# Timeline of the far future

Illustration of a black hole. Most models of the far future of the Universe suggest that eventually these will be the only remaining celestial objects.[1]

While predictions of the future can never be absolutely certain,[2] present scientific understanding in various fields has allowed a projected course for the farthest future events to be sketched out, if only in the broadest strokes. These fields include astrophysics, which has revealed how planets and stars form, interact and die; particle physics, which has revealed how matter behaves at the smallest scales, and plate tectonics, which shows how continents shift over millennia.

All predictions of the future of the Earth, the Solar System and the Universe must account for the second law of thermodynamics, which states that entropy, or a loss of the energy available to do work, must increase over time.[3] Stars must eventually exhaust their supply of hydrogen fuel and burn out; close encounters will gravitationally fling planets from their star systems, and star systems from galaxies.[1] Eventually, matter itself will come under the influence of radioactive decay, as even the most stable materials break apart into subatomic particles.[4] However, as current data suggest that the Universe is flat, and thus will not collapse in on itself after a finite time,[5] the infinite future potentially allows for the occurrence of a number of massively improbable events, such as the formation of a Boltzmann brain.[6]

These timelines cover events from roughly eight thousand years from now[a] to the farthest reaches of future time. A number of alternate future events are listed to account for questions still unresolved, such as whether humans survive, whether protons decay or whether the Earth will be destroyed by the Sun's expansion into a red giant.

## Key

Event is determined via
Astronomy and astrophysics
Geology and planetary science
Particle physics
Mathematics
Technology and culture

## Future of the Earth, the Solar System and the Universe

Years from now Event
36,000 The small red dwarf star Ross 248 passes within 3.024 light years of Earth, becoming the closest star to the Sun.[7] It will recede after about 8,000 years, making first Alpha Centauri and then Gliese 445 the nearest stars[7] (see timeline).
50,000 The current interglacial period ends, according to the work of Berger and Loutre,[8] sending the Earth back into a glacial period of the current ice age, assuming limited effects of anthropogenic global warming.

Niagara Falls will have eroded away the remaining 32 km to Lake Erie, and ceased to exist.[9]

50,000 The length of the day used for astronomical timekeeping reaches about 86,401 SI seconds, due to lunar tides braking the Earth's rotation. Under the present-day timekeeping system, a leap second will need to be added to the clock every day.[10]
100,000 The proper motion of stars across the celestial sphere, which is the result of their movement through the galaxy, renders many of the constellations unrecognisable.[11]
100,000[b] The hypergiant star VY Canis Majoris will have likely exploded in a hypernova.[12]
100,000[b] Earth will likely have undergone a supervolcanic eruption large enough to erupt 400 km3 of magma.[13]
250,000 Lōʻihi, the youngest volcano in the Hawaiian–Emperor seamount chain, rises above the surface of the ocean and becomes a new volcanic island.[14]
500,000[b] Earth will have likely been hit by a meteorite of roughly 1 km in diameter, assuming it cannot be averted.[15]
1 million[b] Earth will likely have undergone a supervolcanic eruption large enough to erupt 3,200 km3 of magma; an event comparable to the Toba supereruption 75,000 years ago.[13]
1 million[b] Highest estimated time until the red supergiant star Betelgeuse explodes in a supernova. The explosion is expected to be easily visible in daylight.[16][17]
1.4 million The star Gliese 710 passes as close as 1.1 light years to the Sun before moving away. This may gravitationally perturb members of the Oort cloud, a halo of icy bodies orbiting at the edge of the Solar System, thereafter increasing the likelihood of a cometary impact in the inner Solar System.[18]
8 million The moon Phobos comes within 7,000 km of Mars, the Roche limit, at which point tidal forces will disintegrate the moon and turn it into a ring of orbiting debris that will continue to spiral in toward the planet.[19]
10 million The widening East African Rift valley is flooded by the Red Sea, causing a new ocean basin to divide the continent of Africa.[20]
11 million The ring of debris around Mars hits the surface of the planet.[19]
50 million The Californian coast begins to be subducted into the Aleutian Trench due to its northward movement along the San Andreas Fault.[21]

Africa's collision with Eurasia closes the Mediterranean Basin and creates a mountain range similar to the Himalayas.[22]

