Seems like a low risk approach for taking over a planet would be to just park a large shade between the planet and it's star then let it enter a deep freeze. Then you could just remove the shade and let the planet warm back up before settling down.
Kind of like the movie Sunshine, but with more believable physics.
Edit: as a bonus, it could take place in ~50-100 years, when global warming has gotten worse. The aliens could disguise their motives for a while, claiming to be there to help counteract global warming. Warnings from a lone scientist would be ignored. Then, as things start getting too cold, their true purpose would become clear to all.
Seemingly benevolent aliens just here to help us fix our mess, but ultimately just want to sneakily take our stuff, is fun trope. https://www.gateworld.net/sg1/s4/2010/
A good movie plot, but I imagine in reality it would be obvious from the start that this would be a possibility and no scientists would be caught off-guard when the shade just didn't get removed. I can be almost certain as well that large factions of humans would "know" (believe, based on no facts) that is was happening all along and there would be incredible conflict across Earth as we figured out how to deal with this gentle attack, even before it was certain that is was an attack.
If it was done without consent, then it is an attack, and it doesn't fu*cking matter whether it ends up causing physical harm (or even if the invaders genuinely thought they meant well).
Regardless of whether it ends up taking away somebody's sunlight forever, it's still robbing people of all their agency. That decision was never theirs to make.
"The Forge of God" by Greg Bear The Makers deploy a vast, self-replicating robotic spacecraft called the "Doomsday Rock" near Earth's sun. The purpose of this massive construct is to absorb energy from the sun, causing it to dim and ultimately leading to the freezing of Earth, thus rendering it uninhabitable.
Spoiler alert: in The Forge of God the Earth gets literally blown to pieces.
As an alternative - it could be the oil producing countries, not aliens - seeking shade earth to disrupt solar and wind energy, and return to oil dominance.
Step One: build a machine that can cool the Earth, solving global warming Once and For All.
Step Two: demand the governments of the Earth pay you $1 trillion to turn it off at the appropriate time.
Solving global warming, turning off the earth iceball machine when it's time? Easily worth $100 trillion. OP just has no supervillain potential.
"I demand the sum of... $1 million dollars!" -- Dr. Evil
It should give people pause that with all the push for more renewables in California and Germany, they now have among the most expensive electricity on Earth.
Perhaps building unreliable energy infrastructure dependent on favorable climatic conditions is not the greatest idea. Especially if there's going to be major climate change. How's Germany doing again with all its solar lol.
Interesting to think about:
* How much mass could be positioned at L1 before changing the gravitational proposition of L1?
* How large an object could be positioned at L1 before it exceeded the practical bounds of L1?
* Presumably the object would reflect rather than absorb solar radiation. How would it deal with other solar ejecta?As a bonus, the other aliens in the game didn't view destructive terraforming as equivalent to WMDs - you could do this without even declaring war.
It's a cookbook!
Then they come back a year later: "I have bad news: the timeline has been accelerated, you now have 10 years".
What to do? To whom shall we turn for a plan?
Let's see - Earth's radius is 6,378 km.
Area exposed to the sun therefore would be 6,378 * 6,378 * 3.14 = 127,731,695 [1]
If you wanted to block just 1% of the light, that would take a shade of 1 million square kilometers, which would be equivalent to a shade that is 1,130 km on a side.
Seems like it would be tough to do given all the dust and rocks floating around the sun. Also, you're only covering 1%, which is much less than cloud cover.
I'd assume you'd aim to block at the equator since that would have the most direct impact on the intensity of the sun over the course of a year.
[1] - I'm calculating the projection as a flat surface here, so the numbers aren't exact but close enough.
Edit: Seems I misread the Starship capacity. This is probably only to LEO. Its hard to estimate but going by the geostationary payload, it would be one third of that, so triple the amount of flights. At a cadence of 2 launches per week it would take 4.5 years to launch all of it. ( 450 launches / 2 launches per week / 50 weeks a year)
I'd guess it would be far more efficient to launch more of these into regular orbit than trying to assemble them out in L1 and keep them from drifting off, even though you would need to launch at least twice as many for the same amount of coverage.
