Premise: The collision of Theia, approximately 4.4 billion years ago, resulted in the transfer of just the right amount of radioactive elements (Uranium & Thorium, mostly) to provide for the perfectly balanced Carbon cycle we enjoy today.
Theia’s impact produced, not only the Moon (which is instrumental to Earth’s stability among other things) and not only gave Earth a much larger Iron/Nickel core (resulting in an oversized and critically necessary magnetosphere), but also transferred a Goldilocks amount of Uranium and Thorium to the Earth’s core to allow the Carbon cycle to exist.
Plate tectonics and vulcanism allow for sequestered Carbon (the sediment of billions of years of photosynthetic death and deposition) to be recycled into the atmosphere providing the perfect amount of CO2, turning Earth into the greenhouse paradise we enjoy today.
Without just the right amount of radioactivity, Earth’s core would either cool, ending the Carbon cycle (in addition to collapsing the magnetosphere) or boil the surface causing far too much vulcanism for life to exist on the planet.
This is just one more reason to accept that Earth is unique in the Universe and that Fermi’s Paradox is not a paradox at all.
We are probabilistically alone. 2^70 alone.