Climate collapse, Fermi paradox
How fucked up would it be to find ruins of a highly technological civilization on Venus?
Venus is totally in the habitable zone (although it has very long days) and the only reason it's so hot is because its dense CO2-rich atmosphere. What if once it had sentient life and they started a runaway global warming...?
@uint8_t They have bounced some pretty serious radar off of Venus - like, transmitted with the 300m Arecibo dish. But it's a long way away, and artificial satellites can be small. How long they could last, well, many of our satellites will come down soon but that's because we put them up as low as wee can get away with. The ones that are high up are going to be there a very long time.
@uint8_t Venus is actually a pretty comfortable place, a reasonable temperature, reasonably clear sky, just a bit acidic, at the one-atmosphere altitude. The ground is just a long way below that. But breathable air is a lifting gas on Venus, so there's this idea that you could build floating cities at the 1 atmosphere depth on Venus.
@uint8_t It certainly is possible for runaway global warming to occur, and it is thought to have happened to Venus - the oceans would have boiled, and the water vapour would have added to the greenhouse effect until it escaped to interplanetary space. At that point the result is really irreversible. It seems like maybe we can't make it happen here:
@kragen @anne Deuterium is an isotope of hydrogen. Heavy water (D2O) has a slightly higher boiling point, lower vapor pressure, and lower mean speed, so if you got an ocean with a H2O-D2O mixture, the concentration of D2O increases as you boil the water away. Our oceans have a higher D2O concentration than our rivers.
@kragen @jasper @uint8_t So the article describing the measurement is: https://www.ncbi.nlm.nih.gov/m/pubmed/17783310/
Terrestrial spectroscopy cast some doubt on the result but Venus Express seems to confirm it:
The deuterium enrichment is thought to have occurred because hydrogen is lost more easily to space; fortunately the Earth doesn't lose a lot of hydrogen because it's mostly in water and the "cold trap" keeps that too low for photodissociation.
All friendly creatures are welcome. Be excellent to each other, live humanism, no nazis, no hate speech. Not only for nerds, but the domain is somewhat cool. ;) No bots in general! (only with prior permission)