10
12 (1 trillion) years ? low estimate for the time until star formation ends in galaxies as galaxies are depleted of the gas clouds they need to form stars.
10
20 years ? estimated time until the Earth's orbit around the Sun decays via emission of gravitational radiation, if the Earth is neither first engulfed by the red giant Sun a few billion years from now nor ejected from its orbit by a stellar encounter before then.
10
65 years ? estimated time for rigid objects like rocks to rearrange their atoms and molecules via quantum tunnelling, assuming that the proton does not decay. On this timescale all matter is liquid.
1.7 ?10
106 years?the estimated time until a supermassive black hole with a mass of 20 trillion solar masses decays by the Hawking process
10
1500 years ? the estimated time until all matter decays to 56Fe (if the proton does not decay).
10
10^50 years (yes, that a superscript on the superscript. Don't try to write that number down at home) Estimated time for a Boltzmann Brain to appear in the vacuum via a spontaneous entropy decrease.
A Boltzmann brain is a hypothesized self-aware entity which arises due to random fluctuations out of a state of chaos. The idea is named for thermodynamicist Ludwig Boltzmann (1844-1906), who advanced an idea that the known universe arose as a random fluctuation, similar to a process through which Boltzmann brains might arise.
Coolest theory I have heard this week.
