Poof! The Earth disappears--what happens to the atmosphere?

I originally was wondering how fast and in what directions, at first, it would dissipate–with the vague notion/idle thought of how long before I, relatively still in microgravity, would be able to breath.

So there’s that.

Then I thought of the water cycle and reflective heat and all that other good stuff that would be shot to hell.

Any one want to bat that around? I think I’d learn a lot about a lot.

This sounds like a question for Randall Munroe, and I recommend you send it to him (at whatif@xkcd.com).

My first guess is that initially there would be a movement of gas towards the empty spot where the Earth had been, since a moment before the Earth was removed, the surface was keeping the atmosphere from going downwards - but I could be wrong. Long-term, I doubt there’s enough atmospheric mass to hold itself together, so in the long term, the atmosphere will disperse into nothingness.

The solar wind will disperse it in very short order.

Good point.

When you lost the Earth did you lose the hydrosphere (the oceans and seas) as well? This would make a significant difference to conditions in the dissipating atmosphere.

You’re wrong. The atmosphere was trying to go downwards, yes. But downwards is a function of gravity. No Earth. Practically no gravity. Unless you just meant that there’d now be a sharp division between a region with air at 1 atmosphere and a magical vacuum. In which case you’re correct, that would take some of it, but it would also expand outwards.

The gravity of the Earth’s atmosphere alone would be 8.5 x 10e-6 m/s; less than a millionth of a gee, so the atmosphere would dissipate quite rapidly.


Yes, I was thinking of that in light of trying to get my head around how stars form, how immense “gas clouds” act Out There.

You’ve molecules slamming each other right and left in the atmosphere, but atoms alone (?) are smacking around also in the gas-collapses-on-it’s own-mass in both cases, right?

This is a side thought, just general threads from thinking about our instantly Earth-bereft atmosphere. Similar to wondering how the constituent parts of the atmosphere–O2,N,H2O, would sort themselves out in the statistical shuffle under the new conditions. Would they wind up each in their own area?

At ground level the volume directly beneath your feet would suddenly become a near-vacuum, so you would be caught in a hurricane as the atmosphere rushed into the space. Hmm; this would resemble a shockfront in some ways - you would be blown along with it as it gradually thins out. Don’t know how long you could breathe, however.