Until now, a string of apocalyptic disaster movies like 2012 and The Day After Tomorrow seemed pretty silly and implausible. As it turns out, Hollywood directors might be onto something. According to scientists around the world, Earth will only be able to sustain life for another 1.75 to 3.25 billion years before the planet is expected to stray too close to the sun and burn up into nothing but hot rock.
How did the scientists come up with such an exact number, you ask? Earth sits in the habitable zone of the solar system where liquid water exists. For now, Earth is one of the Universe’s few Goldilocks planets that’s just close enough to the Sun that its water remains unfrozen; it’s also far enough away to prevent from being vaporized into a sun-baked rock like Mercury.
That’s all going to change in the future, according to the scientists, and it’s already been happening for a while. Like everything else, our sun is growing older. As this happens, planets can be pushed out of their original alignment. Currently Earth is still in the inner edge of the habitable zone, but as our yellow dwarf star slowly ages into a red sun, the zone moves outwards at a rate of one meter per year.
The scientists estimate that Earth has already been in this habitable zone for 6.3 billion to 7.8 billion years, which means it has already endured 70 percent of its span as a life-supporting planet. After a few billion years Earth will drift into what astronomers call the hot zone, where oceans, liquid water, and life in general cease to exist.
Images © NASA