100 million[b] Earth will have likely been hit by a meteorite comparable in size to the one that triggered the K–Pg extinction 65 million years ago.[23]
230 million Beyond this time, the orbits of the planets become impossible to predict due to the limitations of Lyapunov time.[24]
240 million From its present position, the Solar System completes one full orbit of the Galactic center.[25]
250 million All the continents on Earth may fuse into a supercontinent. Three potential arrangements of this configuration have been dubbed Amasia, Novopangaea, and Pangaea Ultima.[26][27]
400–500 million The supercontinent (Pangaea Ultima, Novopangaea, or Amasia) will have likely rifted apart.[27]
500–600 million[b] 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.[28]
600 million Tidal acceleration moves the Moon far enough from Earth that total solar eclipses are no longer possible.[29]
600 million The Sun's increasing luminosity begins to disrupt the carbonate–silicate cycle; higher luminosity increases weathering of surface rocks, which traps carbon dioxide in the ground as carbonate. As water evaporates from the Earth's surface, rocks harden, causing plate tectonics to slow and eventually stop. Without volcanoes to recycle carbon into the Earth's atmosphere, carbon dioxide levels begin to fall.[30] By this time, they will fall to the point at which C3 photosynthesis is no longer possible. All plants that utilize C3 photosynthesis (~99 percent of present-day species) will die.[31]
800 million Carbon dioxide levels fall to the point at which C4 photosynthesis is no longer possible.[31] Multicellular life dies out.[32]
1 billion[c] The Sun's luminosity has increased by 10 percent, causing Earth's surface temperatures to reach an average of ~320 K (47 °C, 116 °F). The atmosphere will become a "moist greenhouse", resulting in a runaway evaporation of the oceans.[33] Pockets of water may still be present at the poles, allowing abodes for simple life.[34][35]
1.3 billion Eukaryotic life dies out due to carbon dioxide starvation. Only prokaryotes remain.[32]
1.5–1.6 billion The Sun's increasing luminosity causes its circumstellar habitable zone to move outwards; as carbon dioxide increases in Mars's atmosphere, its surface temperature rises to levels akin to Earth during the ice age.[32][36]
2.3 billion The Earth's outer core freezes, if the inner core continues to grow at its current rate of 1 mm per year.[37][38] Without its liquid outer core, the Earth's magnetic field shuts down,[39] and charged particles emanating from the Sun strip away the ozone layer, which protects the Earth from harmful ultraviolet rays.[40]
2.8 billion Earth's surface temperature, even at the poles, reaches an average of ~420 K (147 °C, 296 °F). At this point life, now reduced to unicellular colonies in isolated, scattered microenvironments such as high-altitude lakes or subsurface caves, will completely die out.[30][41][d]
3 billion Median point at which the Moon's increasing distance from the Earth lessens its stabilising effect on the Earth's axial tilt. As a consequence, Earth's true polar wander becomes chaotic and extreme.[42]
3.3 billion 1 percent chance that Mercury's orbit may become so elongated as to collide with Venus, sending the inner Solar System into chaos and potentially leading to a planetary collision with Earth.[43]
3.5 billion Surface conditions on Earth are comparable to those on Venus today.[44]
3.6 billion Neptune's moon Triton falls through the planet's Roche limit, potentially disintegrating into a planetary ring system similar to Saturn's.[45]
4 billion Median point by which the Andromeda Galaxy will have collided with the Milky Way, which will thereafter merge to form a galaxy dubbed "Milkomeda".[46] The planets of the Solar System are expected to be relatively unaffected by this collision.[47][48] [49]
5.4 billion With the hydrogen supply exhausted at its core, the Sun leaves the main sequence and begins to evolve into a red giant.[50]
7.5 billion Earth and Mars may become tidally locked with the expanding Sun.[36]
7.9 billion The Sun reaches the tip of the red-giant branch of the Hertzsprung–Russell diagram, achieving its maximum radius of 256 times the present day value.[50] In the process, Mercury, Venus and possibly Earth are destroyed.[51]

During these times, it is possible that Saturn's moon Titan could achieve surface temperatures necessary to support life.[52]

