The solar system is stable for at least the next 100,000 years

It’s nice to have a feel-good story once in a while, so here’s one to ward off the existential fear: Earth isn’t in danger of being thrown into deep space for at least 100,000 years. In fact, all planets in the solar system are safe during this time, so there is good news all around, for you and your favorite planetary body.

Maybe it’s worth stepping back a bit. The likelihood of Earth, or any planet, being thrown out of orbit is always slim. As Newtonian physics tells us, a moving object stays moving unless it is acted upon by another force – and for something the size of a planet, it would take a large force to derail a planet. . But there are examples of planetary shuffling in the solar system’s own history. One of the most widely accepted models of solar system formation, the nice modeldescribes how the outer planets migrated early in the solar system’s history and are said to have wreaked havoc on the inner rocky worlds, displacing or even swallowing smaller proto-planets in the process.

But now researchers have do the math to show that such a migration is unlikely in the next 100,000 years. Angel Zhivkov and Ivaylo Tounchev from the Department of Mathematics and Computer Science at Sofia University in Bulgaria used computer calculations to determine that the planets are likely to remain stable. Their eccentricities (how much their orbit differs from circular) will remain small, as will their inclination (how far above or below the plane of the solar system they travel). Likewise, the semi-major axes (the radius of the longest part of an elliptical orbit) will not change significantly for any of the planets.

The semi-major axis of a planetary orbit. Image credit: Sndeep81, Wikimedia Commons.

Even the decommissioned dwarf planet Pluto was included in this study, and die-hard Pluto fans will be happy to know that it, too, will likely only wobble a little over the next 100,000 years.

So what happens after 100,000 years? The further in time you go, the more difficult predictions become, as the real Universe is still a bit chaotic, but Zhivkov and Tunchev believe that “with simple additional reasoning and evaluations…the theorem could be proven for a million years.” “. There are unlikely to be any problems during this time either. And, if you’re really worried, all it would take is additional computing power beyond what was accessible to researchers, and “the stability of the solar system could be proven for the next five billion years,” say -they.

Of course, the model is not perfect. It doesn’t take relativistic effects into account, and the math assumes that the planets are point masses, which of course in real life they aren’t. But perhaps the most glaring omission from the calculation concerns the millions of smaller bodies in the Solar System: asteroids, comets and everything in between. On their own, the gravitational effects of these objects are negligible, but as a collective, over billions of years, they could definitely shake the planets up a bit. Including them all in the model would be a monumental task, and one with diminishing returns. It’s not something that should keep you up at night.

A simulation of all known near-Earth objects as of January 2018. The solar system is a busy place – luckily most objects are tiny, with lots of empty space separating them from us and each other. Credit: NASA/JPL-Caltech.

So Earthlings, Martians and Jovians: breathe and enjoy the ride. The next 100,000 years around the Sun will pass smoothly. Don’t forget the sunscreen!

Learn more:

If you would like to read the article yourself, the preprint is available at ArXiv.

Featured image: True color representation of the planets. Credit: CactiStaccingCrane, Wikimedia Commons.

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