Our Solar System Is Going to Totally Disintegrate Sooner Than We Thought
Although the ground beneath our feet feels solid and reassuring (most of the time), nothing in this Universe lasts forever.
One day, our Sun will die, ejecting a large proportion of its mass before its core shrinks down into a white dwarf, gradually leaking heat until it's nothing more than a cold, dark, dead lump of rock, a thousand trillion years later
But the rest of the Solar System will be long gone by then. According to new simulations, it will take just 100 billion years for any remaining planets to skedaddle off across the galaxy, leaving the dying Sun far behind.
Astronomers and physicists have been trying to puzzle out the ultimate fate of the Solar System for at least hundreds of years.
"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," wrote astronomers Jon Zink of the University of California, Los Angeles, Konstantin Batygin of Caltech and Fred Adams of the University of Michigan in their new paper.
But that's a lot trickier than it might seem. The greater the number of bodies that are involved in a dynamical system, interacting with each other, the more complicated that system grows and the harder it is to predict. This is called the N-body problem.
Because of this complexity, it's impossible to make deterministic predictions of the orbits of Solar System objects past certain timescales. Beyond about five to 10 million years, certainty flies right out the window.
But, if we can figure out what's going to happen to our Solar System, that will tell us something about how the Universe might evolve, on timescales far longer than its current age of 13.8 billion years.
In 1999, astronomers predicted that the Solar System would slowly fall apart over a period of at least a billion billion - that's 10^18, or a quintillion - years. That's how long it would take, they calculated, for orbital resonances from Jupiter and Saturn to decouple Uranus.
According to Zink's team, though, this calculation left out some important influences that could disrupt the Solar System sooner.
Firstly, there's the Sun.
In about 5 billion years, as it dies, the Sun will swell up into a red giant, engulfing Mercury, Venus and Earth. Then it will eject nearly half its mass, blown away into space on stellar winds; the remaining white dwarf will be around just 54 percent of the current solar mass.
This mass loss will loosen the Sun's gravitational grip on the remaining planets, Mars and the outer gas and ice giants, Jupiter, Saturn, Uranus, and Neptune.
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this article was publish on sciencealert.com
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