Участник:Dpopov/Песочница

On cosmological timescales, certain events in the future of the universe can be predicted with a level of accuracy. The following times all assume that the universe is open.

меньше 10,000 лет вперёд

• ~320 лет — Зона отчуждения Чернобыльской АЭС станет пригодной для жизни.
• ~600 лет — время, когда в соответствии с современными представлениями о границах созвездий, прецессия оси Земли сместит весеннее равноденствие из созвездия Рыб в созвездие Водолея. С этого события начнётся "Эра Водолея".
• ~1,000 лет — В результате прецессии земной оси Гамма Цефея станет Полярной звездой.
• 3,200 лет — В результате прецессии земной оси Йота Цефея станет Полярной звездой.
• 5,200 лет — Григорианский календарь начнёт отставать на один день от астрономического времени.
• 9,700 лет — Звезда Барнарда подойдёт на расстояние 3,8 светового года от Солнечной системы. В это время она будет нашей ближайшей соседкой.

от 10 000 до 1 000 000 лет вперёд

• 10,000 лет — конец человечества согласно теореме о конце света Брендона Картера, которая утверждант, что к этому моменту человечество вымрет с вероятностью 95%.
• 13,000 years — В результате прецессии земной оси Вега станет Полярной звездой.
• 36,000 years — time until Ross 248 passes between 3.024 light years of Earth, becoming the Sun's closest star.
• 42,000 years — Alpha Centauri becomes the nearest star system to the Sun once more.
• 50,000 years — according to the work of Burger and Loutre, time at which the current interglacial will end, sending the Earth back into an ice age, assuming limited effects of anthropogenic global warming. Also, time until Niagara Falls erodes away the remaining 20 miles to Lake Erie and ceases to exist.
• 100,000 years — time by which proper motion will render the constellations unrecognisable. Also, time by which the hypergiant star VY Canis Majoris will have exploded in a hypernova.
• 500,000 years — time by which Earth will most likely be impacted by a meteorite of roughly 1 km in diameter.

1 million to one billion (10⁶-10⁹) years from now

• 1.4 million years — Time until Gliese 710 passes within 1.1 light years of the Sun, potentially disturbing the Solar System's Oort cloud and increasing the likelihood of a comet impact in the inner Solar System.
• 10 million years — time by which the widening East African Rift valley will have been flooded by the Red Sea, causing a new ocean basin to divide the continent of Africa.
• 40 million years — estimated time until Mars's moon Phobos will collide with its surface.
• 50 million years — by this time, Australia will have crossed the equator and collided with Southeast Asia. Also, the Californian coast will begin to be subducted into the Aleutian Trench, and Africa will have collided with Eurasia, closing the Mediterranean Basin and creating a mountain range similar to the Himalayas.
• 100 million years — by this time, the Earth would likely have been impacted by a meteorite comparable in size to that which triggered the K-T extinction 65 million years ago.
• ~230 million years — beyond this time, the orbits of the planets become impossible to predict.
• ~240 million years — by this time, the Solar System will have completed one full orbit of the Galactic center.
• 250 million years — time until all the continents on Earth are fused into a new supercontinent.
• 600 million years — time until tidal acceleration moves the Moon far enough from Earth that total solar eclipses are no longer possible.

1 billion to 1 trillion (10⁹-10¹²) years from now

• 1 billion years — point at which the Sun's increasing luminosity will render life on Earth's surface impossible.
• 3.5 billion years — Time until surface conditions on Earth are comparable to those on Venus today.
• 3.6 billion years — estimated time until Neptune's moon Triton will fall through the planet's Roche limit, potentially disintegrating into a new planetary ring system.
• 5.4 billion years — time before the Sun becomes a red giant. During these times, it is possible that Saturn's moon Titan could achieve surface temperatures necessary to support life.
• 7 billion years — time until the potential collision between the Milky Way and Andromeda galaxies.
• 20 billion years — time until the end of the universe in the Big Rip scenario. Experimental evidence currently suggests that this will not occur.
• 50 billion years — time until the Earth and the Moon become tidelocked, with each showing only one face to the other, assuming both survive the Sun's expansion.
• 100 billion years — time until the universe's expansion causes all evidence of the Big Bang to disappear beyond the cosmic light horizon, rendering cosmology impossible.
• >400 billion years — time by which all the Solar System's actinide elements will have decayed to less than 1% their current value, leaving bismuth as the heaviest traceable element.