8 billion Sun becomes a carbon-oxygen white dwarf with about 54.05 percent its present mass.[50][53][54][e]
20 billion The end of the Universe in the Big Rip scenario, assuming a model of dark energy with w = −1.5.[55] Observations of galaxy cluster speeds by the Chandra X-ray Observatory suggest that this will not occur.[56]
50 billion Assuming both survive the Sun's expansion, by this time the Earth and the Moon become tidelocked, with each showing only one face to the other.[57][58] Thereafter, the tidal action of the Sun will extract angular momentum from the system, causing the lunar orbit to decay and the Earth's spin to accelerate.[59]
100 billion The Universe's expansion causes all galaxies beyond the Milky Way's Local Group to disappear beyond the cosmic light horizon, removing them from the observable universe.[60]
150 billion The cosmic microwave background cools from its current temperature of ~2.7 K to 0.3 K, rendering it essentially undetectable with current technology.[61]
450 billion Median point by which the ~47 galaxies[62] of the Local Group will coalesce into a single large galaxy.[4]
800 billion Expected time when the net light emission from the combined Milkomeda galaxy begins to decline as the red dwarf stars pass through their blue dwarf stage of peak luminosity.[63]
1012 (1 trillion) Low estimate for the time until star formation ends in galaxies as galaxies are depleted of the gas clouds they need to form stars.[4]

The universe's expansion, assuming a constant dark energy density, multiplies the wavelength of the cosmic microwave background by 1029, exceeding the scale of the cosmic light horizon and rendering its evidence of the Big Bang undetectable. However, it may still be possible to determine the expansion of the universe through the study of hypervelocity stars.[60]

3×1013 (30 trillion) Estimated time for the remnant Sun to undergo a close encounter with another star in the local Solar neighborhood. Whenever two stars (or stellar remnants) pass close to each other, their planets' orbits can be disrupted, potentially ejecting them from the system entirely. On average, the closer a planet's orbit to its parent star, the longer it takes to be ejected in this manner, because stars rarely pass so closely.[64]
1014 (100 trillion) High estimate for the time until normal star formation ends in galaxies.[4] This marks the transition from the Stelliferous Era to the Degenerate Era; with no free hydrogen to form new stars, all remaining stars slowly exhaust their fuel and die.[1]
1.1–1.2×1014 (110–120 trillion) Time by which all stars in the universe will have exhausted their fuel (the longest-lived stars, low-mass red dwarfs, have lifespans of roughly 10–20 trillion years).[4] After this point, the stellar-mass objects remaining are stellar remnants (white dwarfs, neutron stars and black holes). Brown dwarfs also remain.

Collisions between brown dwarfs will create new red dwarf stars on a marginal level: on average, about 100 will be present in the galaxy. Collisions between stellar remnants will create occasional supernovae.[4]

1015 (1 quadrillion) Estimated time until stellar close encounters detach all planets in Solar Systems from their orbits.[4]

By this point, the Sun will have cooled to five degrees above absolute zero.[65]

