THEY are coming.... What would *really* happen?

[G'th]

So what do we think we own?

Im guessing we all think we own the earth (so no mining of it by aliens).

Im also guessing we think we own the moon.

Do we have first call on Mars? Jupiter? Kuiper Belt? Is the entire solar system ours?

I bet we would not like it if they were mining our solar system!!! But under our own rules for exploration (such as when Europeans were discovering the rest of the world), if you cant go there and dont have a settlement, you don't have such a good claim!

Do we even own earth??

A lot of sci-fi universes usually go by the rule that the dominant species of the solar system does effectively have jurisdiction over that system. I would imagine this would be how it would play out in real life, at least between peaceful species anyway. Any warmongering species probably wouldn't care unless they couldn't take the system.

[Seret]

Mainly because we didn't have planes yet. Now we have rockets, the Space Shuttle (according to far too many people) so they could as well. Plus every sci-fi movie will help scare people.

You're suggesting people at the time couldn't conceive of the Martians coming to visit us? Jules Verne was showing interplanetary flight in 1865, War of the Worlds was written in 1897. The idea had occurred to them, they just got on with their lives.

[xcorps]

A lot of sci-fi universes usually go by the rule that the dominant species of the solar system does effectively have jurisdiction over that system. I would imagine this would be how it would play out in real life' date=' at least between peaceful species anyway. Any warmongering species probably wouldn't care unless they couldn't take the system.[/quote']

Heh, I wrote a short story about that very thing. Miners come to Sol, make contact, mine the atmosphere of Jupiter. Earth gets uppity because it claims ownership. Miners laugh and say come get it.

[Ralathon]

A lot of sci-fi universes usually go by the rule that the dominant species of the solar system does effectively have jurisdiction over that system. I would imagine this would be how it would play out in real life' date=' at least between peaceful species anyway. Any warmongering species probably wouldn't care unless they couldn't take the system.[/quote']

I think most interstellar species will just leave inhabited systems alone. There are plenty of systems out there and most will consist of dead rocks that won't complain when you mine them. If you strip mine an inhabited system you are just going to .... off an entire species for the next few millenia and severely hamper their infrastructure. No asteroid mining is going to put a bit of a downer on your trip towards an interstellar civilization.

Why bother with the criticism and bad blood when you can just point your mining vessel towards random star #2453289.

[TheGatesofLogic]

I expect that a civilization capable of amassing the incredible resources needed for even "slow" interstellar travel would have any need for the paltry resources of earth,especially considering the low fraction of rare metals on its surface in comparison to the size of its gravity well. I would also suspect that such a civilization would require a centralized community and government to sustain such a massive undertaking. At such a point humanity is valueless as a species save for cultural purposes, unless humans are a marginally more rational or intelligent species (intelligence is different from technological level) however one would expect that factor would also be marginal considering our current rate of AI development.

[Dedjal]

I would be very ashamed of my species and tell them that, yes, human species are warmongering idiots with little to no common sense. And giving us hyperdrive etc. Would just provide the human species with a new way of building bombs and blasting ourselves into oblivion.

But there are some people on this planet that is not like that, though.

Take me with you, please...!

[magnemoe]

Agreed, EM radiation (ie, light) is the only thing that propagates in a vacuum. They will be sensing it, if not organically, then with technology (I suppose they might not have eyes, but they will have something like telescopes and cameras, that is for sure).

So, first question:

Did they know we were here when they left?

They'd likely be able to sense that there was something funny going on based on our oxygen atmosphere, and a prominant green pigment from a long way away - farther than our radio waves would be discernable. If they didn't know we were here when they departed, they'd know before they arrived.

One scenario: Its just a survey ship passing by, maybe looking to do some in situ resource utilization before going on the next leg of its journey - it may stick around for longer observation, or it may just transmit its findings and leave quickly

Another Scenario: They came to study what was producing the oxygen atmosphere - they may or may not make contact, if its obvious we've detected them, they probably would.

Another scenario: They came to colonize the system. Assuming they have fusion drives or better and have adapted to life in space (they may colonize systems with no terrestrial planets) such, they may prefer to start with small gravity wells - it start mining the asteroid belt and Kuiper belt, Earth, with all of its biohazards and its nearly 10 km/s dV requirments, and resources hidden deep underground, may not be attractive to them. However, its industrial output may be of interest to them. If we build stuff for them, they can grow their colony faster. I don't foresee direct enslavement - more like they give us technology, and we have to build stuff for them, perhaps this is arranged via "gunboat diplomacy" - accept, or they bombard us from beyond earth orbit (likely only delivered to governments in secret). Your enslavement is the amount of labor you do that goes towards paying taxes to fund the construction of stuff for the aliens.

