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In search of ET: Fear of what’s out there causes split among space scientists

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Re: In search of ET: Fear of what’s out there causes split among space scientists

#21

Post by svachalek »

blueadept111 wrote: post #11
SOMA_BOFH wrote: post #6

I haven't seen any anti-METI argument which counters this: "Humans, Vakoch said, have been using radar, which can purportedly be detected 70 light-years away, since World War II. Television and radio signals would long ago have signaled our presence to malevolent space ruffians, he said."

Counter argument: So if we've been using radar since WWII, and radar has been capable of signalling our presence to alien civilizations, then we don't need METI. Alternatively, if METI is proposing a signal that can reach alien civilizations in a way that TV and radio signals cannot, then the original objections to METI still stand, and the TV/radio signal argument is a red herring. But really, it's just common sense…

This, exactly. What METI is proposing, as I understand, is a stronger, more unmistakable signal of intelligence which carries higher risks.

Also, this is 70 years of noise, a blip on the galactic timescale, getting weaker the farther it goes. We can't stop what's gone out already but that doesn't make us obligated to keep advertising our presence forever.

Re: In search of ET: Fear of what’s out there causes split among space scientists

#22

Post by jandrese »

This is not something I'm worried about. Unless FTL travel is real, the amount of resources necessary to make the trip to kill off/enslave humans makes the entire effort unprofitable. Basically, if you have the ability to travel between star systems, you already have the technology to exist effectively forever in a self contained environment. You can mine asteroids/planets forever in your own solar system for effectively unlimited materials.

Its like you are thirsty so you build an intercontinental jet plane from scratch using parts from around your house to fly to Japan to steal a single Coke from a 7-11.

Re: In search of ET: Fear of what’s out there causes split among space scientists

#23

Post by maze-le »

SOMA_BOFH wrote: post #6

I haven't seen any anti-METI argument which counters this: "Humans, Vakoch said, have been using radar, which can purportedly be detected 70 light-years away, since World War II. Television and radio signals would long ago have signaled our presence to malevolent space ruffians, he said."

Here is one:

Absent any form of antenna technology we don't know about, all of these signals are going to be extremely dispersed and very near to the rate of noise, for any receiver that is even moderately far away. It is still possible to detect these signals, but only you know exactly what you are looking for. Not only the direction and frequency of the signal are needed to know, also amplitude, polarization and any form of modulation pattern. Otherwise, the signal might just be interpreted as noise.

Also 70 ly are "not even beyond our backyard" so to speak. 70 ly is such a small distance, compared to other possible distances in our galaxy. It is a far too small patch to be taken as a basis and extrapolate to the rest of the 27000 ly of galaxy ahead of the signal. Maybe the space ruffians are 80 ly away from us, or 800...

Re: In search of ET: Fear of what’s out there causes split among space scientists

#24

Post by jandrese »

headcanon wrote: post #12
SOMA_BOFH wrote: post #6

I haven't seen any anti-METI argument which counters this: "Humans, Vakoch said, have been using radar, which can purportedly be detected 70 light-years away, since World War II. Television and radio signals would long ago have signaled our presence to malevolent space ruffians, he said."

A counter to that might be that these signals aren't strong enough to accurately detect our exact location at interstellar distances. Parallax is hard at those distances - if we were to get a signal from a point in the sky, whats to say its coming from one star, or another one "behind" it? Not possible to determine from the signal strength alone, since you don't know the signal's original strength. In Carl Sagan's Co…

It might be hard for us to figure out where the signal is coming from, but an alien race that is capable of traveling between star systems shouldn't have any problem figuring it out. Frankly if such an alien race exists they already know there is life on Earth just from the changes in chemical composition of our atmosphere. They can even figure out when we discovered agriculture. In a few decades they will even know that we discovered radio communication.

Re: In search of ET: Fear of what’s out there causes split among space scientists

#25

Post by bovermyer »

bryanrasmussen wrote: post #3
bovermyer wrote: post #2

I will never understand people who are afraid of the unknown.

