focuses on the existence of advanced civilizations elsewhere in the galaxy. If these civilizations are out there — and many analyses suggest the galaxy should be teeming with life — why haven't we seen them? Carlos Cotta and Álvaro Morales from the University of Malaga in Spain investigate another angle by considering the speed at which a sufficiently advanced civilization could colonize the galaxy. Various analyses suggest that using spacecraft that travel at a tenth of the speed of light, the colonization wavefront could take some 50 million years to sweep the galaxy. Others have calculated that it may be closer to 13 billion years, which may explain ET's absence. Cotta and Morales study how automated probes sent ahead of the colonization could explore the galaxy. If these probes left evidence of a visit that lasts for 100 million years, then there can be no more than about 10 civilizations out there."
All this is assuming that we would know immediately if there were a 50-100 million year old alien probe in our solar system's backyard.
Yes. There could be half a bajillion alien probes in the Kuiper belt, transmitting the latest antics of the Earthlings right to GalaxyTV, and we'd have no idea.
I disagree. I shall propose what will be known as The eldavojohn Paradox which states that: If extraterrestrial life were watching our TV, surely Fox and the WB would have been attacked by now ... or at least a very harshly worded intergalactic message would have been delivered to the Fox executives about their nonsensical canceling of shows like Firefly and Futurama while promoting unadulterated drivel.
... we'll just come back later when you're not busy, ok?"
You see, my assertion that extraterrestrials would enjoy the same television as I is just as utterly inept as assuming that their primary goal is establishing contact with other extraterrestrials. Who knows? Maybe they're too busy jumping between parallel universes to waste time talking to the Corky from Life Goes On of the Milky Way Galaxy? (that being us)
Maybe they showed up and watched World War I and II and said, "Wow, that is some heavy shit. We'll
Isn't the Maybe Game fun? It's like I'm a sci-fi writer with me as my own audience.
My work here is dung.
To add to that:
If you took a completely alien language, encrypted it. Compressed the hell out of it, then applied 10,000 to a million years of technological advancement to the sending of it, would we even be able to notice it from background noise? Even if radio was still used to send it?
1 and 2 are both well known hypotheses. 3 is very unlikely, since we pick up radio emissions from natural sources all the time. 4 is very unlikely, but possible. 5 well known hypothesis 6 interesting! 7 very, very unlikely, given the natural sources we know about 8 what transmission medium does the telepathy use? Is it EM based? Is the range infinite so you don't have to use EM for long distance comm? 9 Yes, it's a bit silly. Radio isn't all that powerful. 10 Yeah, heard that one before once or twice, but not a well-known one. Good job! 11 well known hypothesis : all we can find at this point is beacons, and nobody is using them 12 well known hypothesis : optical works better, but of course is highly directional, and we're not on line of sight
That's one of the major plot threads in Robert Rankin's novel, Armageddon: The Musical. The entire purpose of the Earth is to provide TV entertainment for an alien civilization who has been manipulating humans into doing things to please their viewers and have decided to end the series with a huge apocalypse.
http://twitter.com/OLDTELEGRAM
It is possible that the probes lying at the bottom of the ocean were not designed to get wet because the host planet does not have water at all. Now these probes might be short circuited or something of that kind.
Expanding on this, what if they were looking for a planet like Mars or (harder to detect) Venus? Maybe the probe arived billions of years ago and saw three planets in adjacent orbits with water. Who's to say it would have picked the correct planet?
As for detection, a single object sitting under the dense atmosphere of Venus for 100 million years doesn't exactly pop out at us.
Write your representatives! Repeal the 2nd Law of Thermodynamics!
I know you were joking here, but evolution only seems random from the outside looking in. In any given environment, life will evolve to take advantage of the available natural resources in the most efficient manner possible. Granted, the environment differs greatly from planet to planet, but I think we can agree that any planet hosting life as we know it will have some remarkable similarities to earth. Life will evolve in the best way to take advantage of that environment- two eyes to see in 3D, bipedal for mobility, upper limbs to manipulate things physically, brains to control it all, a mouth at the top and an ass at the bottom because gravity only knows down, some sense of smell to detect fuel(food), ears (or something similar) to detect predators, and some form of genitalia to reproduce. /rant
I often wonder if we are Earth's end-of-the-line inhabitant. Animals evolve to adapt to their environments. Us humans adapt the environment to suit us. Have we stopped evolving? It's a dangerous situation if we have, because then we become a non-changing environment for all the creepy-crawlies we are host to. Bacteria will rule the world in 100 million years!
FOXTROT UNIFORM CHARLIE KILO
No we don't.
We need robots, breeding tanks, freeze-dried embryos. Put a few thousand of 'em (along with DNA samples of a few thousand other humans) on a spaceship, and let the ship take care of the rest.
The goal isn't to offload Earth's population at some linear rate.
The goal is to spawn self-replicating colonies. If the ship travels at 10% of the speed of light (500 years to find a habitable planet within 50 light-years), but the ship can be made cheaply enough (suppose by the year 2200 we can do it for the GDP equivalent of an aircraft carrier and its support fleet), you just fire off a ship in a random direction every 10 years.
The ship finds a suitable world, sets up shop, and the colonists spend the next 1500 years bootstrapping themselves from a Serenity-like Wild West settlements into million-person planetary civilizations capable of building their own seedships. Lather, rinse, repeat.