1019 to 1020 (10–100 quintillion) Estimated time until 90% – 99% of brown dwarfs and stellar remnants are ejected from galaxies. When two objects pass close enough to each other, they exchange orbital energy, with lower-mass objects tending to gain energy. Through repeated encounters, the lower-mass objects can gain enough energy in this manner to be ejected from their galaxy. This process eventually causes the galaxy to eject the majority of its brown dwarfs and stellar remnants.[4][66]
1020 (100 quintillion) Estimated time until the Earth collides with the black dwarf Sun due to the decay of its orbit via emission of gravitational radiation,[67] if the Earth is neither first engulfed by the red giant Sun a few billion years from now[68][69] nor subsequently ejected from its orbit by a stellar encounter.[67]
1030 Estimated time until those stars not ejected from galaxies (1% – 10%) fall into their galaxies' central supermassive black holes. By this point, with binary stars having fallen into each other, and planets into their stars, via emission of gravitational radiation, only solitary objects (stellar remnants, brown dwarfs, ejected planets, black holes) will remain in the universe.[4]
2×1036 The estimated time for all nucleons in the observable Universe to decay, if the proton half-life takes its smallest possible value (8.2×1033 years).[70][71][f]
3×1043 Estimated time for all nucleons in the observable Universe to decay, if the proton half-life takes the largest possible value, 1041 years,[4] assuming that the Big Bang was inflationary and that the same process that made baryons predominate over anti-baryons in the early Universe makes protons decay.[71][f] By this time, if protons do decay, the Black Hole Era, in which black holes are the only remaining celestial objects, begins.[1][4]
1065 Assuming that protons do not decay, estimated time for rigid objects like rocks to rearrange their atoms and molecules via quantum tunneling. On this timescale, all matter is liquid.[67]
5.8×1068 Estimated time until a stellar mass black hole with a mass of 3 solar masses decays by the Hawking process.[72]
1.9×1098 Estimated time until NGC 4889, the currently largest known supermassive black hole with a mass of 21 billion solar masses, decays by the Hawking process.[72]
1.7×10106 Estimated time until a supermassive black hole with a mass of 20 trillion solar masses decays by the Hawking process.[72] This marks the end of the Black Hole Era. Beyond this time, if protons do decay, the Universe enters the Dark Era, in which all physical objects have decayed to subatomic particles, gradually winding down to their final energy state in the heat death of the universe.[1][4]
10200 Estimated high time for all nucleons in the observable Universe to decay (if they don't via the above process), through any one of many different mechanisms allowed in modern particle physics (higher-order baryon non-conservation processes, virtual black holes, sphalerons, etc.), on time scales of 1046 to 10200 years.[4]
101500 Assuming protons do not decay, the estimated time until all baryonic matter has either fused together to form iron-56 or decayed from a higher mass element into iron-56.[67] (see iron star)
$10^{10^{26}}$[g][h] Low estimate for the time until all matter collapses into black holes, assuming no proton decay.[67] Subsequent Black Hole Era and transition to the Dark Era are, on this timescale, instantaneous.
$10^{10^{50}}$ Estimated time for a Boltzmann brain to appear in the vacuum via a spontaneous entropy decrease.[6]
$10^{10^{56}}$ Estimated time for random quantum fluctuations to generate a new Big Bang, according to Carroll and Chen.[73]
$10^{10^{76}}$ High estimate for the time until all matter collapses into black holes, again assuming no proton decay.[67]
$10^{10^{120}}$ High estimate for the time for the Universe to reach its final energy state.[6]

## Astronomical events

This is a list of extremely rare astronomical events after the beginning of the 11th millennium AD (Year 10,001)

Years from now Date Event
8,000
Earth's axial precession makes Deneb the North star.[74]
8,649 years, 163 days 20 August, 10,663 AD A simultaneous total solar eclipse and transit of Mercury.[75]
8,705 years, 297 days 10,720 AD The planets Mercury and Venus will both cross the ecliptic at the same time.[75]
9,254 years, 168 days 25 August, 11,268 AD A simultaneous total solar eclipse and transit of Mercury.[75]
9,560 years, 355 days 28 February, 11,575 AD A simultaneous annular solar eclipse and transit of Mercury.[75]
10,000
The Gregorian calendar will be roughly 10 days out of sync with the Sun's position in the sky.[76]
11,411 years, 191 days 17 September 13,425 AD A near-simultaneous transit of Venus and Mercury.[75]
12,000–13,000
The Earth's axial precession will make Vega the North Star.[77][78]
13,000
By this point, halfway through the precessional cycle, Earth's axial tilt will be reversed, causing summer and winter to occur on opposite sides of Earth's orbit. This means that the seasons in the northern hemisphere, which experiences more pronounced seasonal variation due to a higher percentage of land, will be even more extreme, as it will be facing towards the Sun at Earth's perihelion and away from the Sun at aphelion.[78]
14,000–17,000
The Earth's axial precession will make Canopus the South Star, but it will only be within 10° of the south celestial pole.[79]
13,218 years, 26 days 5 April, 15,232 AD A simultaneous total solar eclipse and transit of Venus.[75]
13,776 years, 41 days 20 April, 15,790 AD A simultaneous annular solar eclipse and transit of Mercury.[75]
18,859 years, 297 days 20,874 AD The lunar Islamic calendar and the solar Gregorian calendar will share the same year number. After this, the shorter Islamic calendar will slowly overtake the Gregorian.[80]
27,000
The eccentricity of Earth's orbit will reach a minimum, 0.00236 (it is now 0.01671).[81][82][i]
36,158 years, 205 days October, 38,172 AD A transit of Uranus from Neptune, the rarest of all planetary transits.[83][j]
46,886 years, 356 days 1 March, 48,901 AD The Julian calendar (365.25 days) and Gregorian calendar (365.2425 days) will be one year apart.[84][k]
65,158 years, 297 days 67,173 AD The planets Mercury and Venus will both cross the ecliptic at the same time.[75]
67,149 years, 138 days 26 July, 69,163 AD A simultaneous transit of Venus and Mercury.[75]
222,494 years, 17 days 27 and 28 March, 224,508 AD Respectively, Venus and then Mercury will transit the Sun.[75]
569,726 years, 297 days 571,741 AD A simultaneous transit of Venus and the Earth as seen from Mars[75]

