[h4nkoslo]

Uh oh.

The "great filter" hypothesis is essentially that the rarity of intelligent life has to be explained by some parameter of the Drake equation, and that whatever the "small" parameter is is either in our past or in our future.

If the "great filter" is the rarity of habitable worlds, then clearly we don't need to fear it, since we already found one. But if habitable worlds aren't rare, then it's more likely it lies in our future (e.g. global thermonuclear war, plague, difficulty of space travel, etc).

Thus things like discovery of exoplanets, bacteria on mars, etc should make us rather concerned.

https://en.m.wikipedia.org/wiki/Great_Filter

[root_axis]

The theory as described in your link seems to hand-wave away the difficulties incumbent in the "colonization explosion" step. As it stands, intergalactic space travel (at scale) is utterly inconceivable in practical terms, and to simply assume that it is inevitable seems like a major flaw in the theory.

[idbehold]

> then it's more likely it lies in our future (e.g. global thermonuclear war, plague, difficulty of space travel, etc)

Difficulty of space travel is one of the possible filters.

[root_axis]

Ah. I guess I was responding to

> the only thing that appears likely to keep us from [colonization explosion] is some sort of catastrophe or resource exhaustion leading to the impossibility of making the step due to consumption of the available resources (like for example highly constrained energy resources).

[svachalek]

Actually, the article explicitly calls out that step as one potential "great filter". It also (click the link) lists the theoretical ways it could be accomplished.

It seems to leave out the Von Neumann Probe:

https://en.wikipedia.org/wiki/Self-replicating_spacecraft

This is not exactly colonization but possibly an easier step. Either way, the point is that if either we or our machines can get to another star system and repeat the process from there, exponential growth means it pretty much doesn't even matter how long it takes. In astronomical time, we'd cover the galaxy in the blink of an eye.

[pshposh]

But what if we are the first and no filter exists at all?

[idbehold]

That's almost equally depressing. "Really, we're the best the universe has to offer?"

[logfromblammo]

That's not depressing. It gives us a moral imperative to transplant Earth-origin life onto every somewhat concentrated mass that we can reach.

Then we can wait a few billion years, and the universe will likely have generated a superior successor species which can then re-seed over everything we had previously tilled, and then some.

And they'll all be rubber-forehead aliens to one another, because they'll be billionth cousins, a few million times removed.

[pshposh]

Who is to say we aren't already transplants just looking to reconnect with our cousins?

[SeaDude]

That's what I'm saying!! Panspermia

[sand500]

Think about it, in so many sci Fi, the aliens are pretty similar to us. Carbon based, have DNA, etc.

If we seeded the galaxy with our life then a billion years from now we might get a star wars type reality where many species coexist together all because we seeded every corner of the galaxy.

[idbehold]

> It gives us a moral imperative to transplant Earth-origin life onto every somewhat concentrated mass that we can reach.

And in the very likely scenario that we are never able to "reach" outside our solar system... Then what?

[dragonwriter]

> And in the very likely scenario that we are never able to "reach" outside our solar system... Then what?

Then we need to prepare for the Gliese 710 arrival over the next million and change years. [0]

[0] https://en.m.wikipedia.org/wiki/Gliese_710

[logfromblammo]

Then we will either be literally extinct or at least economically extinct--permanently unable to recover space-launch technology. Then Earth has to gin up another dominant species capable of reaching the stars with whatever time it may have remaining.

We already have the technology to reach outside the solar system. It launched in 1977.

We will have the capability to transplant microorganisms to extrasolar planets long before moving humans that may have 100kg or more to one. Which is good, because it may take a while for the algae to get established anyway. And if for some reason higher species never show up, that celestial object won't have to overcome the steep initial hurdle of abiogenesis.

[ben_w]

I expect the first species that is physically capable of colonising the stars will /only just/ be capable of it.

[pshposh]

This is the best Earth has to offer is how I prefer to think about it. Though I am not even sure humans are the best we have to offer anyways.

[kk_cz]

Isn't that highly unlikely due to the age of the universe vs age of the Solar System?

[joeyspn]

The "Transcension Hypothesis" is a possible solution to the Fermi Paradox...

http://www.sciencedirect.com/science/article/pii/S0094576511...

[ionwake]

Great link, thanks.

Cant help but be reminded of the premise of the Halo games, and the objectives of the alien race.