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

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).

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.

This is the wrong way to look at it. You're not thirsty for resources. You're protective of them. Imagine if you were aware of giant, angry Americans who were flying to Japan to steal all of your coke and convert all your land and resources into coke manufacturing plants.

Do you let the plane in? Do you stop it from traveling at all? Do you glass the surface of America with nuclear weapons? How do you know they won't do it to you?

Even mere humans, who've only reaped the fruits of serious scientific advancement for a few hundred years have already come up with a way to get to Alpha Centauri within 44 years.[1]

All such spacecraft would have to do to cause massive devastation is aim at Earth and not stop, though it's likely that more advanced civilizations could come up with more effective means of destruction.

Alien civilizations could have advanced scientifically for thousands, hundreds of thousands, or even millions of years. It is unlikely that we can accurately put limits on their capabilities.

[1] - https://en.wikipedia.org/wiki/Project_Orion_%28nuclear_propu...

"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."

The flaw in this analogy is that the you with these capabilities has different, and possibly incomprehensible desires, compared to the you who wants a Coke.

The natives of Central America and Mexico were not aware of how excited those Spaniards would be about Gold and Silver.

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. Everything we know about the universe tells us that complex organisms exist at the expense of simpler organisms. As a nascent space-faring civilization, we are the minnows in the ocean, and signalling our presence to the bigger fish is the kind of mistake that a minnow only makes once. What exactly is the perceived positive outcome of making contact with a more advanced civilization?

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 Contact, we were only able to determine the signal came from the star Vega because it was the only star that would have been at the right distance to receive our earliest radio signal and transmit it back to us - also Vega is relatively close by compared to other stars, close enough that our parallax created by our orbit around Sol was sufficient to get a read on signal source.

A deliberate attempt at active signaling would remove all doubt for an extrasolar observer.

Liu Cixin's The Dark Forest explores this scenario in depth. I would explain more but don't want to reveal some important spoilers.

> 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."

I think the key word there is "purportedly." Has anyone done an analysis about what kind of equipment would be required to detect those old signals at 70 light years? Has there been any analysis of how for out they could propagate until they were totally overwhelmed by noise?

Personally, I'm skeptical that those signals were transmitted powerfully enough or focused narrowly enough to likely be detected. This article (https://www.nature.com/articles/461316a) makes it sound that way:

> Indeed, SETI is marked by a hope, bordering on faith, that not only are there civilizations broadcasting out there, but that they are somehow intent on beaming their signals at Earth. An alien SETI project relying on a similar faith in Earth would be sorely disappointed. It's true that a random mix of radar and television signals has been expanding outwards from Earth at the speed of light for the past 70 years. But there have been only a few short-lived attempts to target radio messages at other stars — with each attempt arousing concerns over alien reprisals.

The atmosphere point is even more compelling. Earth has been broadcasting with quite non-trivial power "I HAVE LIFE" for about two and a half billion years. Most of the "hostile alien" hypothesis work out to the hostile aliens needing to exterminate all life, not just life that already seems to be intelligent, because you don't know how fast something might become intelligent when you're not looking, so if Earth was going to be wiped out, it should have been a very, very long time ago.

https://en.wikipedia.org/wiki/Great_Oxygenation_Event

(Since someone will probably bring it up, no, I do not believe extinction events are aliens trying to wipe out life, on the grounds that if intelligent, hostile aliens intended to wipe out life on Earth, I'd expect them to succeed, and not merely inconvenience life briefly, but actually totally and permanently sterilize Earth. Any culture that can fling either mass or energy at early Earth in any reasonable period of time is already very near the necessary energies to do that. Across billions of years I'd expect someone to have managed.)

Another reason why I tend towards the "yeah, we are non-trivially alone" myself. Maybe the entire universe isn't empty, but I don't think there's any reason to believe there's anything nearby.

At best, that says “any badness within 70 LY has already been tipped off.”

The METI guys are working on more powerful emitters specifically so as to send additional data that will be coherent over larger distances.

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...

Really? How many habitable exoplanets are within 70 light years, and what are the odds of life (let alone super-advanced space pirates) existing on them? Also a little known fact: only energy travels at light speed. So even in the worst case scenario, they won't be here for a few hundred years.

The motivation isn't exploiting Earth resources, but killing us before we can kill them. Most humans don't believe non-human species have any right to life, so why would sapient aliens believe humans have any right to life? Humans have a non-zero probability of growing powerful enough to be an existential threat to the aliens, so the safest option is to preemptively eliminate them.

