To predict the sun’s long-term evolution, researchers from Tōhō University in Japan and NASA employed mathematical models and sophisticated supercomputers.

According to their predictions, by the year 1,000,002,021, life on Earth will be extinct due to the sun’s increasing brightness and heat, which would boost global temperatures and progressively lower oxygen levels.

They also discovered that the sun would reach its red giant phase, which is when it runs out of hydrogen fuel and undergoes a massive expansion, in roughly five billion years. The inner planets, such as Mercury, Venus, and possibly Earth, will thereafter be swallowed up by the enlarged red giant.

Musk is still pushing for Mars colonisation, even though this cosmic destination is still a long way off.

“Mars is life insurance for life collectively,” he told Fox’s Jesse Watters on Monday.

“The sun is gradually expanding, and so we do at some point need to be a multi-planet civilization because Earth will be incinerated.”

Although the Sun is currently less than halfway through its life and is predicted to live for another five billion years, NASA has long cautioned that the Sun will ultimately run out of energy.

The study, which was published in Nature Geoscience, found that scientists developed year-by-year models to forecast changes in the composition of gases and climate. To predict the end of the world, they ran over 400,000 simulations.

They discovered that these shifts will be fuelled by the sun’s increased brightness, which will make Earth’s climate unstable. A mass extinction would occur on Earth as a result of oxygen depletion, according to the study. Consequently, the number of creatures that produce oxygen will decrease, and this process will continue until the only organisms left are anaerobic bacteria, which are organisms that can survive without oxygen.

With oxygen levels above 1% of current levels, scientists calculated using a random-based approach that Earth’s atmosphere will persist for around 1.08 billion years, give or take 0.14 billion years.

As ‘the basic fork in the road of destiny,’ Musk is keen to make sure Mars is ‘sufficiently self-sustaining’ throughout his lifetime. Musk frequently explains his long-term goals using the “fork in the road” analogy, as he did when he took over Twitter.

Musk said on Monday his mission for Mars is for it to one day “grow by itself if the resupply ships from Earth stop coming for any reason, whether that is because civilization died with a bang or a whimper.”

“If the resupply ships are necessary for Mars to survive, then we have not created life insurance. We’ve not created life insurance for life collectively.”

“So that’s the key point in the future where [the] destiny of life, as we know it, will forever be affected, is when Mars becomes self-sustaining.”

President Trump’s approval of a significant change in NASA’s financial objectives, including the biggest budget decrease in the agency’s history, was the first step towards assisting Musk in achieving this ambitious objective. The $6 billion that would have funded research, ISS operations, and upcoming missions, like as the Mars Sample Return (MSR) mission, was cut by the Trump administration on May 1.

The goal of that project, which has already cost NASA billions, was to return samples gathered by the Martian rovers to Earth for analysis. However, the reduction will enable NASA to invest more than $1 billion in manned space missions, guaranteeing ‘that America’s human space exploration endeavours remain unrivalled, innovative, and efficient.’

The main objective of Musk’s rocket company, SpaceX, is to land the first humans on Mars, and the White House proposal highlights how crucial it is that NASA beat China back to the moon.