1 trillion to 1 decillion (10¹²-10³³) years from now

• 10¹² (1 trillion) years — low estimate for the time until star formation ends in galaxies as galaxies are depleted of the gas clouds they need to form stars.^, §IID.
• 2×10¹² (2 trillion) years — time until all galaxies outside the Local Supercluster are no longer detectable in any way, assuming that dark energy continues to make the Universe expand at an accelerating rate.
• 10¹³ (10 trillion) to 2×10¹³ (20 trillion) years — lifetime of the longest-lived stars, low-mass red dwarfs. ^§IIA.
• 10¹⁴ (100 trillion) years — high estimate for the time until star formation ends in galaxies.^, §IID. This marks the transition from the Stelliferous Era to the Degenerate Era; once star formation ends and the least massive red dwarfs exhaust their fuel, the only stellar-mass objects remaining will be stellar remnants (white dwarfs, neutron stars and black holes.) Brown dwarfs will also remain. ^§IIE.
• 10¹⁵ (1 quadrillion) years — estimated time until planets are detached from their orbits. Whenever two objects pass close to each other, the orbits of their planets can be disrupted and the planets can be ejected from orbit around their parent objects. Planets with closer orbits take longer to be ejected in this manner on average because a passing object must make a closer pass to the planet's primary to eject the planet.^{, §IIIF, Table I.}
• 10¹⁹ to 10²⁰ years — the estimated time until 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. The lower-mass objects can gain enough energy in this manner through repeated encounters to be ejected from the galaxy. This process will cause the galaxy to eject the majority of its brown dwarfs and stellar remnants.^{, §IIIA;, pp. 85–87}
• 10²⁰ years — estimated time until the Earth's orbit around the Sun decays via emission of gravitational radiation, if the Earth is neither first engulfed by the red giant Sun a few billion years from now nor ejected from its orbit by a stellar encounter before then.
• 10³² years — the smallest possible value for the proton half-life consistent with experiment.

1 decillion to 1 millinillion (10³³-10³⁰⁰³) years from now

• 3×10³⁴ years—the estimated time for all nucleons in the observable universe to decay, if the proton half-life takes its smallest possible value.
• 10³⁶ years—the mean half-life of a proton according to some theories.
• 10⁴¹ years—the largest possible value for the proton half-life, assuming that the Big Bang was inflationary and that the same process that makes protons decay made baryons predominate over anti-baryons in the early Universe.^, §IVA.
• 3×10⁴³ years—the estimated time for all nucleons in the observable universe to decay, if the proton half-life takes the largest possible value, 10⁴¹ years, consistent with the conditions given above. By this point, if protons do decay, the Black Hole Era, in which black holes are the only remaining celestial objects, will begin.
• 10⁶⁵ years—Assuming that protons do not decay, estimated time for rigid objects like rocks to rearrange their atoms and molecules via quantum tunnelling. On this timescale all matter is liquid.
• 2×10⁶⁶ years—the estimated time until a black hole with the mass of the Sun decays by the Hawking process.
• 1.7×10¹⁰⁶ years—the estimated time until a supermassive black hole with a mass of 20 trillion solar masses decays by the Hawking process. This marks the end of the Black Hole Era. Beyond this point, 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.
• 10¹⁵⁰⁰ years— Assuming protons do not decay, the estimated time until all matter decays to iron-56. See isotopes of iron.

Beyond 1 millinillion (10³⁰⁰³) years from now

• $10^{10^{26}}$ years^[a]— low estimate for the time until all matter collapses into black holes, assuming no proton decay. Subsequent Black Hole Era and transition to the Dark Era are, on this timescale, instantaneous.
• $10^{10^{50}}$ years—estimated time for a Boltzmann brain to appear in the vacuum via a spontaneous entropy decrease.

• $10^{10^{76}}$ years— high estimate for the time until all matter collapses into neutron stars or black holes, again assuming no proton decay.
• $10^{10^{120}}$ years— high estimate for the time for the universe to collapse into a sink, or terminal vacuum.

• $10^{10^{10^{76.66}}}$ years—scale of an estimated Poincaré recurrence time for the quantum state of a hypothetical box containing an isolated black hole of stellar mass. This time assumes a statistical model subject to Poincaré recurrence. A much simplified way of thinking about this time is that in a model where our universe's history repeats itself arbitrarily many times due to properties of statistical mechanics, this is the time scale when it will first be somewhat similar (for a reasonable choice of "similar") to its current state again.

• $10^{10^{10^{10^{2.08}}}}$ years—scale of an estimated Poincaré recurrence time for the quantum state of a hypothetical box containing a black hole with the mass within the presently visible region of our universe. This time assumes a statistical model subject to Poincaré recurrence. A much simplified way of thinking about this time is that in a model where our universe's history repeats itself arbitrarily many times due to properties of statistical mechanics, this is the time scale when it will first be somewhat similar (for a reasonable choice of "similar") to its current state again.

• $10^{10^{10^{10^{10^{1.1}}}}}$ years—scale of an estimated Poincaré recurrence time for the quantum state of a hypothetical box containing a black hole with the estimated mass of the entire universe, observable or not, assuming a certain inflationary model with an inflaton whose mass is 10⁻⁶ Planck masses.

Notes

^{^}  Beyond this point, years are used for convenience, though the numbers involved are so great that standard units are effectively meaningless.

See also

• Detailed logarithmic timeline
• Timeline of the Big Bang
• Terasecond and longer
• Timeline of natural history
• Earth's location in the universe