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Grabby Aliens (2021)

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Re: Grabby Aliens (2021)

#171

Post by antifa »

makeworld wrote: post #163
bonzaidrinkingb wrote: post #129

This theory is itself grabby, and grabs itself at that. > Furthermore, we should believe that loud aliens exist, as that’s our most robust explanation for why humans have appeared so early in the history of the universe. But if loud aliens will soon fill the universe, and prevent new advanced life from appearing, that early deadline explains human earliness. Even furthermore, we should believe that Big Foot Medusas e…

> humans are the terraforming organisms put in service of the grabbies to make our planet habitable Now there's a thought.

It is interesting, but I think a civilization capable of planning on million year timescales would have a better plan.

Re: Grabby Aliens (2021)

#172

Post by zare_st »

mattashii wrote: post #133
zare_st wrote: post #128

Earlier quoted context omitted.

A hypothetical megastructure Dyson's sphere would not radiate heat. And I'm not so sure that you can apply the stealth principle here. Stealth inhibits active measurement and astronomical measurements are passive. We have sensor resolution and we have a mass of data to sift through - each time sensor generation or data processing advances, we see stuff we haven't seen before. The data is analyzed as a dynamic system.…

> A hypothetical megastructure Dyson's sphere would not radiate heat Could you elaborate why not? All current technology I know of has an efficiency of <100%, with waste energy being lost as heat (which in space would be radiated away in the infrared spectrum). Why would this not be the case for a hypothetical dyson sphere or swarm?

Because the topic isn't about heat per se but heat signatures and detecting artificial heat signatures across the universe.

Of course everything radiates heat I did not think I have to get down to that level in commenting here.

Re: Grabby Aliens (2021)

#173

Post by zare_st »

cwillu wrote: post #139
zare_st wrote: post #128

Earlier quoted context omitted.

A hypothetical megastructure Dyson's sphere would not radiate heat. And I'm not so sure that you can apply the stealth principle here. Stealth inhibits active measurement and astronomical measurements are passive. We have sensor resolution and we have a mass of data to sift through - each time sensor generation or data processing advances, we see stuff we haven't seen before. The data is analyzed as a dynamic system.…

A Dyson's sphere is a device to convert high frequency photons (visible light and uv) to low frequency photons (radiated “heat”). A sufficiently deep stack of shells can bring the temperature of the radiated light closer to the temperature of the cosmic background radiation, but it absolutely will radiate.

Which is exactly my point.

The question isn't whether Dyson speheres radiate, the question is can we detect an artificial megastructure and my answer is no, based on the hypothetical Dyson design.

Re: Grabby Aliens (2021)

#174

Post by yreg »

zare_st wrote: post #172
mattashii wrote: post #133

Earlier quoted context omitted.

> A hypothetical megastructure Dyson's sphere would not radiate heat Could you elaborate why not? All current technology I know of has an efficiency of <100%, with waste energy being lost as heat (which in space would be radiated away in the infrared spectrum). Why would this not be the case for a hypothetical dyson sphere or swarm?

Because the topic isn't about heat per se but heat signatures and detecting artificial heat signatures across the universe. Of course everything radiates heat I did not think I have to get down to that level in commenting here.

Sorry, I don't understand you either. Without new physics Dyson spheres radiate heat. Therefore they are detectable.

Re: Grabby Aliens (2021)

#175

Post by throwuwu »

whizzter wrote: post #166
throwuwu wrote: post #144

Earlier quoted context omitted.

You might want to check the physics on your assertion that a starship could take out a city. It’d have to be designed to do so otherwise it would just vaporize as it entered the atmosphere at the velocity you’d need for that kind of impact.

I haven't done any calculations (since we don't have any feasible crafts for interstellar travel that's irrelevant really), but considering it for a few minutes I'd say there's 3 increasingly likely ways around that. 1: Considering the amount of rocket fuel we need to leave earths atmosphere and reach the Moon, people have been proposing nuclear rockets to reach Mars. That's still within the solar system, reaching an…

If we’re talking specifically about interstellar craft with enough shielding to survive an uncontrolled reentry at high velocity then what the heck are those going to be doing near a planet? Sublight travel would have to be performed by craft large enough to support the crew for years if not decades or generations. You’re not going to want to maneuver that much mass into orbit around a planet. They’d be better off parked in a trojan orbit and letting smaller craft move people and supplies back and forth You might as well try to hijack an aircraft carrier and fat chance of surprising anyone if you could pull it off.

