von Neumann probes, Dyson spheres, exploratory engineering and the Fermi paradox

von Neumann probes and Dyson spheres: what exploratory engineering can tell us about the Fermi paradox

Talk by Stuart Armstrong, at the Oxford physics department

Abstract: The Fermi paradox is the contrast between the high estimate of the likelihood of extraterritorial civilizations, and the lack of visible evidence of them. But what sort of evidence should we expect to see? This is what exploratory engineering can tell us, giving us estimates of what kind of cosmic structures are plausibly constructable by advanced civilizations, and what traces they would leave. Based on our current knowledge, it seems that it would be easy for such a civilization to rapidly occupy vast swathes of the universe in a visible fashion. There are game-theoretic reasons to suppose that they would do so. This leads to a worsening of the Fermi paradox, reducing the likelihood of "advanced but unseen" civilizations, even in other galaxies.

• Category

  Science & Technology

[Dan Beeston]

This was great. I found it really enjoyable.

My goodness. Science nerds sure do like cutting in don't they?

[FHIOxford]

Speaker: Stuart Armstrong, currently working at the FHI

[TrueLazyGamer]

I like the scale of this. 'Grab the universe' sounds like an epic idea!

[deathmetal11111]

I would not hold it against the presenter if he went over to the guy at the bottom right of the screen and punched him. He put together a very good presentation. At least let him finish and save your questions to the end and not butt in every five seconds.

[houseklh]

I much enjoyed this talk. It's an excellent analysis of the paradox. I can think of two explanations why we haven't seen visitors from other galaxies: (1) attainment of technological life soon leads to total loss of interest in "blasting the universe"; (2) cannot transport a Von Neumann through space at relativistic speeds without it getting destroyed by high speed particles and radiation. signed, keiths interweb

[CASTRA76]

ummmmmmmmmmmmmmmm

[MeltedCheesefondue]

You'd orbit the sun. The mining/lifting modules would stay down on the surface of Mercury until it disintegrated too much.

[Admiralhall2000]

as for us being aliens that's rubbish.

[Admiralhall2000]

Maybe the reason why this has not happened is that aliens either don't exist or that they are too far away! (Outside the observable universe or in a bubble universe). 

[Johanan Raatz]

Hmm, I was thinking in the sense that spin-foam could be part of what Fredkin calls "Other." What space-time originally emerged from.

[SerielThriller]

i enjoyed this video, but it seems next to impossible to pull off

[adamskubel]

Spin networks are just a way to quantify interactions between particles and fields. Which means "existing within the spin foam" is not possible without also existing as observable matter.

So while it stands to reason an advanced race would live within a simulation, they are still constrained by the quantum limit (Planck volume). Thus, in order for them to expand they would still need space+matter+energy, the collection of which would almost certainly result in us observing them.