Indeed, the calculation is not exactly precise. With a strong wind at our planetary back, we could go as long as 3.25 billion years before the Earth will travel out of the solar system’s habitable zone and into the “hot zone.” We have only been around for 200,000 years, that is still a fairly generous amount of time.
The research can be found in the journal Astrobiology where the total time for the Earth in the habitable zone is calculated at 7.79 billion years. (Earth is estimated to be about 4.5 billion years old unless you are a creationist where you still believe we are only a few thousand years old.)
