What is most likely the ultimate fate of the planet Earth? question 2: About how long to astronomers think i?

Answer 1

The sun is growing brighter. Very, very slowly. About 10% every billion years or so.

This means that somewhere in the next billion or two years, the surface of the Earth will become completely uninhabitable to all life except those that can survive in volcanoes. The seas will all boil off in about 3.5 billion years, and the Earth will be not unlike Venus is now.

In six billion years, the Sun will run out of hydrogen and begin to fuse helium. This will cause it to change from a yellow-white star to a red giant. At that time it will expand to 100-200 times its current diameter and consume Mercury. Because it will have lost some mass, Venus and Earth can survive in further orbits (if models about mass loss are too generous, it is possible that Venus or even Earth are engulfed... this is not the leading theory, however).

Greater solar wind will completely blow away the Earth's (and Venus') atmosphere and growing heat will give it a surface temperature of 1600 degrees Kelvin.

When the sun runs out of helium a couple hundred million years later, it will not be able to make the next transition. Much of it's remaining material will blow into space as a kind of nebula and all that will remain will be a slowly burning white dwarf. All planetary orbits will move further out. Temperatures will be negligible.

After a trillion years or so even this nominal light will stop. The Sun's core will crystallize into a giant diamond.

Answer 2

The sun will become a Red Giant in approximately 5 billion years. However, our galaxy is predicted to collide with the Andromeda galaxy in approximately 3 billion years.

Prior to that, some very likely mass annihilators of humanity and possibly the world include: Global pandemic, ice age, meteorite collision, global nuclear war, massively destructive weather events, and the consequences of overpopulation.

Answer 3

The *ultimate* fate of the planet is that it will eventually be engulfed by our sun when it expands as a red giant. But that's supposedly millions (or perhaps billions) of years away...

Answer 4

In a couple of billion (1,000,000,000) years, long after humanity is gone and earth has lost its own rotation, getting boiled on one side and frozen on the other, it will be swallowed by the sun. Our planet will be inhabitable long, long before the sun kills it.

Answer 5

dec 2012