Or they just acknowledge our claim to earth, but then claim everything in the system beyond earth orbit for themselves - maybe they'll be nice and let us have the moon too.

I wonder how humanity would react if we saw our potential future (expansion into space) robbed from us?

I don't see a relativistic kill weapon as likely. They are only good against civilizations that are limited to one system with a handful of planets. Civilizations spread across multiple start systems, with self sufficient industry on various asteroids/small moons/etc, could not be readily wiped out by 1 KE weapon. Earth would not pose an existntial threat to them if they're already expanding across start systems. If they're here, they're long past their single inhabited planet stage. A simple warning would suffice, and I think they'd want to study us (a technological space faring civilization wouldn't form if there wasn't some desire for knowledge, don't you think?).

Also, I'm assuming no warp drive. Sorry but I'd still wager that alcubierre drives are impossible, even if they don't strictly violate relativity and haven't been strictly proven to be.

They come, they study, they may or may not colonize the rest of the system, they may or may not seek to use Earth's industrial capacity for their benefit.

We are so small and insiginficant at this point, that we don't pose a threat, and the planet isn't worth much to them - mars would probabl be better suited for their needs anyway

They know we have an oxygen atmosphere, that make Earth interesting and worth an visit this is an error in many sci-fi stories, if you you have interstellar flight you also have good space telescopes, even if you have hyper drive an space telescope would be smart, and yes you would deploy it at the edge of your operational range

For the rest I assume slower than light.

They would know we have life, probably that we have complex life, they can see various ecosystems on earth, assuming an 100 meter telescope in the outer solar system.

And an advanced ecosystem will be very interesting to study, you will learn a lot about parallel evolution you might even find profitable products even if you can not eat it flowers from another star will sell well, templates for genetic manipulation will be more important.

An slower than light flight like this will have colonization as one of their objectives.

If they don't need planets they don't need to colonize here, might want to keep Earth as an base and resupply point if they are not interested in colonies, this is far cheaper if you can use the cheap local labor. Gunboat or simply apply for some patents if they are smart, carrot and stick combined works even better.

Relativistic kill weapons has two downsides, if you hit someone with an self supplied asteroid civilization you will get counter-fire. If you hit the outposts of an empire you will face return fire followed by an invasion fleet who would be pretty angry at you.

Note I guess an hit by an relativistic kill weapon will look pretty different than a huge asteroid so you don't even have to hit the empire for them to attack you.

[lajoswinkler]

We could try this.

[KASASpace]

Well, the most likely scenario is that a large probe will enter the solar system, perhaps fairly close to the sun, perhaps far. What will most likely be the case is an unmanned vehicle that will enter the solar system and then move towards the planets of the system and deploy smaller probes for long-term operations. Maybe a few probes for the Gas-planets to explore the moons, an Earth probe, Venus probe, Mars, etc.

Now, the design will probably be similar to the Daedalus concept, an interstellar staged spacecraft. Although that was designed for flybys, but with a solar sail coming close to the solar system you could possibly brake........

They will most likely come to gather science, like our probes but interstellar. Perhaps we could rendezvous with one of the probes and reverse engineer the propulsion system.

Earth is valuable for a few reasons, large amounts of Carbon, large amounts of Hydrogen in one place, so if you have fusion engines......

We're here, we have creative mind that can think up almost anything. We have an amazing adaptability trait that some other species may not possess in the universe.

Asteroids are useful for metals, however, metals may not be useful for an interstellar civilization, especially since metals can have reactions with radiation that spawns more radiation.

Edited July 29, 2014 by KASASpace

[JedTech]

They will most likely come to gather science, like our probes but interstellar. Perhaps we could rendezvous with one of the probes and reverse engineer the propulsion system.

or perhaps we already have...

[KASASpace]

or perhaps we already have...

Then we would have something pretty good.

[Rakaydos]

Hmm... you generally talk about gravity slingshots as something to get you out into interstellar space, but what if the alien probe timed it's arrival to slingshot jupiter to "capture" into Sol system, like you might use Laythe to capture into Jool orbit?

Since an interstellar slowboat probe has nothing but time, it then procedes to get on the Interplanetary Transport network and slingshots everywhere, beaming close up images and radio data back to the home system.

[KASASpace]

Hmm... you generally talk about gravity slingshots as something to get you out into interstellar space, but what if the alien probe timed it's arrival to slingshot jupiter to "capture" into Sol system, like you might use Laythe to capture into Jool orbit?

Since an interstellar slowboat probe has nothing but time, it then procedes to get on the Interplanetary Transport network and slingshots everywhere, beaming close up images and radio data back to the home system.