I wonder if there's a solution that uses the dust and rocks. Maybe you nudge some near-Earth asteroid near L1 and then blow it up or something.
Technically you need a bit more than that, for its umbra to block out the entire photosphere over the entire Earth:
https://en.wikipedia.org/wiki/Tangent_lines_to_circles#Outer...
[1] See https://en.wikipedia.org/wiki/Orbital_speed#Planets
Honestly it's all kind of silly because distances are so vast. It makes little sense to travel to a distant star - much better to build space habitats in your own star system. And even if you were going to do that for some crazy reason, there's no shortage of uninhabited planets out there. There's no need to commit planetary genocide of an alien race. Also if you have that kind of tech level, space habitats make more sense than planets anyway. Finally if you seed distant star systems with your own species, you risk that species going to war with you later (see how that played out on Earth just across the oceans.)
Have you seen Earth? We've been hit with a big rock, we've turned out atmosphere into poison, and had several other mass extinctions, none of which sterilized the Earth.
Unless you mean a Theia-level rock to turn the entire surface into lava, but you risk changing the mass, composition, and satellite system of the planet. At that point it's a different planet entirely, so I don't know why you would expend all that energy. Just find another planet to live on.
We can't even "just clean up what survives" in the cleanest rooms on Earth, using techniques specifically intended to do that. Life is incredibly tenacious, I really don't think you're going to wipe it off a planet's surface without destroying the surface (and atmosphere, probably) of the planet in the process. And if that's acceptable - again, why wouldn't you just pick a barren planet.
Here is an idea for any writers reading this who want to break the violence cycle: whenever you feel you need to have a character kill another in a gratuitously violent way, twist the plot so that they instead end up having steamy sex. The readers will get an intense hormone rush that way too.
Maybe their own star system is not safe for them. Say a political or religious minority that the majority would like to exterminate.
> And even if you were going to do that for some crazy reason, there's no shortage of uninhabited planets out there. There's no need to commit planetary genocide of an alien race.
If they've got cheap and easy FTL, sure. But suppose they don't have FTL. They are going the slow way, using a generation ship. At launch they may only know that their destination has a habitable planet but not know if it has intelligent life already.
Their generation ship environment might not be reliable enough for them to want to risk trying to move on to another star if it turns out the first habitable plant already has intelligent life.
This is all from memory and frankly I’m finding it fun trying it recall it without confirming it haha
https://en.wikipedia.org/wiki/Stratospheric_aerosol_injectio...
They can use that same technology to create, on a whim, inhabitable structures of arbitrary size and composition around any star- converting gas giants (or gas clouds or the solar winds) into perfectly positioned and constructed habitats in ideal locations.
Competition over planets would probably be as foreign and incomprehensible to them as what occurred in the universe prior to the Planck epoch is currently to us.
"The plans for demolition have been available on Alpha Centauri which is only 4 light years away you know."
It's a tiny fraction of what's required for a proper Dyson sphere. And we know civilizations can afford those because we can no longer see their stars.
For anyone who's hung up on saving nickle, we could do a low budget Worldring² or even thriftier Shadow Squares®.
²Nivenlarry ®Larry NivenThat's a giant claim you just made like it's fact.
Dyson Spheres would be really obvious, emitting infrared radiation unlike normal stars.
You are correct. That is absolutely a thing I did.
Also correct. Even past that, we haven't been mass-cataloging stars long enough for a Dyson sphere to be constructed and remove a star from our view.
One man's poison is the same man's alcohol and mankind revolves around that.
It looks promising; I'll check it out. Appreciate the recommendation.
The infrared star stands out because it is different than normal stars.
These are really good points. I figured the flaw in my theory is we haven't had precision observation long enough for DS to get constructed. Also that if we noticed the disappearance of a star, that we'd attribute it to a DS and not some natural occluding object.
edit: SOHO is at L1