## Spacecraft and space exploration

To date five spacecraft (Voyagers 1 and 2, Pioneers 10 and 11 and New Horizons) are on trajectories which will take them out of the Solar System and into interstellar space. Barring an unlikely collision, the craft should persist indefinitely.[85]

Years from now Event
10,000 Pioneer 10 passes within 3.8 light years of Barnard's Star.[85]
25,000 The Arecibo message, a collection of radio data transmitted on 16 November 1974, reaches its destination, the globular cluster Messier 13.[86] This is the only interstellar radio message sent to such a distant region of the galaxy. Assuming a similar mode of communication is employed, it should take at least as long again for any reply to reach Earth.
32,000 Pioneer 10 passes within 3 light years of Ross 248.[87][88]
40,000 Voyager 1 passes within 1.6 light years of AC+79 3888, a star in the constellation Camelopardalis.[89]
50,000 The KEO space time capsule, if it is launched, will reenter Earth's atmosphere.[90]
296,000 Voyager 2 passes within 4.3 light years of Sirius, the brightest star in the night sky.[89]
2 million Pioneer 10 passes near the bright star Aldebaran.[91]
4 million Pioneer 11 passes near one of the stars in the constellation Aquila.[91]
8 million The LAGEOS satellites' orbits will decay, and they will re-enter Earth's atmosphere, carrying with them a message to any far future descendants of humanity, and a map of the continents as they are expected to appear then.[92]

## Technology and culture

Years from now Event
10,000 Estimated lifespan of the Long Now Foundation's several ongoing projects, including a 10,000-year clock known as the Clock of the Long Now, the Rosetta Project, and the Long Bet Project.[93]
10,000 Humanity is likely to be extinct by this date, according to one version of Brandon Carter's controversial Doomsday argument, which argues that half of the humans who will ever have lived have probably already been born.[94]
100,000 – 1 million Fastest time by which humanity could colonize the 100,000 light-year galaxy and become capable of harnessing all the energy of the galaxy, assuming a speed of 0.1c or greater.[95]
5 – 50 million Time by which the entire galaxy could be colonised by means within reach of current technology.[96]

## Graphical timelines

For graphical, logarithmic timelines of these events see:

## Notes

1. ^ The precise cutoff point is 0:00 on Jan 1, 10,001 AD
2. This represents the time by which the event will most probably have happened. It may occur randomly at any time from the present.
3. ^ Units are short scale
4. ^ There is a roughly 1 in 100,000 chance that the Earth might be ejected into interstellar space by a stellar encounter before this point, and a 1 in 3 million chance that it will then be captured by another star. Were this to happen, life, assuming it survived the interstellar journey, could potentially continue for far longer.
5. ^ Based upon the weighted least-squares best fit on p. 16 of Kalirai et al. with the initial mass equal to a solar mass.
6. ^ a b Around 264 half-lives. Tyson et al. employ the computation with a different value for half-life.
7. ^ $10^{10^{26}}$ is 1 followed by 1026 (100 septillion) zeroes.
8. ^ Although listed in years for convenience, the numbers beyond this point are so vast that their digits would remain unchanged regardless of which conventional units they were listed in, be they nanoseconds or star lifespans.
9. ^ Data for 0 to +10 Myr every 1000 years since J2000 from Astronomical solutions for Earth paleoclimates by Laskar, et al.
10. ^ Calculated using Aldo Vitagliano's Solex software. 2011-09-30.
11. ^ Manually calculated from the fact that the calendars were 10 days apart in 1582 and grew further apart by 3 days every 400 years.

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