Private Mars Rocket II

There is a concept going around in science fiction called "dark forest theory." The popular Three Body Problem trilogy relies on it. New author Patrick Tomlinson's Children of a Dead Earth series relies on it. The theory is this:

1) Given that 90% of stars in our galaxy have planets, which means billions of planetary systems
2) Even pessimistic assumptions about the occurrence and duration of intelligent life, the galaxy should have many such species
3) We haven't seen any aliens
4) Either they are hiding or something is wiping them out.

Item #4 is where we get the name "dark forest theory." The galaxy is like a dark forest, full of predators, and the only way to survive is to hide. The logic of dark forest theory is that any intelligent civilization will eventually advance to a level of tech sufficient to endanger the more intelligent civilizations, so it's best to kill the newcomers before they get too smart. Also driving this idea is that, for a sufficiently-advanced civilization, wiping out a planet is easy. (Take a rock the size of a bus, accelerate it to 90% the speed of light, and crash it into a planet. You will literally turn the crust of the planet inside out.)

Personally, I believe in weak dark forest theory. By this, I mean that their may be predatory alien species out there. I don't believe in strong theory, as expressed in the books above, in which mere indications of intelligent life invites a world-ending strike. I have two issues with the strong version of the theory.

First, practical. We don't make proactive efforts to hunt down ants. We'll kill them if we find them, but we don't hunt them. Nor do we hunt most potential threats. We proactively spend the time and effort to go after proven threats, like mosquitoes. Space is big, hunting down and killing species cost money.

My second objection is the "fastest gun in the West" theory. Simply put, the only civilization that gets an opportunity to do this is the absolute first. If there are multiple civilizations, then the one that starts dark foresting puts a large bullseye on its back. Everybody is gunning for them, out of self-preservation. And the act of being an exterminator means they aren't hiding.

No, the reason we haven't seen advanced alien civilizations is that the galaxy is big, we've only been looking a short time and our current tools could only find civilizations that are changing solar systems.

I was reading somewhere that, in certain Japanese temples, one can see Roman glassware. To be clear, Roman glassware that was purchased when it was new by the temple staff. It was a reminder that the Silk Road was a real thing. So, not only was the road real, but at least some people on both ends of the road were aware of the people on the other end.

Think about that. Roman emperors were at least tangentially aware of Japanese emperors, and vice versa. But from a day-to-day perspective, they had no influence on each other.

Where this ties into space (no, I'm not obsessed about space, I can stop thinking about it any time I want to) is in terms of alien civilizations. The best guess we have about intelligent life in the galaxy is that we would expect, on average, civilizations to be separated by about 200 light years. Now, averages are funny, and so you could have a civilization a thousand light years from its nearest neighbor or one light year and still have an average galaxy-wide of 200 light years.

But 200 light years is a God-awfully long way. Travelling at the speed of light, a trip would take 200 years - assuming you can go that fast and don't need to stop for anything. Even travelling at 100 times the speed of light - or 100 times faster than Einstein says you can - that's a two-year trip one way.

This would, I suspect, set up something similar to the old Silk Road. Sufficiently-advanced civilizations would be aware of each other, and would probably have some low level of trade, but very little real influence on each other.

The universe is big, old and empty too.

Two cool things "borrowed" from jaylake:

Cool Thing #1

I give you The Law of the Tongue, a "treaty" between men and killer whales.

Cool Thing #2

Apparently, as late as 500 million years ago, massive floods were still happening on Mars. It sure looks like there'd be lots of water on Mars today, just buried underground.

Predictions

Jason Kuznicki at The League of Ordinary Gentlemen makes some interesting predictions. I think he's overly-optimistic about some of them (solar and genetic engineering) and right on about others (driverless cars). Two that I want to discuss briefly are the "Great Filter" and a physics paradigm shift.

I've discussed the great filter before, and suffice it to say I don't believe it exists. I do think there are a lot of small filters (we dodged one of them by avoiding a nuclear war with the USSR) but the great filter doesn't exist. The real reason we haven't discovered intelligent life in other planets is simple - space is big and we've only been looking a few decades. I also don't think intelligent life is an inevitable result of evolution nor is it the apex of evolution. There could have been intelligent dinosaurs. In fact, if an intelligent species of dinosaur had existed but been at a Stone-Age level when the rock hit, would we be able to recognize it now?

The physics paradigm shift is more of an observation. Much of modern astrophysics hinges on things like "dark matter" - stuff that we can't detect. As Kuznicki puts it - "the invocation of epicycles is a standard sign that your model is missing something really big." If this is true, then part of why we haven't seen aliens is we're waiting for them to send us a telegraph - a technology they abandoned long ago.

