Removing a Planetary Atmosphere

[Sky Captain]

Society with large scale gravity manipulation tech probably could strip the atmosphere by projecting large mass near the planet that would suck atmosphere away although tidal effects affecting crust from something like that probably would be far more destructive than actual process of atmosphere removal.
If there is tech for planetary shields maybe it would be possible to create a planet encompassing shield at low altitude and then expand shield sphere pushing the atmosphere above the shield into space.

[Purple]

Now that does sound like a good idea. I wonder if I could have it so that the villain uses the planets own shields against them for bonus evil. Since you know, evil.

[Knife]

Hitting Earth with a gamma-ray burst at sufficiently close range would be enough to strip off enough atmosphere (particularly the bits that protect us from the worst of solar radiation). Sufficiently close being a few hundred parsecs. According to Phil Plait 100 light years would set the entire goddamn (he doesn't use the word "goddamn") planet on fire. So there are things that could get rid of the atmosphere, but they involve enormous stars exploding, neutron stars merging, or maybe even black holes merging. Poking about online, the energy release of a "typical" long-duration GRB is the same amount of energy that would be released if the 1/2000th of the sun were converted directly to radiation.

So basically, nothing any society could bring to bear on a planet, but astronomical events could pull it off. That or find a way to turn off the magnetosphere, like Broomstick suggested. That would take longer, but it would be pretty damned effective in the long run.

Pretty much what I was thinking, go Star Trek and blow up a neighboring star in a hyper nova and somehow aim the gamma burst towards target planet. A little extreme but...

[LaCroix]

What about a huge fleet of ships, landing (or using long hoses/gravitonic beams/teleporters), filling up with liquified air and flying off?

If it was a nomadic race like the ID4 aliens, but only interested in filling their oxigen/nitrogen/co2 tanks, they would do it without a blink or a thought about the biome. On the way out, they took the mayority of Nickel-Iron and silicate asteroids with them (easier than mining the earth for ressources).

As in - not a weapon system, but someone who went shopping and destroyed an insignificant planetary civilization because he couldn't care less.

[InsaneTD]

That might work if nitrogen isn't available elsewhere that uninhabited. But for oxygen/CO2, it'd be easier to just harvest ice balls, melt the ice and then, if it's water, use electrolysis to harvest the oxygen out of it. You'd then have hydrogen for fuel or what ever to boot. CO2 isn't that hard to make but I'm sure there are better places to find it then the bottom of a gravity well.

[LaCroix]

Since our atmosphere is 80% nitrogen, it's probably the biggest source of it in this system, next to Titan.

[madd0ct0r]

That might work if nitrogen isn't available elsewhere that uninhabited. But for oxygen/CO2, it'd be easier to just harvest ice balls, melt the ice and then, if it's water, use electrolysis to harvest the oxygen out of it. You'd then have hydrogen for fuel or what ever to boot. CO2 isn't that hard to make but I'm sure there are better places to find it then the bottom of a gravity well.

easier, but if you are operating at a scale of entire planet atmospheres, you would be looking for a LOT.

[Sky Captain]

That might work if nitrogen isn't available elsewhere that uninhabited. But for oxygen/CO2, it'd be easier to just harvest ice balls, melt the ice and then, if it's water, use electrolysis to harvest the oxygen out of it. You'd then have hydrogen for fuel or what ever to boot. CO2 isn't that hard to make but I'm sure there are better places to find it then the bottom of a gravity well.

Or if that civilization has some kind of anti gravity tech which makes lifting off from deep gravity well with multi trillion ton payload a trivial task. If that is true then intruders most likely would search for biggest source of whatever they want and it could turn out harvesting from single large source is logistically easier than going after thousands of individual Kuiper belt ice balls.

[SpottedKitty]

Since our atmosphere is 80% nitrogen, it's probably the biggest source of it in this system, next to Titan.

Or maybe Pluto? No special equipment needed, just a shovel — the surface is covered in nitrogen ice.

[LaCroix]

Since our atmosphere is 80% nitrogen, it's probably the biggest source of it in this system, next to Titan.

Or maybe Pluto? No special equipment needed, just a shovel — the surface is covered in nitrogen ice.

As far as I know, Pluto is mostly rock and water ice, with only a bit of N ice on top, and a very thin N atmosphere. It certainly pales in comparison to Earth and Titan, who have a dense atmosphere. Triton even denser than earth and almost pure N.

Then, usually, your systems are optimized for one thing or the other. A system that handles liquid and gaseous N won't handle N ice too well. Also, no need to break it off the ground and into chunks your system can handle. You might theoretically be more efficient farming gaseous N over ice. N atmospheres are pretty common, afaik.