The Best Way to Find Aliens: Look for Their Solar Power Plants • Hacker News Board

Re: The Best Way to Find Aliens: Look for Their Solar Power Plants

#51

Post by lutusp » Sat, Oct 06, 2012, 2:18 AM UTC

kamaal wrote: post #41

lutusp wrote: post #26

Earlier quoted context omitted.

All true, but applying common sense still has a point. For example, do we want to broadcast the fact of our own existence across interstellar distances? This is actually an active debate topic among those who think about stuff like this. Ironically, after a brief spell of broadcasting our existence with powerful radio and radar waves, we're gradually shutting down the big transmitters for reasons of economy and effic…

>>do we want to broadcast the fact of our own existence across interstellar distances? We are already doing it( http://en.wikipedia.org/wiki/Arecibo_message ). We are also sent a probe with heck lot of details on it( http://en.wikipedia.org/wiki/Voyager_Golden_Record ). >>This is actually an active debate topic among those who think about stuff like this. True, but we have always been sending radio signals in space a…

> We are already doing it ...

Yes, absolutely. It is said that, because of radar, we're the brightest object within several light-years in those wavelengths. Add to that the periodic nature of radar, and we're signaling with an obviously unnatural beacon for anyone willing to listen.

I'm just saying the debate goes on, even though we're providing quite a beacon for anyone interested in detecting signs of semi-intelligent life. :)

> True, but we have always been sending radio signals in space and probably will continue to.

I wouldn't say "always". The first reasonably strong, narrow-band radio signals commenced in the 1920s. Not even 100 years. And we're quickly reducing our EM radiation footprint for economic reasons unrelated to anything resembling policy.

I see the point of both arguments -- that we should, and shouldn't, broadcast our existence. I actually prefer the "should" argument overall, considering the difficulty that an alien species would have getting here. We might learn something remarkable from a safe remove.

Re: The Best Way to Find Aliens: Look for Their Solar Power Plants

#52

Post by lutusp » Sat, Oct 06, 2012, 2:25 AM UTC

grecy wrote: post #49

lutusp wrote: post #28

Earlier quoted context omitted.

Fusion is an energy alternative to coal. Wind is an energy alternative to solar, and vice versa. Things like that.

Right. I get that. Your parent comment implies they would have an "energy alternative" to... energy. When you say " A civilization so advanced as to be able to capture the entire energy of a star, probably also has energy alternatives ". What "energy alternatives" are you talking about?

> Your parent comment implies they would have an "energy alternative" to... energy.

No, not at all. A walking alternative is bicycling, not being a double amputee. A coffee alternative is tea, not dehydration.

"Energy Alternatives":

http://www.energyalternative.com/home.html

Wikipedia: Alternative Energy:

http://en.wikipedia.org/wiki/Alternative_energy

A quote: "Alternative energy is an umbrella term that refers to any source of usable energy intended to replace fuel sources without the undesired consequences of the replaced fuels."

"The energy alternative":

http://www.theenergyalternative.com/

"Alternative Energy News":

http://www.alternative-energy-news.info/

> What "energy alternatives" are you talking about?

Want more links?

Re: The Best Way to Find Aliens: Look for Their Solar Power Plants

#53

Post by goombastic » Sat, Oct 06, 2012, 2:58 AM UTC

It is equally likely an advanced civilization would have found out ways to engineer/create energy unlike how we imagine it. It might even seem irrational to us, magical, impossible even.

Re: The Best Way to Find Aliens: Look for Their Solar Power Plants

#54

Post by sbierwagen » Sat, Oct 06, 2012, 7:38 AM UTC

hcarvalhoalves wrote: post #50

Is it just me, or is there someone else who thinks theories like these are so naive it borders the ridiculous? Isn't it too pretentious to think that, not only other similar civilizations do exist (which is a stretch already), but also predict their infra-structure necessities and what kind of solution they are going to come up with? I known I'm nobody and Mr. Dyson is a Nobel-prize grade genius, but come on... this…

If they want to affect the environment, or perform computations, they have to use energy. If they have to use energy, they have to get energy from somewhere. Hydrocarbons don't last for more than a couple centuries. Heavy-element fission will get you another century. Light-element fusion will get you another ten thousand years.

Whither comes the energy for a million year civilization? Should they ignore their star? Just let all that power go streaming by?

(Dyson won theHeineman Prize, Harvey Prize, Wolf Prize, Templeton Prize, Pomeranchuk Prize, Fermi Award, and the Poincare Prize; but did not win a Nobel.)

Re: The Best Way to Find Aliens: Look for Their Solar Power Plants

#55

Post by grecy » Sat, Oct 06, 2012, 4:00 PM UTC

lutusp wrote: post #52

grecy wrote: post #49

Earlier quoted context omitted.

Right. I get that. Your parent comment implies they would have an "energy alternative" to... energy. When you say " A civilization so advanced as to be able to capture the entire energy of a star, probably also has energy alternatives ". What "energy alternatives" are you talking about?

> Your parent comment implies they would have an "energy alternative" to... energy. No, not at all. A walking alternative is bicycling, not being a double amputee. A coffee alternative is tea, not dehydration. "Energy Alternatives": http://www.energyalternative.com/home.html Wikipedia: Alternative Energy: http://en.wikipedia.org/wiki/Alternative_energy A quote: "Alternative energy is an umbrella term that refers to a…

Interestingly, you're talking about an energy alternative to solar. Do you have an example of one of those?