Every once in a while, I get fixated on a really weird concept. For some reason, the current concept was "scale models of the Solar System." Finding myself with a little time, a calculator and an Internet connection, I did a little noodling. I think the results are interesting, and are presented for your amusement.

Start with imagining a Solar System done at the scale of 1 inch = 10,000 miles. This results in an Earth roughly one inch in diameter. Actually, .79 inch, but close enough. Call it a golf ball. Our moon, then, is a .16 inch ball, roughly the size of a pea, 25 inches away. If God were playing golf with whomever He plays with, it would be a gimme putt. It's also the farthest point we've sent humans to.

On that same 1 inch = 10,000 miles scale, the Sun, our local star, is a 7.25 foot diameter ball 775 feet away. Or, in golf terms, a garden shed 258 yards out - a short par 4. Mars (yes, I've got a Mars fixation - sue me) is a ball .4 inches in diameter, and never gets closer to Earth than 508 feet. When its on the other side of the Sun, it's 2,058 feet away. Put another way, in our scale Solar System, Mars is a marble that varies between 169 yards away - a long par 3 - to 686 yards away - out of even Tiger Wood's reach.

So, in our scale model / cosmic golf course, where is Alpha Centauri, our nearest star? At 1 inch = 10,000 miles, the Centauri system is 40,719 miles away! We couldn't fit this scale model on our planet!

If we drop the scale to 1 inch = 100,000 miles, then the sun is an 8 inch beachball, Earth's an oversized dot 80 feet away, and the Centauri system is a pair of beach balls (Centauri is a double-star system) 4,071 miles away. That's just a few more miles than the air miles between New York and Los Angeles.

Space is big and empty. If you want to know the answer to Fermi's Paradox (if there are aliens, why aren't they here?) contemplate this scale model. Space is big, and really empty.

So, via , I find a link to an article suggesting a fatal flaw of Fermi's Paradox. Basically, Fermi's Paradox asks, "if there are other intelligent species in the galaxy, why aren't they here?" An analysis of the paradox suggests that, even with slower than light travel, a civilization could fill the galaxy in about 100 million years.

Except there is a flaw. This assumes that the aliens would have continuous and exponential growth.

When you look at our civilization (all caveats about sample size of 1 apply) the more advanced we get technologically, the less our population grows. A large part of that in our case is, that as technology advances, children transition from useful if unskilled labor to long-term burdens. This pushes birth rates down.

So, maybe the reasons the aliens aren't here is that their population isn't growing.

Yesterday, I was referred to this article on Fermi's Paradox, which hopes that no other life is found in the Solar System, by Tim O'Reilly. For the non-geek, Fermi's Paradox is a question asked by Enrico Fermi, the great physist, "if there are other intelligent lifeforms in the universe, why haven't we seen them?"

The first-cited article spends ten pages talking about the "Great Filter." This is the concept that some event is so improbable of occurrence or difficult to survive that we are the only intelligent species in the galaxy. For example, development of multicellular life may be so unlikely as to almost never occur. Another example may be that many civilizations arise, but they quickly succumb to some massive disaster. O'Reilly's contribution to the discussion is to suggest that Peak Oil is one such event. The idea here is that when we run out of oil, civilization will collapse. Even after or if civilization recovers, they will not be spacefaring because the cheap sources of energy have been used up.

This is by no means a new idea to science fiction fans, as a casual recollection of the literature will find examples of this concept at least back into the 1970s. At least some of those examples suggest inventive ways around the energy crunch. In truth, an energy- or resource-starved world would have even more incentive to go to space. In short, answering Fermi's Paradox with "peak oil" doesn't work for me.

Going back to the first-cited article, part of the problem of Fermi's Paradox is the assumption that we'd be able to observe and detect an alien civilization. This article suggests that detecting random ETA broadcast radio signals from a civilization won't work over even interplanetary distances. Other wild ideas, such as Dyson Spheres, would be difficult to detect at best.

The one "sure-fire" way of finding aliens is to assume that one race built a fleet of self-replicating Von Neumann machines, which would fill the galaxy in a few tens of millions of years. In my mind, this begs two questions.

1) Why build the machines? What benefit accrues to the builders?
2) Could we even detect the machines? There could be a battleship-sized ship or even a fleet of them in say, Saturn's orbit, and we'd not know about it. Nor could this fleet detect Earth's radio signature.

It's impossible to extrapolate from a sample size of one, so the answer to Fermi's Paradox will have to wait.