How long could humanity survive if the sun is destroyed?
The bulk of humanity probably freezes pretty quickly — only those with access to totally weatherproof dwellings and a good deal of energy survive the first few weeks. That’s just from the cold. Now, the earth isn’t going to cool to absolute zero, given that there’s quite a bit of heat from geothermal activity, but the question in my head is how long the atmosphere remains breathable even if very, very cold. There are two concerns I can think of. The most immediate is if the lowered temperature results in a viscosity problem (at what temperature would the gases in the atmosphere change state?). The second is the fact that all plant life is going to die and stop converting CO2 back into O2. Assuming there’s some way around that, small portion of humanity might survive as long as their food could hold off by taking advantage of a few geothermal hotspots. Of course, given that the ecosystem is totally wrecked, beats me how food gets found or produced. Maybe through a few non-wrecked ecosy
HyperBlue is referring to the time it would take us to notice given the speed of light limitations. I’m not knowledgeable enough to answer this but I did find an answer from an astro grad student at the MadSci network: You’re right. If the sun went out, the Earth would freeze over very quickly. However, human technology (warm clothes, houses, and burning things for heat) would probably keep many of us alive long enough to starve to death. The Sun warms the Earth’s atmosphere by about 15 degrees C per day. That amount is offset by infrared radiation, which cools the planet by the same amount. If the sun were to turn off, the cooling would continue, and the atmosphere would drop to freezing in just a few days. However, the warm water of the oceans represents a very large storage of heat. As the atmosphere cools, the oceans would give up this heat. My calculations suggest it would take about three months for the
It depends on what happens to the sun. If the sun explodes (goes nova/supernova/loses magnetic containment) there is a very slight chance we’d notice it before we all died. Anyone on the side of the planet that is facing the sun would be boiled away in an instant by the x-ray and gamma radiation released in such an event. People who are in underground bunkers on the side of the planet facing away from the sun would experience some really weird phenomena, including electrical arcing from metallic objects and hair standing on end and water boiling in glasses on the table and other extreme examples of ‘what radiation does to different things when things go pear shaped’ before they died of radiation poisoning. It would be a battle to see whether they lived long enough for the shock wave of the explosion to reach the earth. The planet would either disintegrate or would have every last bit torn off down to the iron core, but that would be a moot point because what’s left of the plasma that w