And even if the aliens are convinced that humans are 100% alien-friendly, it would still make sense to kill us all because there's a chance we'll develop uncontrolled recursively self-improving AI ("intelligence explosion"), which would be a threat to the aliens without us intending it.

You can't know or understand possible ET motivations or capabilities.

Humans routinely drive other species on Earth to extinction, our own cousins. We also damage our own planet's environment.

It may be logical for an ET to just destroy us the way you might destroy a harmful bacteria, which might otherwise spread unpredictably. It wouldn't be about wanting slaves or raw resources (although as someone said, Earth itself might be considered somewhat valuable).

If you saw a sharp change in the atmospheric composition of a planet in our solar system would you think "volcanoes" or "life"?

The Three Body Problem and ASI are two songs on the same instrument: value misalignment in cases of massive power differentials.

In an indifferent universe, two optimizers optimizing different things will be in conflict. Can we build machines that optimize what we want to optimize? Can we align our optimization with aliens before it becomes optimal for one of us to annihilate the other?

I don't think we're alone. But I do think we're kind of trapped in our Solar System along with everybody else. Interstellar travel is so outrageously expensive that by the time you have the technology to do it you necessarily have the technology that makes it unnecessary.

An interstellar journey means you need a ship that can survive indefinitely in deep space, where you don't get free energy from solar panels or have easy access to comets to mine for materials. An in-system habitat has to be a solved problem before you can even consider building one. But at that point you have effectively unlimited living space, energy, and materials so why bother?

Even if your sun is turning into a red giant you can move your habitats to the optimal distance to sustain life. It's really hard to imagine a time when Humans have used up the entire mass of the other planets in the solar system and need to look outward for resources. You could build an almost unimaginable number of O'Neill cylinders using only the mass of Jupiter.

Bondage, you say? Sounds like Rocky Horror Picture show.

The point is not some specific fate, but that anything could happen. And anything includes loads of bad outcomes , most of which we are probably unable to imagine.

I didn't downvote you, but this seems extraordinarily unlikely to me. Why would our extraterrestrial overlords want to use us as slaves? They travelled a long way to get here, surely they should have robots or a genetically engineered underclass or something. We're in the process of making human labor obsolete ourselves. The only scenario I can imagine where this makes sense is one where the aliens have interstellar travel but lack decent genetic engineering, and they're interested in exploring/building/mining in places that are inhospitable to both their own biology and robotics but not our biology (like a planet whose gravity would crush them that also has an EM field that would fry circuits without exceptional shielding). This seems like a stretch to me. I feel like wiping out a potential future threat is a much more reasonable incentive, with exploitation/study of an already existent biosphere being a runner up. Most of the things they could want humans for would be more efficiently accomplished by phytoplankton and krill. You're right that nigh-perpetual enslavement is the most horrifying possibility, it just seems implausible.

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.

We might be tasty.

Earth is a rich, temperate, naturally life-sustaining planet with a strong protective magnetic field. Regardless of what form of life an alien species would be, that may be of interest in and of itself based on mere rarity. Why bother terraforming if you don't have to?

Besides that, our solar system is otherwise quite rich. Middle-life, medium-sized star has a lot of mileage left. Being a single-star system, the planetary orbits and climates are naturally stable. Mercury has an enormous core of iron. Venus has a tremendous amount of energy stored and is a prime terraforming target for a civilization with the right technology.

We have 4 enormous gas giants, one of which forms a whole planetary system in and of itself, and could conceivably be collapsed into its own star.

The moon Titan is a giant ocean of liquid hydrocarbons.

This doesn't even get into the rich material wealth offered by the asteroid belt, Ceres, and Saturn's rings.

I'm sure there are better systems than ours from this perspective, but we're far from the bottom of the barrel. I'd sure as hell move here.

Another point is this, perhaps the potential of humans themselves presents a threat to another spacefaring civilization. What if they've seen species like ours rise up and conquer, and they'd prefer to nip it in the bud instead of waiting around for us to become more powerful?

No. It’s much better that there’s no one out there than we being the colonised.

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.

Doing exhaustive search of the universe is pretty big task; I don't think we can anytime soon determine that nobody is out there.

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

The unknown is the source of everything good and bad, useful and useless. It evokes fear and hope.

Fear of the unknown is what kept our smarter ancestors from getting eaten by bears without knowing what was in the cave first.