That's a good point. Although it would depend on a lot of factors, like where Jupiter is in the solar system (if you can get an encounter where the gravity of Jupiter can pull you towards the sun's retro grade vector, then it's possible.)

[Rakaydos]

That's a good point. Although it would depend on a lot of factors, like where Jupiter is in the solar system (if you can get an encounter where the gravity of Jupiter can pull you towards the sun's retro grade vector, then it's possible.)

They have a flight time of a few centuries. A little prograde/retrograde will put Jupiter wherever in it's orbit they want. A little more, and they can plan multiple planet alignments.

It's not like they wont know about gas giants in their destination system before they leave- we know as much already for plenty of exoplanet systems, and we cant even see them yet, just extrapolated their existance.

[Ralathon]

Hmm... you generally talk about gravity slingshots as something to get you out into interstellar space, but what if the alien probe timed it's arrival to slingshot jupiter to "capture" into Sol system, like you might use Laythe to capture into Jool orbit?

Since an interstellar slowboat probe has nothing but time, it then procedes to get on the Interplanetary Transport network and slingshots everywhere, beaming close up images and radio data back to the home system.

The best you can possibly get out of a slingshot maneuver is twice the orbital velocity of the planet/moon you use for the grav assist. That means you can get about 26 km/s of dV from Jupiter. If their probe was moving at 1% of the speed of light when it encounters jupiter that means it can shed 0.86% of its velocity via gravity assists. In other words, not enough to get captured by a loooooong shot.

If you want an interstellar probe to slow down into a capture orbit it needs some beefy propulsion system.

[Heimdall5008]

A very interesting thread. I will only reply to some of the later posts because it would be too long otherwise.

Earth is valuable for a few reasons, large amounts of Carbon, large amounts of Hydrogen in one place, so if you have fusion engines......

If I want hydrogen I would go for a gas giant. There I would get an almost infinite supply of very high concentrations of hydrogen in the upper atmoshere that I could also use for areocaputre. I think the real charm for a spacefaring race would be our oxygen and any complex organic compound a.k.a ressources you only get from an active biosphere. Everything else they will probbably find easier elsewhere.

They know we have an oxygen atmosphere, that make Earth interesting and worth an visit

Only if they are based on the same chemical setup. Maybe life on there planet does not need/produce oxygen and therefore they would not realize that oxygen is a sign of life.

If you want an interstellar probe to slow down into a capture orbit it needs some beefy propulsion system.

Or the have a really good heat shield for aerobraking

---

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But to come back to the intial question. From the viewing point of the aliens I think they will not expect earth to have a highly advanced civilazation (or at least what we see as one ). When the started the mission earth was most likely well before the industrilazation. Therefore they would have no way to detect a sentinent species from another star system. With the industrilazation an advanced might be able to detect the pollution of the atmospehre and later on the increased power output in the EM bands.

So when they first detect our (radio, TV, etc.) transmissions they will discover that on earth some intelligence is at work. They will probbably not understand the transmissions but they will sure detect the regular nature and that is always a good sign for something unnatural.

For the human side I suppose that it depends greatly who will discover the ship/probe. If a state (or a space agency) will detect it first, I think it is most likly that the politicians of this country will try to hide the discovery. Maybe even come up with a cover story what this signal is, in the hope to profit from the aliens. Any private organization or amateur will be very careful to puplish such a finding (or at least the assumption of aliens) because he has to fear that he will not be taken seriously. But sure engough soemtime it has to get out. After this I have really no idea what will happen. Maybe many people will deny the possibility and think of a fake.

[KASASpace]

They have a flight time of a few centuries. A little prograde/retrograde will put Jupiter wherever in it's orbit they want. A little more, and they can plan multiple planet alignments.

It's not like they wont know about gas giants in their destination system before they leave- we know as much already for plenty of exoplanet systems, and we cant even see them yet, just extrapolated their existance.

We actually know very little about the outer planets of those systems, because they might be taking too long to pass in front of the star for direct observation, or the "wobble" is so small due to distance that it's not observable.

[KASASpace]

A very interesting thread. I will only reply to some of the later posts because it would be too long otherwise.

If I want hydrogen I would go for a gas giant. There I would get an almost infinite supply of very high concentrations of hydrogen in the upper atmoshere that I could also use for areocaputre. I think the real charm for a spacefaring race would be our oxygen and any complex organic compound a.k.a ressources you only get from an active biosphere. Everything else they will probbably find easier elsewhere.

Actually gas-giants may not have hydrogen, but a lot of them do. However, that close to Jupiter the radiation is probably too extreme for almost any civilization's technology to survive.