Aww, no alien empires yet

[Rynn]

The idea that we shouldn't broadcast just in case is an interesting one. I feel like if there is such a threat out there that we should hide we have no chance anyway. Said threat is likely to be so far ahead of us that hiding for another hundred thousand years won't prepare us.

Then again if interstellar travel is possible and self replicating technology is possible a hostile species could have killed us long before we got to this stage. Which is what Stross is getting at I think.

[Fsci123]

I read an article, I'm not sure where... It said that aliens should be able to detect military radar much farther than TV signals. In fact, with some radar signals, they can determine the size of our planet, our rotation period, and our orbital period. It should look like a dim pulsar like object from afar.

[chris0033547]

Incidentally Charles Stross posted a blog on the topic of the Great Filter coincidentally a few days before this came out. Anders Sandberg has posted in it (and there's a link to a recent blog by him). Stross speculates on some filters (in a half serious manner) and then asks commenters to offer up their own ideas.

My proposal was number 7, copying to here:

So this dials up the speculation a few notches but a possible fGF could be a scientific discovery that provides the same benefits of interstellar travel without requiring it. Important modifier: the edges of this discovery lie along multiple paths that would need to be taken in order to develop interstellar technology.

As an example; a new theory of high energy/exotic physics (useful if you want an interstellar rocket) that makes it possible to construct wormholes. But these wormholes don't travel within our universe but connect to other ones. Third and final point to put the last nail in the coffin for interstellar travel, it's possible to influence these wormholes to connect to a universe with desirable physical laws.

The consequence of this is that before any civilisation gets to the point of sending out rockets they find it much easier to colonise into much more hospitable universes.

Speaking of wormholes: Would it be possible for us to detect an advanced civilisation that uses wormholes?

http://www.wired.com/2010/12/wormhole-detection/

The Known Net probably uses a lot of wormholes and overlaps with the God Web. (And then there are also the wormhole networks of the Panvirtuality and the Diamond Network).

[giulio]

I suspect that advanced civilizations don't engage in mega-engineering because they have much more efficient ways to do whatever it is that they want to do. They have a small footprint because most of them live as pure software and use physical actuators only in case of need (ref. Egan's Diaspora and many other works). They don't build starships because they prefer to travel as radiation beams (like in Egan's Schild's Ladder and Incandescence, and many other works).

Perhaps the phase-transition between pre-tech and supertech is very fast and usually happens in only a few centuries (we are in the phase-transition now). In the 60s we thought that we would have starships and megascale enginenering works in a few centuries, but perhaps we will have much more efficient ways of doing things and nobody will bother with starships and artificial planets. That would explain the Fermi paradox.

[JohnnyYesterday]

It's also possible that Dyson spheres do exist (say built around small red dwarf stars with 10^12+ year lifetimes), just not in huge numbers in those particular galaxies, or our own.

There's a big difference between a Type II and a Type III civilization.

After they've spread enough, and hardened themselves against cosmic existential threats, you've got to wonder what the point is in growing larger and larger across a galaxy. All they would be doing is more of the same.

[chris0033547]

After they've spread enough, and hardened themselves against cosmic existential threats, you've got to wonder what the point is in growing larger and larger across a galaxy. All they would be doing is more of the same.

One idea for continuous expansion might be to prolong their own existence into the distant future. They might turn the rest of the galaxy and eventually even neighboring galaxies into efficient "storage units" for hydrogen. Look at our sun for example. Most of its fuel is wasted, because humanity utilises only a tiny amount of it for its energy needs. And we are only able to utilize it in an indirect way through the generation of electricity from sunlight. That's wasteful. A highly advanced civilisation would be able to use grazers in order to disassemble whole stars and store their hydrogen in a more efficient manner for later usage. They could then access this hydrogen from time to time and create red dwarfs or utilize the hydrogen in other ways and so on. The end result might be something like the Leviathan:

http://www.orionsarm.com/eg-article/4802acd634205

The question is, why all of this galaxy-level engineering didn't already happen and the universe around us is so "wasteful"?

http://en.wikipedia.org/wiki/Blue_supergiant

Because of their extreme masses they have relatively short lifespans

There is of course a possibility that all civilisations eventually create their own basement universes perhaps even with different cosmological constants, which are more suitable for computation and escape from this "inefficient" universe. This way they would also be able to avoid contact with equally advanced alien civilisations, which might be risky for both civilisations and might change their social structures in unpredictable ways. Why share the universe with other intelligent life, if you can create a whole universe just for yourself, where you alone would be the one and only lifeform?

EDIT: The Triangulum Civilisation might have done something like this in order to escape from the Leviathan. Before the Leviathan reached them, they might have been able to create a basement universe and gradually move there. At some point they could "cut the link" (destroy the intra-universal wormhole) and thus escape from the Leviathan.

[Dalex]

Well there is one more disturbing possibility, we are really alone, but not because of Dawn hunters. Because this is a simulation, a virtual world.
Lets assume that you want to simulate our civilization, you don't really need to model things in great detail beyond certain point. Why add galaxy spanning civilizations when you care about one planet and it's development? Its wasteful, unnecessary, it increases complexity beyond what is required. So instead of that just leave rest of the universe blank. Use "normal" physics simulation and be done with it.

[JohnnyYesterday]

Well there is one more disturbing possibility, we are really alone, but not because of Dawn hunters. Because this is a simulation, a virtual world.

If that were true, then we wouldn't be alone. We'd be alone in the simulation, but there would have to be a real world beyond the simulation and the being(s) that started the simulation and maintains the hardware in the real world that it runs on.

Lets assume that you want to simulate our civilization, you don't really need to model things in great detail beyond certain point. Why add galaxy spanning civilizations when you care about one planet and it's development? Its wasteful, unnecessary, it increases complexity beyond what is required. So instead of that just leave rest of the universe blank. Use "normal" physics simulation and be done with it.

If that was the case, why would they even bother to simulate a universe much beyond the planet? They could've stuck us in a Ptolemaic universe, and it would seem perfectly plausible to us.

[JohnnyYesterday]

One idea for continuous expansion might be to prolong their own existence into the distant future. They might turn the rest of the galaxy and eventually even neighboring galaxies into efficient "storage units" for hydrogen. Look at our sun for example. Most of its fuel is wasted . . .

Actually, stars waste very little of their total mass-energy during their lifetimes.

Most of the mass that they started with ends up in the white dwarf or neutron star that they collapse into after the fusion-portion of their lives.

The efficient thing to do would be to leave them alone to burn themselves out, until their mass is needed in deep time.

You can "burn" any matter if you have micro black holes.
If GUT monopoles actually exist, ditto.

[Fsci123]

Well there is one more disturbing possibility, we are really alone, but not because of Dawn hunters. Because this is a simulation, a virtual world.
Lets assume that you want to simulate our civilization, you don't really need to model things in great detail beyond certain point. Why add galaxy spanning civilizations when you care about one planet and it's development? Its wasteful, unnecessary, it increases complexity beyond what is required. So instead of that just leave rest of the universe blank. Use "normal" physics simulation and be done with it.

What purpose would simulating a planet serve?