how long before the earth is consumed by the sun?

Answer 1

Predictions as to the life expectancy of stars are based on the hydrogen to helium ratio in their composition (established by spectroscopic analysis). Currently the sun is 75% hydrogen and 25% helium.

When the sun enters its red giant phase in 4-5 billion years time (assuming it follows the conventional career of a G2 Main Sequence star) it will have lost a lot of mass by converting hydrogen to helium in fusion reactions and its gravitational pull on the planets will therefore be less.

It is therefore anticipated that the earth will spiral out to a larger orbit and avoid being consumed as the sun expands. That is the good news, However it will become heat-scorched, lose its atmosphere and will be rendered uninhabitable by life as we know it,

If humanity is to survive it will need to decamp to Titan, and get its nitrogen-based atmosphere to start developing oxygen from plant life (that means water).

However we have lots of time to solve the bio-engineering problems involved.

Considering it is only a hundred years since the Wright Brothers first got man into the air in 1903 and it only took another 66 years to get man to the Moon , getting manned flights to Titan should not be impossible, as technology develops.

The big issue is not only growing food and creating a breathable atmosphere but being able to make building materials from raw materials found on Titan, we cannot forever be importing solar panels and Buckminster Fuller domes from Earth!

"Sustainable communities" will have to be the motto for the first colonists,

It is a bit like a landlord giving us 5 billion years notice of seeking repossession of our home!

Answer 2

The sun has been fusing hydrogen into helium for about 5 billion years and has enough hydrogen left to burn for another 5 billion years. The changes in the sun will start to happen sooner than that, perhaps as "soon" as 3 billion years from now. Once it has fused all the hydrogen in the shell around its helium core, there's not enough gravity pressure to maintain nuclear fusion and the nuclear furnace shuts down, Gravity pressing inward then gets the upper hand by weighing down on the core of helium "ash" and compressing it -- there's no more nuclear fusion to provide outward pressure. The helium core gets ridiculously hot from all that pressure (1000 million degrees Kelvin maybe) and at that point the helium core ignites, swelling the sun into a Red Giant, swallowing Mercury and maybe even Venus. The Earth's oceans would start to boil off at that point. Mars will become nice and warm, hopefully develop some breathable air with the melting of its polar ice caps. The sun's helium core will burn much faster than the hydrogen, and when the nuclear furnace shuts down again, for a final time, the Red Giant will contract into what is called degenerate matter -- a White Dwarf, about the size of a small moon, and it will cool for a long, long, loooooong, long time. If the sun were more massive, it would burn faster but a lot more exotic, interesting stuff would be created in its core. Earth's gold, for example, must have come for a massive star that went supernova, something our sun will never do. Oh, and urbancoyote -- that galaxy is in the constellation Andromeda, not in Orion.

Answer 3

about 5 billion years from now, the sun is a fairly middle aged star, having a life span of about 10 billion years. Also, we're not even sure if the sun will engulf our planet, it could, or else it could just consume the first 2 planets... either way the earth will become desolate..

Answer 4

5 Million Years. We are in the Sun's last 5 - 10 % of life . So you could consider the Sun right now, a geriatric person.

Answer 5

Right around 5 billion years from now.

Around the same time! A galaxy will cross THROUGH the Milky Way and scramble our galaxy and some of its solar systems. This galaxy is currently located in Orion, but it's headed our way.

The human race will not be arond to see these fireworks. We don't have to worry about them affecting us.

Answer 6

Something on the order of a billion years, when the sun, having exhausted the hydrogen fuel in its center, becomes a red giant.

Answer 7

It's successfully orbited the sun for ~4.5 billion years, so I would guess never, that's because the sun will probably implode long before we lose orbit. Unless of course something catastrophic happens to change this.

Answer 8

A couple of billion years. No need to worry.

Answer 9

If you lived where I do You would think it is occurring now. Dang it's hot, 102 today.

Answer 10

every 28 days