Let’s say an Alien race arrives in the solar system, they’re on a mission to obtain resources for their interstellar war effort. They note the existence of intelligent life on earth and decide they’ll try and get their resources from elsewhere, being a relatively benign race. Except if there is any resources they can’t get elsewhere in the solar system, they’ll strip the Earth to get them.
They need:
water
organics (hydrocarbons)
loads of metals of all kinds
hydrogen / helium / other noble gases
rare earth elements
radioactives / trans-uranics
Anything else we can conceivably thing an advanced industrial society needs.
So is the Earth saved? Can they get everything else they need elsewhere in the solar system or are we doomed to be strip mined? In particular if some resource is available elsewhere in the solar system but the Earth has more of it than anywhere else put together we might still be in trouble…
No, they don’t need/want food from us, we & everything else on Earth is inedible to them.
As for other resources, I doubt it. Don’t forget about the Kuiper Belt & the Oort Cloud. Everything there is in nice bite size pieces, much easier to get at than strip mining the earth. The only thing that I can think of, that the Earth has more of is stupidness.
Someone will be along shortly to point out my wrongness.
Limestone? Since much of this is produced by biological processes and it is reactive enough to go away on geological time scales, probably not much of that around elsewhere.
Other than that, biological compounds. Snake venom and the like. All of these could be synthesized by a sufficiently advanced alien species, though, so they’d only need a few samples and not some destructive invasion.
The OP mentioned trans-uranics. Those, with the possible exception of a tiny bit of Neptunium (or is it Plutonium), are man-made as are Promethium and Technetium and some other radioactive isotopes. I’d assume they could make these as easily or more easily than we can, but they won’t be finding them elsewhere in the Solar System already available, I’m pretty sure.
Europa has about as much water as Earth does, and it’s probably not salty or polluted (by us). Well, it’s definitely not polluted by us. Not yet, anyway. Also, no pesky whales to filter out. There’s a lot of ice on top of it, though, but it’s also not so deep into a gravity well.
3.0 x 10^19 kg in Saturn’s rings.
1.4 × 10^21 kg in Earth’s hydrosphere (including freshwater).
So, Earth has 50 times more water on the surface than in all of Saturn’s rings. In fact, we still have more fresh water than everything in the rings. Most people seem to over estimate how much mass in those rings.
On the other hand, the Kuiper belt is probably a much better source of water than either. Find a suitably sized dirty snowball and haul it away. It’s all in one place, and you don’t have fight a whole planet worth of gravity.
Aren’t there hydrocarbons on several moons in the solar system (Titan maybe Hyperion)? Only thing I can think of is limestone, and it’s possible that it exists on Mars, though there isn’t any evidence that I know of saying so thus far. The only other things unique to the Earth would be lifeforms.