YEARS FROM NOW: 100,000,000
All the continents on Earth may fuse into a supercontinent. Three potential
arrangements of this configuration have been dubbed Amasia, Novopangaea, and Pangaea Ultima.
The supercontinent (Pangaea Ultima, Novopangaea, or Amasia) will likely have rifted apart
Estimated time until a gamma ray burst, or massive, hyperenergetic supernova, occurs within 6,500 light-years of Earth;
close enough for its rays to affect Earth's ozone layer and potentially trigger a
mass extinction, assuming the hypothesis
is correct that a previous such explosion triggered the Ordovician–Silurian
extinction event. However, the supernova would
have to be precisely oriented relative to Earth to have any negative effect.
Carbon dioxide levels fall to the point at which C4 photosynthesis is no longer possible.
Free oxygen and ozone disappear from the atmosphere. Multicellular life dies out.