Scientists and philosophers have been preoccupied by the Solar System’s ultimate demise for centuries. Astronomers now know our Sun will transform into a dead lump of rock, in a thousand trillion years.
And way before then, in perhaps 100 billion years, the planets in the Solar System will have careened away across the galaxy.
Jon Zink of the University of California, Konstantin Batygin of California Institute of Technology and Fred Adams of the University of Michigan have now joined forces to forecast what exactly will happen as the Solar System meets its demise.
The trio said: “Understanding the long-term dynamical stability of the solar system constitutes one of the oldest pursuits of astrophysics, tracing back to Newton himself, who speculated that mutual interactions between planets would eventually drive the system unstable.”
However, attempting to solve what is known as the N-body problem is extraordinarily complicated, as the more bodies interacting with each other in a system, the harder it is to predict.
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“Given enough time, some of these flybys will come close enough to disassociate – or destabilise – the remaining planets.”
With these additional influences accounted for in their calculations, the team ran 10 N-body simulations for the outer planets, using the powerful Shared Hoffman2 Cluster.
These were split into two phases: up to the end of the Sun’s mass loss, and the consequential phase.
Although 10 is a rather weak statistical sample, the researchers discovered a similar scenario occurring each time.
After the Sun completes its evolution into a white dwarf – a star’s stellar core remnant – the outer planets have a larger orbit but remain relatively stable.
However, Jupiter and Saturn appear to become captured in a stable 5:2 resonance – for every five times Jupiter orbits the Sun, Saturn orbits twice.
These expanded orbits, as well as characteristics of the planetary resonance, make the system more susceptible to perturbations by passing stars.
Because of this, after 30 billion years, this can eventually create chaotic orbits, resulting in rapid planet loss.
Ultimately, by 100 billion years after the Sun turns into a white dwarf, the Solar System is finally at an end.
This is, therefore, a far shorter timeframe than proposed in 1999, but the researchers are at pains to point out if this remains contingent on current observations of the local galactic environment and stellar flyby estimates, both of which may change.