Deep time
Compress the age of stars into a single human life, and the universe today is 5.04 days old.1
Time here runs on a logarithmic clock: each step is ten times longer than the last. Scroll, or use the ← → keys, to move from one moment to the next.
10−50 to 105 years after the Big Bang
The Primordial Era
The hot, dense young universe. Particles, then nuclei, then the first atoms. No stars yet.
Read about the Primordial Era10−43 seconds
η = −50.77
The Planck time
About 5.4 × 10−44 seconds after the Big Bang. Before this, our current physics cannot describe the universe at all: gravity and quantum mechanics would need a theory we do not yet have.
10−32 seconds
η = −39.50
Inflation ends
In the leading theory, space grew exponentially for a tiny fraction of a second, stretching quantum ripples into the seeds of every future galaxy. When it ended, roughly by 10−32 seconds in many models, the universe filled with hot particles.
10 microseconds
η = −12.50
Quarks become protons and neutrons
As the universe cooled below about two trillion degrees, free quarks and gluons bound into protons and neutrons.
3 minutes
η = −5.24
The first nuclei
Between about ten seconds and twenty minutes, protons and neutrons fused into helium, deuterium and a trace of lithium. Roughly a quarter of all ordinary mass became helium, a prediction that observations confirm.
Source: Particle Data Group: Big Bang nucleosynthesis review
380,000 years
η = 5.58
The universe becomes transparent
Electrons and nuclei combined into neutral atoms and light could travel freely for the first time. That light, stretched into microwaves, is the cosmic microwave background we map today.
106 to 1014 years after the Big Bang
The Stelliferous Era
The age of stars. Galaxies light up, planets form, and so does everything you have ever seen. We are here.
Read about the Stelliferous Era100 million years
η = 8.00
The first stars ignite
Simulations suggest the first stars formed within roughly 100 to 200 million years, in small clumps of dark matter and gas. Their light began the Stelliferous Era.
290 million years
η = 8.46
The earliest galaxies we have seen
Webb has confirmed galaxies shining less than 300 million years after the Big Bang, such as JADES-GS-z14-0, already bright and surprisingly large.
Source: Carniani et al. (2024), Nature
9.2 billion years
η = 9.96
The Sun and Earth form
A collapsing cloud of gas and dust formed the Sun and its planets about 4.57 billion years ago, when the universe was already two thirds of its present age.
13.8 billion years
η = 10.14
You are here
The universe is 13.787 billion years old, give or take 20 million years. Stars are still forming, though more slowly than at their peak about ten billion years ago.
Source: Planck 2018 results VI: cosmological parameters
Today19 billion years
η = 10.27
The Sun becomes a red giant
In about five billion years the Sun runs out of hydrogen in its core and swells into a red giant, before shedding its outer layers and settling as a white dwarf.
24 billion years
η = 10.38
The Milky Way meets Andromeda, maybe
Updated measurements give roughly even odds that our galaxy merges with Andromeda within the next ten billion years. A collision is no longer considered certain.
6 trillion years
η = 12.78
The smallest stars grow old
A red dwarf of a tenth of a solar mass burns hydrogen for about six trillion years, briefly turning blue before it fades. These are the last ordinary stars.
1014 years
η = 14.00
Star formation ends
Galaxies run out of gas and the last red dwarfs fade. The Stelliferous Era closes after about a hundred trillion years.
1015 to 1039 years after the Big Bang
The Degenerate Era
The stars are out. Mass is locked in white dwarfs, neutron stars and brown dwarfs, slowly cooling in the dark.
Read about the Degenerate Era1019 to 1020 years
η = 19.50
Galaxies evaporate
Over countless close encounters, dead stars are flung out of their galaxies or sink into the central black hole. Galaxies dissolve.
1034 to 1040 years
η = 38.00
Protons decay, if they can
Many theories predict that protons are unstable. Experiments show their lifetime exceeds 1034 years; if they do decay, white dwarfs and neutron stars slowly dissolve, ending the Degenerate Era near 1040 years.
1040 to 10100 years after the Big Bang
The Black Hole Era
Black holes are the last concentrations of mass, evaporating one by one through Hawking radiation.
Read about the Black Hole Era1067 years
η = 67.00
Stellar black holes evaporate
Hawking radiation slowly drains black holes. One with the mass of the Sun lasts around 1067 years before it vanishes in a final flash.
Source: Page (1976), Phys. Rev. D
10100 years
η = 100.00
The last black holes evaporate
The most massive black holes, tens of billions of solar masses, take around a googol years to evaporate. With them goes the last structure in the universe.
After 10101 years, with no end
The Dark Era
A thin, cold sea of photons and leptons in an endlessly expanding space.
Read about the Dark EraBeyond 10100 years
η = 104.00
The Dark Era
Only photons of enormous wavelength, neutrinos, electrons and positrons remain, drifting apart in an expanding space. Nothing much happens, for a very long time.
Notes and method
1. Adams and Laughlin place the end of the Stelliferous Era, when star formation stops and the last red dwarfs fade, at about 1014 years. Treat those 1014 years as a 100-year human life. The universe is 1.3787 × 1010 years old, so it has lived 1.3787 × 1010 / 1014 = 1.38 × 10−4 of that span. Multiplied by 100 years, that is 0.0138 years, or 5.04 days: about 121 hours.
On the full timeline, out to 10100 years when the last black holes evaporate, the same comparison gives 4.35 × 10−81 seconds, far shorter than the Planck time of 5.4 × 10−44 seconds.
Time is measured in cosmological decades, η = log10(t / 1 year), following Adams and Laughlin (1997). The age of the universe, 13.787 ± 0.020 billion years, is from the Planck 2018 results. Far-future events depend on assumptions about dark energy and particle physics that have not been tested; each moment links to its source.