To get a ship to hit the ground at the velocity you’re talking about a large chunk of it would need to be solid steel like a bullet basically. Space craft aren’t built like that, they need to be mostly empty space for storing propellant and people. A reactor and its shielding might survive but that’s on the scale of 5 - 10 meters and it’s still not 100% solid so it doesn’t compare to a large metallic asteroid.

Throwing rocks at a planet might work but you need the right equipment and expertise to bullseye a planet from 100 million miles away and if anyone saw you do it they could take their time intercepting the rock.

Re: Grabby Aliens (2021)

#176

Post by yreg »

qnleigh wrote: post #167
yreg wrote: post #118

Earlier quoted context omitted.

How can a particular technology have a non-competitive harmonious society as a hard requirement for it's discovery?

If the resources required to communicate are planet-scale, then it would require comparable cooperation to build it. Maybe that gets you somewhere. And then maybe you choose to communicate in a way that requires massive resources at the receiver end too... Not a full answer to your question, but this gets you somewhere. A more compelling answer to me is this; civilizations that don't learn how to cooperate at the sca…

Planet scale cooperation utilizing planet scale resources is possible in a planet scale military dictatorship as well. Actually it sounds easier and more plausible than in a free society.

> A more compelling answer to me

Agreed, but that's just the usual great filter idea.

Re: Grabby Aliens (2021)

#177

Post by jiggawatts »

throwuwu wrote: post #142
XorNot wrote: post #73

Earlier quoted context omitted.

That itself would be quite interesting though, because based on what we know now it's merely difficult, not impossible with reasonably foreseeable technological improvements. The dynamics which would make it impossible on any known timespan don't seem currently observable.

If you assume FTL travel will never be developed then distance and time are simple limiting factors. How do you keep a cohesive civilization going when communication takes 200 years? Or even just 20? Here on Earth entirely new languages and cultures arose across distances that wouldn’t even cross a state line when communication was limited to a small handful of travellers and merchants. Any colony further away than 5…

Consider a colony of bacteria multiplying by splitting. Each new pair of cells is independent and do not cooperate. Some die, some stay put. Nonetheless, the “colony” spreads and explores new territory with zero coordination of these activities. Certainly not an intelligent centralised leadership!

Even if our first interstellar colonies diverge immediately and some even turn into reclusive hermits, some may expand, repeating the cycle.

Re: Grabby Aliens (2021)

#178

Post by yreg »

Towaway69 wrote: post #123
yreg wrote: post #118

Earlier quoted context omitted.

How can a particular technology have a non-competitive harmonious society as a hard requirement for it's discovery?

Think of technology that we can't imagine. Just as we can't imagine a harmonious society, so we can't imagine the technology that would arise from such a society. It's a recursive argument, I know, but that's the core of the problem.

I'm sorry, but this seems like handwaving. I don't see why we couldn't imagine the technology?

Perhaps we are using technology in different context. I mean understanding of physics + a machine (made out of matter) built thanks to that understanding. Do you perhaps mean something else?

Re: Grabby Aliens (2021)

#179

Post by beAbU »

iraqmtpizza wrote: post #145
LadyCailin wrote: post #103

Earlier quoted context omitted.

That’s like looking only in the drawer, and saying, there is no evidence here that a cat lives in this house. When in fact the cat is just upstairs.

There are electromagnetic waves reaching the earth from this galaxy which were emitted anywhere from 80,000 years ago to an instant ago, and everywhen in between. Practically all alien races among the hundreds of billions of solar systems would have to have been electromagnetically silent for a minimum of 80 thousand years for us not to see them. If you include other galaxies, then they would've had to have been sile…

You might enjoy this creepypasta of yore...

https://creepypasta.fandom.com/wiki/Radio_Silence

Re: Grabby Aliens (2021)

#180

Post by yreg »

shrimp_emoji wrote: post #150
yreg wrote: post #115

Earlier quoted context omitted.

Even if interstellar travel is impractical, an advanced expansionist civ would be interested in building megastructures. And since there is no stealth in space (unless you can somehow mask heat), they should be observable. Ofc there are explanations for that part of the paradox as well, but the impractical travel theory doesn't cover it.

You're implying we'd easily see megastructures. Believe it or not, there's many more stars we haven't inspected than have. And our telescopes suck too much to see all but the largest megastructures, which you're assuming it would make rational sense to build in the first place. There can be better things for an economy to spend its (always finite) resources on.

> which you're assuming it would make rational sense to build

Yes I mean why not. If you are an expansionist advanced civ, travel is impractical and you have enought time and resources then what else is there to do?

Obviously there are explanations "why not" (as I said), but insterstellar travel unavailability is not one of them.

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