Well now, the Mayan calendar proved to be just that.. a calendar they had not finished (no computers). Y2k came and went.. so when does the world, at least as we know it, end?
The Earth will become uninhabitable in 1.75 billion years.
Why? We will no longer be in the habitable zone located around our parents star, the Sun. While we are moving away from the Sun at a rate of about half of a foot per year, this is not the reason the Earth will die out. Our end will be met with fire, not ice. We won’t be too far, we will be too close. However, with the Earth moving away from the Sun, albeit slowly, our problem will be the fact that we will be located too close in about 1.75 billion years.
How is this possible? The Sun is old. A lot of the stars and clusters we see in the sky, such as the bright star Rigel in the Orion constellation, are young. Rigel is a blue supergiant star that being fusing hydrogen (into helium) about 10 million years ago. The Sun is over 4 BILLION years old, and has another 4-6 billion years to go.
As the Sun ages it acquires more mass and thus expands. In a couple billion years it will be substantially larger and will begin to make ice and water around the globe evaporate. However, Mars should be lucky enough to be habitable.. so if we are not traveling on an interstellar level by then, there is that option.
The human race, as it stands now, has only been in existence for 200,000 years, give our take a few. So fear not.. if we were to live until this doomsday (the first based on scientific data of the Earth and our star and aside the human race’s knack for destroying itself), the human race will have existed 1,750,000,200,000 years. A little further math, just for fun, reveals our species has only lived about 0.00001148% of the total time we are expected to exist. Now, this figure is assuming that us being around for the last 200,000 years is accurate.. as well as the Earth exiting our Sun’s habitable zone in 1.75 billion years. If both those tidbits of educated guessing are more or less on point, then my 0.00001148% figure is accurate.
Amazing, right? Modern humans have come a very long way in just 2,000 years, so if we survive ourselves whilst trending upward on the intelligent life ladder, there should be nothing to fear. Will we? Probably not. However, I would not count us out just yet. These are very amazing times we live in. In 1969 the world was captivated by the Apollo missions success in putting boots on the Moon. Somehow that has made us take the technological leaps and other accomplishments for commonplace. We got spoiled. But it is truly astounding if you only take a moment to put it all in perspective.