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Eternity in six hours: Intergalactic spreading of intelligent life (2013)

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Re: Eternity in six hours: Intergalactic spreading of intelligent life (2013)

#41

Post by fc417fc802 »

bryanrasmussen wrote: post #33
soraki_soladead wrote: post #10

Earlier quoted context omitted.

We don't know however "It would take so long" is an anthropomorphic assumption of time scale.

of course by the time we had the ability to do von Neumann Probes our anthropomorphic assumption of time scales may have changed. How much would human life span need to increase for a von Neumann Probe to seem reasonable. I would think a life span of 600 and you're thinking, sure I won't get to see it through, but my allotted genetic offspring that I am allowed at age 500 if either of my other two have failed might.

If you expect to live past a few hundred years it isn't clear why your lifespan wouldn't be indefinite. The prerequisites for achieving the former appear to be more or less the same as those of the latter.

Re: Eternity in six hours: Intergalactic spreading of intelligent life (2013)

#42

Post by jmyeet »

ilitirit wrote: post #31

The concept of "Dyson spheres" was a joke by Freeman Dyson. It was never meant to be taken seriously. There's a clip about this floating around somewhere in which he finds it funny that the thing he's most well-known for was not even a serious paper. Dr. Angela Collier did a video about it. https://www.youtube.com/watch?v=fLzEX1TPBFM

The only person who seems to claim that Dyson Spheres were a "joke" is Angela Collier and people quoting her. I've seen no other source for this claim.

But even if it's true, which I don't think it is, it doesn't matter. Why? Because the idea is actually sound and a lot of thought has gone into it by people who have backgrounds in physics and engineering.

It's worth adding that "Dyson Swarm" is the more common nomenclature now because of a mistaken belief that a Dyson sphere was a rigid spherical shell you build around a star. That was never the case and there's no even theorized material that could support this kind of rigid structure. It was always a cloud of small orbitals so the "Dyson Swarm" should alleviate any confusion (hopefully).

Our civilization is ultimately energy-limited. I've seen estimates that we use ~10^11 Watts of energy. The Sun's entire output is ~10^25 Watts. That's a truly staggering amount of energy. We can barely comprehend what might be possible with that much energy. But one of those things is interstellar travel.

Many discussions on interstellar travel gloss over just how large the energy budgets are. But propelling objects with solar sails, particularly if you concentrate energy, seems feasible. At least the physics holds up.

Spreading throughout the galaxy becomes an almost inevitable consequence once you have the capability to do so.

Re: Eternity in six hours: Intergalactic spreading of intelligent life (2013)

#46

Post by hermitcrab »

So a probe travelling between galaxies at 99%c can't hit anything bigger than 1.46×10−12 kg? It is ~2.5 million light-years between us and Andromeda. I don't know how much matter there is between the galaxies (does anyone?). But travelling that sort of distance without hitting anything above that tiny mass seems very unlikely. Also how is your tiny robot probe supposed to power any guidance or maintenance systems for that sort of duration of trip?

Re: Eternity in six hours: Intergalactic spreading of intelligent life (2013)

#47

Post by restalis »

fogof wrote: post #6

I recently saw an interesting criticism of this paper: That by the end stages of the disassembly of Mercury, the amount of heat generated would be so much as to melt the surface, calling into question whether the mass driver system could work at such a high rate.

In the open space, shades get very cold, like a few degrees over absolute zero cold, because even without a medium to facilitate convection and (atmospheric contact) conduction, the loss of heat through mere radiation (into the pitch black universe) is very efficient (for normal, non-reflective materials). Thus, for an astral body to remain in a melted state, continuous steams of energy should be poured in (and some thermo-insulating gaseous atmosphere may also help to reduce cooling, if the body in question would have enough gravity to retain it), but that's hardly a thing to worry for a project where the energy itself is carefully controlled and dosed.

Re: Eternity in six hours: Intergalactic spreading of intelligent life (2013)

#48

Post by krapp »

canjobear wrote: post #21
V__ wrote: post #8

Has someone answered why a civilization would send "von Neumann probes" or similar into space? It would take so long for any answers from those probes to arrive that there really doesn't seem much value in them.

Some will do it, some won’t. The ones that do will be overrepresented in the universe.

An odd assertion to make, given that apparently no one has done it.

Re: Eternity in six hours: Intergalactic spreading of intelligent life (2013)

#49

Post by restalis »

polotics wrote: post #15

Is there already a name for that effect where grandiose plans somehow appear to be more feasible than the simple mundane step-by-step issues resolution that even though they clearly stand in the way of said grand plans, are not worth investing thought and effort in? When it comes to software projects my pet-name for it is the "big-bang theory", but in the article's domain that's kind of already taken.

It's also called "vision". It's what provides and powers directions on large and long term scales. Those "simple" and "mundane step-by-step issues" are just chores by themselves, yet at the same time may become stepping stones in the context of a well thought vision that people buy into and rally behind.

Re: Eternity in six hours: Intergalactic spreading of intelligent life (2013)

#50

Post by hermitcrab »

soraki_soladead wrote: post #10
V__ wrote: post #8

Has someone answered why a civilization would send "von Neumann probes" or similar into space? It would take so long for any answers from those probes to arrive that there really doesn't seem much value in them.

We don't know however "It would take so long" is an anthropomorphic assumption of time scale.

It would take ~5 million years (in the sender's frame of reference) for a probe to make the journey to Andromeda and then send another back with any information. What would the point of that be?
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