The Solar System 500,000,000 Years From Now | Unveiled

The Solar System 500 Million Years from Now

The lengths of time required to fully contemplate the universe are almost unimaginable for humans... Our history as a species seems like it amounts to a long stretch of time, but every event we’ve ever encountered - every achievement, invention, war and cultural landmark - has happened over just 300,000 years or so. By comparison, to chart the future of our solar system, we have to look much, much further ahead.

This is Unveiled and today we’re uncovering what the solar system will be like 500 million years from now.

For a better understanding of the timescale of our solar system, we can look at its formation and life up to this point. The solar system is about 4.5 billion years old. We also know that the universe itself is 13.8 billion years old, so it took a long time for the solar system to form in the first place. In the beginning, according to the Nebular Hypothesis, our particular corner of the cosmos was more simply a massive cloud of interstellar dust. Then the fundamental force of gravity - perhaps aided by a nearby supernova - caused parts of that cloud to separate and collapse into another object; the sun. The planets around the sun formed at different times according to their classifications. The first to arrive were the gas giants Jupiter and Saturn. The ice giants Uranus and Neptune followed some 80 million years later, before the rest of the inner, terrestrial planets appeared shortly after that. All in all, it’s thought that it took about 800 million years from the moment of its formation before the solar system experienced the birth of its very first life form that we know of.

Clearly, between then and now, a lot has happened, with life on Earth evolving within a star system that has itself been constantly changing. But, looking into the future - 500 million years into the future ­- there’s plenty more still to play out, and some of it with some serious repercussions. For example, between ten and fifty million years’ time, Mars’ moon Phobos is scheduled to pass close enough to its home planet that it will begin to disintegrate… with the resulting matter flattening out to form some Saturn-like rings around Mars. Not much of a problem for us on Earth, you might think? But, if humans still even exist in ten million years’ time (which is by no means a certainty), then it’s a good bet that we will’ve transformed into a multi-planet, space-faring society by then. So, anything which threatens life on Mars, would now also threaten us.

At this stage, then, we should naturally be scanning the skies for anything which might pose a danger to the solar system as a whole, rather than just to Earth. Still, it’s worth remembering that sometime within the next 100 million years, Earth is expected to be impacted by an asteroid with at least the same force as the one that caused the K-PG extinction, which killed three quarters of all plant and animal life 66 million years ago. Over the course of the next 500 million years, then, our little planet can probably expect multiple, cataclysmic events like this one… to the point that it could be rendered a totally different world, in terms of size, shape, terrain and climate.

As for other changes that just the Earth will go through, here are two particularly big ones. First, at around 180 million years into the future, it’s calculated that even the days on this planet - even the passing of time - will have changed… because a day will then be 25 hours long, because Earth’s rotation will’ve significantly slowed. Second, at between 250 to 500 million years from now, with or without a large impact event to shake things up, it’s predicted that another supercontinent will form on Earth’s surface - already dubbed Pangaea Ultima. The world map then will look very different to the world map now! In general, scientists think that supercontinents - like the ancient Pangaea - merge together and break apart in a cycle, and the earliest estimates say that we could be a mere quarter-billion years away from our next united landmass!

For the wider solar system, even as we understand it now the prospect of life existing elsewhere within it seems low. But, in 500 million years’ time, it looks as though the big picture will be even bleaker. Precisely when life in the solar system will end is a matter very much up for debate, but even the more optimistic outlooks tend not to look past one billion years from now - mostly because of the sun’s ongoing expansion and increasing luminosity. According to James Kasting, a planetary scientist at Penn State University, the extinction of life on Earth is likely to happen sooner rather than later. Kasting warns of breaking the Earth’s carbon dioxide “Compensation Limit”, when the balance between CO2 and Oxygen becomes unsustainable through photosynthesis which could, he predicts, result in up to ninety-five percent of all plant life dying off. At which point, all other life - as we currently understand it - won’t last long.

Without plants to generate oxygen and provide food, animals would either starve to death or become poisoned thanks to the lack of breathable air. The ozone layer might then deplete at an even faster rate, as well, allowing for much higher levels of radiation to breach Earth’s atmosphere and strike the now desert-like surface. Clearly, by this point, if humans still haven’t made it off of Earth and further away from the sun, then they’ll perish. The only life with even a slim hope of surviving on Earth (or anywhere else around the solar system) at this time would be simple, single-celled organisms. Our growing, scorching sun just wouldn’t be suitable as a host star anymore - unless, of course, humans have become advanced enough by that point to have tamed it with a Dyson Sphere (but that’s for another video!).

When, then, we imagine the solar system in 500 million years, what we’re really considering is what state the sun will be in. We often hear that in about five billion years the sun will explode out into a red giant, before dying and transforming into a white dwarf, and then a black dwarf. But it’s not as though things will just stay the same until then. In 500 million years’ time, the sun will be 5% more luminous than it is at the moment. It sounds a small percentage, but it will likely have changed almost everything about the terrestrial planets, especially. Mercury, Venus, Earth and Mars will have to endure increased temperatures, increased radiation and if they ever had an atmosphere to speak of, it will now have been plunged into chaos. Perhaps even the likes of Ceres, Vesta and Pallas in the Asteroid Belt will have become the most habitable locations in the solar system by then… but whether or not there will be anything left to live on them, is quite another matter!

When the red giant phase does eventually come, it’s predicted that Mercury, Venus and very possibly Earth as well will ultimately be consumed by their star. But their fate won’t have come without warning, and those warning bells will be ringing loud and clear around the solar system about 500 million years from now!