Graphical timeline from Big Bang to Heat Death

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From the Big Bang through the present day and well into the future, matter and dark matter in the universe is concentrated in stars, galaxies, and galaxy clusters. Therefore, the universe is not in thermodynamic equilibrium and objects can do physical work.[11], §VID. The decay time of a roughly galaxy-mass (1011 solar masses) supermassive black hole due to Hawking radiation is on the order of 10100 years,[12], so entropy can be produced until at least that time. After that time, the universe enters the so-called dark era, and is expected to consist chiefly of a dilute gas of photons and leptons.[11], §VIA. With only very diffuse matter remaining, activity in the universe will have tailed off dramatically, with very low energy levels and very large time scales. Speculatively, it is possible that the Universe may enter a second inflationary epoch, or, assuming that the current vacuum state is a false vacuum, the vacuum may decay into a lower-energy state.[11], §VE. It is also possible that entropy production will cease and the universe will achieve heat death.

Timeframe for heat death