Some colonies fail. Big deal. Sometimes you'll spread at 0.01c (500 years travel time, 4500 years of playing Sid Meier's Alpha Centauri). Sometimes you'll get lucky - (A ship that lasts for 4500 years and travels 450 light-years - and the lucky colonists reboot after only 1000 turns of gameplay :). Net effect is a wave of colonization spreading out at around 2-3% of c.
The colonies are largely independent of each other; it's unlikely that they're all going to annihilate each other, or simultaneously annihilate themselves. The galaxy's 100,000 light-years wide, or about 300,000 light-years in circumference. The whole thing should be colonized within 10 million years. At less than half a percent of c, we're still talking about a hundred million years.
That's an eyeblink, astronomically speaking. If it was going to have happened, it should already have happened. The universe has been around for 13.6 billion years. Life's been feasible for around 10 billion of those years, after the first wave of hydrogen/helium stars went supernova and gave the universe enough heavy elements to form planets and to do interesting chemistry. Our little rock has been around for around 4.5 billion years, and inhabited for 3.6 billion years of that time. It's hardly a stretch to think that something else started 0.1 billion years ahead of us. (or got started later, but skipped the billion-odd years of time that our biosphere spent dicking around with unicellular life in the precambrian era.)
We're talking about 0.1 billion years to colonize the galaxy. Trivial for an advanced technological civilization. Assuming we're not the first, it should have happened by now. The fact that it hasn't happened is an indication that we're the first. (And as a corollary, that however common life may be in the universe, intelligent life must be mind-bogglingly, astonishingly rare. We've only been sentient for a million years, and smelting metal for a few thousand. An eyeblink of an eyeblink of an eyeblink.)
Your argument is silly. Buses pick you up from bus stops, not from your house. If you want to get on a bus you have to go to a bus stop. An intelligent civilization on a planet a thousand light years from Earth that has astronomers is going to look up and see a similar sky. Even if their eyes only work well in the infrared they can still build detectors (just like we do) that cover the entire EM spectrum. When they build their telescopes they will find the same things we have. Their radio telescopes will pick up synchrotron radiation, pulsars, AGNs, and the CMB. Their optical telescopes will see the same stars and they'll deduce similar if not the same cosmological and physical theories. An important thing they'll find are the hydrogen and hydroxyl lines in the microwave band. These lines are in the middle of a relatively quiet portion of the radio spectrum. These are both radio emission bus stops.
Any alien radio astronomers will be looking at the same frequencies that our radio astronomers do since they're both looking at all the same phenomena. If they decide to announce their presence to the rest of the galaxy their best bet will be to do so on a frequency other radio astronomers are likely to be looking at. You might catch a bus randomly passing by but your best bet is to wait at a bus stop since you can be reasonably sure a bus will eventually stop there. Interstellar messages don't have to be fully understood or translated to be important either. Simply receiving a coherent signal from another intelligent civilization would provide a wealth of information. For one it says "there's someone out there" and that signal is going to come from a specific place. Other types of telescopes can be trained on that location to try to learn all you could about that civilization or at least the environment they live in. The light coming from the planet traveled at the same speed as their radio signal so atmospheric spectra would be contemporaneous with the sending of the signal. Aliens detecting the Arecibo message would be able to look at Earth and see what it was like in 1974 when the message was sent. Knowing there's a civilization there they could keep telescopes trained on Earth to learn more about us even if they didn't fully understand the content of the Arecibo message.
It also does not matter in the slightest if there exist civilizations with esoteric means of communication. If they exist and want to talk to less advanced civilizations they'll communicate via the lowest common denominator of radio or optical transmissions. If they only want to communication via their esoteric means then they obviously only want to talk to equally advanced civilizations and we don't have a lot to offer them (at least they don't think we do). We don't really need to worry about such civilizations, we only need to concern ourselves with the ones stopping at the same bus stop as us. This is also why we tend to look for Earth-like planets when talking about extraterrestrial life. Yes some odd creatures with completely alien chemistries might exist but if we wouldn't recognize them then there is no reason to look for them right now. We can instead look for the creatures with chemistries we do understand fairly well and would recognize instantly. Also in the hunt for Earth-like planets we're not throwing away knowledge of all the non-Earth-like planets. If we find some life form in an asteroid or on the Moon with a chemistry completely unlike ours we can dig through our exoplanet archive and look for markers of such lifeforms on planets we found that were like the home of the life form we found. Just because life forms might exist that are unlike us or civilizations might exist that don't communicate like we do is no reason to assume that all life is unlike ours and all civilizations don't communicate like we do.
I'm a loner Dottie, a Rebel.
Call it the blurker hypothesis. Think about it. The universe is maybe 14b years old. Our own planet is about 4b years old. For Earth to form, there had to be a giant dust cloud full of iron and other heavy elements, which can only have come from novae/supernovae. So at least one generation of stars had to form, burn out, explode, cool to ash, and then reform into new gravity wells to form this solar system. Since this one is about 4b years old, and can be expected to make it another 4b or so, then that leaves a tidy 10b years for a previous star cloud to seed our local region of space. Seems like just enough time. So we haven't seen other intelligent life yet because we are among the first ones to emerge from the ash...