[gambiting]

>>There are no material goods that can justify the material and energetic expense of any interstellar travel.

Material, no. but we know with absolute certainty that Earth will stop being habitable for humans at some point. So assuming any intelligent race, human descendent or otherwise, still exists on this planet, it will have to eventually move. It's just pure luck that we evolved when we did. But there are valid reasons for interstellar travel(other than you know, pure curiosity).

[cyberax]

It's a catch 22. If you want to preserve the Earth's biosphere or even biological humans, then you would need to move at least a ship the size of a small planetoid. That will support life for millenia that will be required for interstellar travel.

And if you can do that, then why bother with the interstellar travel? Just move to a higher orbit to survive the red giant stage. And then move closer to the stellar remnant, white dwarves will provide plenty of energy for trillions of years.

And if you manage to transcribe yourself into some kind of computing-based device, then why bother at all?

[gambiting]

I think moving a small planetoid and moving a planet are not really comparable technical challenges, are they? Even a small moon like Deimos you could probably move by attaching giant rockets to a side and pushing(absolutely absurd, but let's go with it). How would you move the earth with its atmosphere still intact? Is your rocket stretching out the entire way from the surface to the edge of space?

[cyberax]

Arrange a stream of asteroids to transfer momentum from one of the outer planets.

Or just terraform Mars.

[jjk7]

Use the atmosphere itself as propellant gas.

[the_af]

Even if leaving the solar system, or whatever system a sentient race exists, were possible, going to war with another sentience in their home turf (which, remember, must first overcome the near impossible hurdles of getting there to begin with) is so unlikely it makes invasion fears absurd. I think the dark forest theory is groundless paranoia.

Scifi usually bypasses this by breaking the laws of physics, for the sake of storytelling.

[TeMPOraL]

People don't get dark forest at all.

Dark Forest isn't about hiding from invasion. It's about hiding from getting preemptively sniped by someone else, worried that one day you may find a reason and a way to snipe them.

For this to work out you don't need interstellar colonization to be plausible - merely the ability to accelerate a rock to a significant fraction of the speed of light is enough, and that's definitely much closer to science than fiction.

[the_af]

It's still very impractical though. Sniping everywhere that intelligent life might exist is very low probability, low stakes, and for what reason? You don't have any reason to kill anyone you're unlikely to ever meet. And with a weapon which, by the time it arrives, your civilization might be gone. And for what? You cannot compete for resources you cannot reach. War doesn't work like this, it requires anger and an adversary that you can meet in your lifetime.

Dark Forest also assumes aliens aren't curious and thrilled about other life existing out there. The one civilization we are familiar with wouldn't react like this. And we're talking about a very warlike civilization!

[kibwen]

I wouldn't characterize it as "moving". Any excursion outside of the solar system will not be done by anything resembling a modern human, full stop. It may be plausible to send some sort of robot with some sort of nanomachine hoo-hah off in the direction of a nearby star, to seed life there. But no living human will ever leave the heliosphere.