(My understanding is that solar is the alternative to things like coal)

Re: The Best Way to Find Aliens: Look for Their Solar Power Plants

#56

Post by technolem » Sat, Oct 06, 2012, 5:57 PM UTC

nitrogen wrote: post #43

sbierwagen wrote: post #30

Earlier quoted context omitted.

A swarm-Dyson sphere, which is the only kind that can be realistically built, is incremental. You just keep building habitats in orbit around the sun, until eventually you capture all the sunlight.

Clearly a solid Dyson sphere is not orbiting its host star, and could eventually drift into the star. However, might it be possible to harvest enough energy from the star to power a propulsion system that keeps the sphere in place?

Won't gravity stop this from happening? Seriously, the shell of the sphere will be balanced on the outskirts of a gravity well right? So if it moves this will move the center of the gravity well and both the star and sphere should fall back towards the center.

Re: The Best Way to Find Aliens: Look for Their Solar Power Plants

#57

Post by nitrogen » Sat, Oct 06, 2012, 9:22 PM UTC

technolem wrote: post #56

nitrogen wrote: post #43

Earlier quoted context omitted.

Clearly a solid Dyson sphere is not orbiting its host star, and could eventually drift into the star. However, might it be possible to harvest enough energy from the star to power a propulsion system that keeps the sphere in place?

Won't gravity stop this from happening? Seriously, the shell of the sphere will be balanced on the outskirts of a gravity well right? So if it moves this will move the center of the gravity well and both the star and sphere should fall back towards the center.

According to Newtonian gravity, an object inside a sphere experiences zero net gravity from the sphere, and vice versa.

http://en.wikipedia.org/wiki/Dyson_sphere#Dyson_shell

Re: The Best Way to Find Aliens: Look for Their Solar Power Plants

#58

Post by hcarvalhoalves » Sat, Oct 06, 2012, 10:45 PM UTC

sbierwagen wrote: post #54

hcarvalhoalves wrote: post #50

Is it just me, or is there someone else who thinks theories like these are so naive it borders the ridiculous? Isn't it too pretentious to think that, not only other similar civilizations do exist (which is a stretch already), but also predict their infra-structure necessities and what kind of solution they are going to come up with? I known I'm nobody and Mr. Dyson is a Nobel-prize grade genius, but come on... this…

If they want to affect the environment, or perform computations, they have to use energy. If they have to use energy, they have to get energy from somewhere. Hydrocarbons don't last for more than a couple centuries. Heavy-element fission will get you another century. Light-element fusion will get you another ten thousand years. Whither comes the energy for a million year civilization? Should they ignore their star? J…

Maybe you proved my point. Just look at how many ifs this theory depends upon.

1. That a civilization similar to ours exists 2. That such civilization exists in the same time frame as us 3. That such civilization's demands on energy are similar to ours 4. That such civilization expands enough to face energy shortcomings 5. That the best source of energy such civilization finds is a nearby star 6. That they arrive to the same conclusion as Mr. Dyson about the best way to harness the power from this star (the biggest pretension by far in my opinion) 7. That they manage to build it

A very interesting chain of propositions, but really? I find amusing that are people willing to take this more seriously than a simple imagination/future prediction exercise.

We can't even reliably predict how our own civilization will look like in a matter of decades. Now imagine how naive is to think we can predict which problems hypothetical begins similar to us are going to face, let alone predict a particular the solution they are going to come up with.

Re: The Best Way to Find Aliens: Look for Their Solar Power Plants

#59

Post by dscrd » Sun, Oct 07, 2012, 7:25 AM UTC

w1ntermute wrote: post #16

Solar power? I'm pretty sure they'd be using nuclear fusion.

I'm pretty sure they're just burning plants for energy.

Re: The Best Way to Find Aliens: Look for Their Solar Power Plants

#60

Post by sbierwagen » Sun, Oct 07, 2012, 8:47 AM UTC

hcarvalhoalves wrote: post #58

sbierwagen wrote: post #54

Earlier quoted context omitted.

If they want to affect the environment, or perform computations, they have to use energy. If they have to use energy, they have to get energy from somewhere. Hydrocarbons don't last for more than a couple centuries. Heavy-element fission will get you another century. Light-element fusion will get you another ten thousand years. Whither comes the energy for a million year civilization? Should they ignore their star? J…

Maybe you proved my point. Just look at how many if s this theory depends upon. 1. That a civilization similar to ours exists 2. That such civilization exists in the same time frame as us 3. That such civilization's demands on energy are similar to ours 4. That such civilization expands enough to face energy shortcomings 5. That the best source of energy such civilization finds is a nearby star 6. That they arrive to…

Son, you don't have to start jumping up and down and gibbering excitedly about the singularity. This ain't hard.

All life uses energy. All civilizations will always use energy, because they are made of life forms. (biological or silicon-- who cares)

If civilizations grow steadily, then their need for energy will grow steadily. If they don't flame out, then they'll need to expand beyond their host planet, and intercept more solar energy, until eventually all sunlight is captured, and you've got a Dyson sphere.

If civilizations grow until they hit a threshold, then stay steady-state for the rest of the universe's lifespan, then we'll only be able to detect them if the threshold is pretty big-- if they just stay on their planet, then they'll be hard to spot, without really big space telescopes.