How Will the Universe End? | Space Time

TL;DR

The universe will eventually reach a state of eternal darkness.

Transcript

MATT O'DOWD: Thank you to Wix for supporting PBS Digital Studios. We live in an unusual age, the age when the stars still shine. We should count ourselves lucky. Nearly all of future history will be dark. But events will still unfold in that long-cooling blackness, and civilizations may endure. So how will the universe and its far-future denizens s... Read More

Key Insights

• In 100 trillion years, the last star will become a white dwarf and fade to black, marking the end of the Era of Stars.
• The universe will spend most of its time in darkness, moving towards maximum entropy and heat death.
• Future civilizations might harness energy from mechanisms like Hawking radiation to survive in the dark ages.
• All galaxies will eventually dissolve, with stars and planets scattered into the void or falling into black holes.
• Protons may decay, leading to a universe filled only with photons, electrons, and black holes.
• Black holes will eventually evaporate via Hawking radiation, leaving behind a void of elementary particles.
• If protons don't decay, matter could persist longer, but quantum tunneling will ultimately lead to iron stars.
• The universe may end as an expanding void, or dramatic events like the Big Rip or vacuum decay could occur.

Summary & Key Takeaways

• In 100 trillion years, the last star will fade, ending the Era of Stars. The universe will spend most of its time in darkness, moving towards maximum entropy and heat death, but future civilizations might survive by harnessing energy from cosmic mechanisms.

• Galaxies will dissolve over time, scattering stars and planets into the void. Protons may decay, leaving only photons, electrons, and black holes. Black holes will eventually evaporate, resulting in a void filled with elementary particles.

• If protons do not decay, matter could persist longer, but quantum tunneling will eventually lead to the formation of iron stars. The universe may end as an expanding void, or dramatic events like the Big Rip or vacuum decay could occur.