raginrayguns:
Forest fires are so weird. On what other planet do you just suddenly have such a violent chemical reaction? Idk probably none cause on what other planet do you have a bunch of carbon-carbon bonds sitting immersed in a bunch of oxygen? It’s not a stable situation, and after the fire has to be restored with solar power
Venus!
Fun Venus fact: it has fewer craters on its surface than you’d expect, and they all look suspiciously young. As far as we can tell, the whole surface of Venus is not that much more than a half billion years old. So what makes this so?
It is Earth-sized, which is theoretically enough to sustain tectonic activity. But we don’t see traditional plates there. Remember that Earth’s tectonic plates come in two flavors: continental plates, which are long-lived and low density, floating high in the mantle, and oceanic plates, which are heavier, younger, and are continually refreshed, spreading out from the center of the oceans and being subducted back in to the mantle where they collide with the continents.
As an incidental consequence, this means that a lot of ocean water gets sucked up in to the mantle during the subduction process. Water is very much unstable at tectonic pressures and temperatures, so it usually finds its way back out to the surface as a volcanic gas or something, but in the meantime there’s enough of it down there to lubricate the movement of the plates. Basically on the same principle that makes wastewater injection cause small earthquakes during the fracking process.
Now, Venus is likely to have had liquid water oceans at some point, but the runaway greenhouse effect has long since boiled them off. This means that a)the weight of the oceans doesn’t land disproportionately on a subsets of the plates, and b)there’s no water being pulled down there to keep the plates well-greased. So nowadays on Venus, subduction just… doesn’t happen. The plates are too rigid and dry, too homogeneous. So they stay locked in place relative to one another.
That means Venus has volcanoes but not really earthquakes. The energy that would be released in the motion of plates just builds, and builds, and builds. Until it doesn’t any more. Every [n] hundred million years or so, Venus has its one earthquake, which carries all the accumulated energy of all the earthquakes that ever happened on Earth between now and the Cambrian era, all at once.
This is enough to melt the entire surface and then some. The whole crust, all the mountains and valley networks and continents and basins and everything that floats on the fluid mantle, is subducted all at once, falling back in the planet’s interior. Then, with the whole planet molten, the surface can cool enough to form a new crust.
Anyway, that’s why global warming is bad.