I will never understand anyone who would randomly pick a mushroom from the forest floor and start nibbling on it.

Eating mushrooms in the wild is not even remotely similar to inviting contact from other sentient species.

Re: In search of ET: Fear of what’s out there causes split among space scientists

#26

Post by CharlesColeman »

jandrese wrote: post #22

This is not something I'm worried about. Unless FTL travel is real, the amount of resources necessary to make the trip to kill off/enslave humans makes the entire effort unprofitable. Basically, if you have the ability to travel between star systems, you already have the technology to exist effectively forever in a self contained environment. You can mine asteroids/planets forever in your own solar system for effecti…

That's assuming aliens prioritize profit. Perhaps they're technologically advanced and have everything they need, but have deeply internalized the logic of using preemptive strikes to protect themselves from potential future threats.

Such a strike might not even be that expensive or need FTL technology: just send out a few one-way nuclear-armed suicide drones at 0.12 c [1], via a path that obscures their origin (e.g. via a gravitational slingshot or three).

[1] Perhaps with a design like https://en.wikipedia.org/wiki/Project_Daedalus, https://www.damninteresting.com/the-daedalus-starship/, which is probably even within our technical capabilities. We also have weapon designs that could render the a planet uninhabitable (e.g. https://en.wikipedia.org/wiki/Salted_bomb).

Re: In search of ET: Fear of what’s out there causes split among space scientists

#27

Post by jandrese »

NickM wrote: post #18
rvcdbn wrote: post #15

What possible resource does Earth or human civilization possess that ETs advanced enough to pose an interstellar threat would be interested in?

I sort of agree, but to be fair a nice habitable planet could be a really rare and valuable resource in and of itself, assuming there are any life forms out there with biology similar enough to our own to find Earth desirable.

Also assumes there aren't a bunch of Earth-like worlds that are otherwise uninhabited that would be much easier to colonize than one with potentially hostile/poisonous natives.

Re: In search of ET: Fear of what’s out there causes split among space scientists

#28

Post by mc32 »

jandrese wrote: post #22

This is not something I'm worried about. Unless FTL travel is real, the amount of resources necessary to make the trip to kill off/enslave humans makes the entire effort unprofitable. Basically, if you have the ability to travel between star systems, you already have the technology to exist effectively forever in a self contained environment. You can mine asteroids/planets forever in your own solar system for effecti…

But you’re thinking of it as intentional and directed attack. It can simply be collateral damage. “Oh, what’s there, let’s send a one way selfdestroying probe (don’t take this literally).

But you can imagine a situation where like we’re looking for life on Mars and in doing so inadvertently destroy unknown life.

Re: In search of ET: Fear of what’s out there causes split among space scientists

#29

Post by SOMA_BOFH »

blueadept111 wrote: post #11
SOMA_BOFH wrote: post #6

I haven't seen any anti-METI argument which counters this: "Humans, Vakoch said, have been using radar, which can purportedly be detected 70 light-years away, since World War II. Television and radio signals would long ago have signaled our presence to malevolent space ruffians, he said."

Counter argument: So if we've been using radar since WWII, and radar has been capable of signalling our presence to alien civilizations, then we don't need METI. Alternatively, if METI is proposing a signal that can reach alien civilizations in a way that TV and radio signals cannot, then the original objections to METI still stand, and the TV/radio signal argument is a red herring. But really, it's just common sense…

Is there a proposal from METI more capable of reaching out than this 32MW transmitter with a 1.4° beamwidth which has been operating continuously for decades?

https://en.wikipedia.org/wiki/Eglin_AFB_Site_C-6#How_the_rad...

Re: In search of ET: Fear of what’s out there causes split among space scientists

#30

Post by zzzcpan »

coleifer wrote: post #7

Not discussed by the article, but I wonder...Is it more terrible to find out that nobody's out there? Nobody's listening?

Or how about this: find out that somebody's out there, but not evolved enough to be listening? This I find likely. Fixes Fermi paradox too, since this doesn't assume high probability of random life on some planet evolving as far as we did in those billions of years.
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