How cold would Earth be if the sun did not generate any heat?
It depends on what part of the Earth you are referring to. If the sun suddenly ‘blinked out’ the atmosphere would literally condense and fall to the ground and the surface temp would hover just a bit above absolute zero. However, this wouldn’t spell the end of life on the planet. Geothermal activity would go on as usual. The Earth’s core would continue to generate tremendous heat supporting extremeophiles and even liquid water. So the is, dig deep enough, stock up on food, and stay warm!
