I wonder what surviving human held the record before balloons (excluding edge cases like jumping gaps on a mountain bridge). Probably it was someone falling from a cliff into snow or water, but maybe it involved something weird like a gunpowder explosion or volcano.
Ackchyually, IIRC without radioactive decay our planet would have cooled down below life-sustaining temperatures long before any complex life-forms would have had the chance to evolve
The part where it took 800 million years of before life evolved something to do with all that toxic oxygen that those damn cyanobacteria were producing was a particularly difficult hurdle.
Funny how that one never pops up in discussions of "great filters" - the Sun is 4.6 billion years, will burn out in another 5. Life spent almost 10% of that time repeatedly almost killing itself before some life form figured out how to use oxygen. What if that's the part where we got lucky, and that on average most habitable planets get stuck in this self-destructive oxygen cycle?
The sun heats the earth.
Yes, the core would have cooled down faster without radioactive decay. But it's not clear how that would affect surface temperatures or what effect that would have on life on earth.
It's true that the sun heats *the surface* of the earth and completely dominates the energy input there. However, we capture that heat due to having an atmosphere. Part of what maintains the atmosphere (over millions of years) is volcanic activity. Volcanic activity exists due to having a molten core. Also, life seems to have started at geothermal vents. So alltogether life would be radically different at the very least, and likely way more limited in its opportunities to evolve.
Somehow, this makes bishops appear the most peaceful as they comingle. But the pawns: put those vicious monsters in the farthest corner inside a double-walled enclosure. They eat everything!