<b>In 42,000 years</b>, Alpha Centauri (pictured) becomes the nearest star system to the Sun once more, as nearby Ross 248 recedes. (NASA)
<b>50,000 years from now</b>, the current interglacial period ends, according to the work of Berger and Loutre, sending the Earth back into a glacial ice age. Niagara Falls erodes away to Lake Erie and ceases to exist. (Alves Gaspar)
By then, the length of the day used for astronomical timekeeping reaches about 86,401 seconds, thanks 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.
<b>In 100,000 years, </b>Earth will likely have undergone a supervolcanic eruption large enough to blast 100 cubic miles of magma from the gorund. (Ivan Alvarado/Reuters)
<b>Within 500,000 years</b>, Earth will have likely been hit by a meteorite roughly three-quarters of a mile in diameter -- assuming it cannot be averted. (David A. Hardy)
<b>1 million years </b>is the highest estimated time until the red supergiant star Betelgeuse explodes in a supernova. The tremendous blast is expected to be easily visible in daylight. (ESO/L. Calçada)
<b>In 8 million years</b>, the moon Phobos comes within 4,300 miles 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. (NASA/JPL-Caltech/University of Arizona)
<b>50 million years from now</b>, the Californian coast begins to be pulled into the Aleutian Trench due to its northward movement along the San Andreas Fault. Africa's collision with Eurasia closes the Mediterranean Basin and creates a mountain range similar to the Himalayas. (NOAA)
<b>After 240 million years</b>, the solar system completes one full orbit of the galactic center (pictured) from its present position. (2MASS/G. Kopan, R. Hurt)
<b>By the year 250,000,000 AD</b>, all the continents on Earth may fuse into a supercontinent. Three potential arrangements of this configuration have been dubbed Amasia, Novopangaea, and Pangaea Ultima (pictured). (C. R. Scotese (U. Texas at Arlington), PALEOMAP/NASA)
<b>600 million years from now</b>, tidal acceleration moves the moon far enough from Earth that total solar eclipses are no longer possible. (NASA)
By then, 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. By this time, they will fall to the point at which C3 photosynthesis is no longer possible. Almost all plants will die. (SOHO - EIT Consortium, ESA, NASA)
<b>After 1.3 billion years</b>, complex, "eukaryotic" life dies out due to carbon dioxide starvation. Only prokaryotes (pictured, largely single-cell creatures) remain. (Mariana Ruiz Villarrea)
After 3.3 billion years, there is a 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. (Lynette R. Cook/UCLA)
Even if they don't collide, <b>in 3.5 billion years</b>, surface conditions on Earth are comparable to those on Venus today. (NASA)
<b>After 5.4 billion years</b>, with the hydrogen supply exhausted at its core, the sun begins to evolve into a red giant -- one of the last stages in its life. (NASA/NRL)
And <b>in 8 billion years</b>, the sun becomes a carbon-oxygen white dwarf with about 54.05 percent of its present mass. (NASA)
<b>110–120 trillion years</b>: 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). After this point, the only objects remaining are stellar remnants (white dwarfs, neutron stars and black holes). Brown dwarfs (pictured) also remain. (NASA/JPL-Caltech)
<b>3×1043 years: </b>Estimated time for all nucleons in the observable universe to decay (if a number of cosmic assumptions are correct). The Black Hole Era, in which black holes are the only remaining celestial objects, begins. (NASA)
<b>1.7×10</b><b>106</b> years: Supermassive black holes themselves decay. Beyond this time, the universe enters the Dark Era, in which all physical objects have decayed to subatomic particles, gradually winding down to their final energy state.