A new NASA-backed simulation has revealed a deeply unsettling possibility — Earth could eventually be flung out of the Solar System entirely.
It has long been accepted that in around five billion years, the Sun will exhaust its hydrogen fuel and balloon into a red giant. In doing so, it will begin fusing helium, growing large enough to consume Mercury, Venus, and quite possibly Earth.
But a fresh study published in the journal, ‘Icarus’ — at Science Direct — suggests that our home planet might not even last that long.
As our Solar System journeys through the galaxy, it occasionally drifts near other stars. These stellar flybys might seem distant, but even from afar, their gravity can wreak havoc on planetary orbits.
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The new research, which models these interactions, shows that the situation is even more precarious than scientists previously believed. Earlier studies had hinted that slight disturbances in Neptune’s orbit could eventually eject Mercury. But this new simulation takes things a step further.
The research team estimates that stars will pass within one parsec (around 3.26 light-years) of the Sun roughly 19 times every million years. To put that into context, the closest star to us right now, Proxima Centauri, is about 4.25 light-years away.
When this frequency is simulated over the next five billion years, around 2 per cent of outcomes result in the loss of at least one planet.
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And when planets go missing, it’s not pretty.
In IFLScience’s summary of the study, it says: “Pluto has a 5 per cent chance of becoming unstable, as a consequence of the perturbation to the giant planet’s orbit,” the study reveals. Unsurprisingly, Mercury is the first in line — again.
The outlet added: “Orbiting so close to the Sun makes it the statistically closest planet to any other world in the Solar System. Not a good thing since the probability of instability increased by 50 to 80 per cent.”
But most chillingly for us, Earth is not immune. In fact, there’s a 1-in-500 chance — or 0.2 per cent — that our planet could be completely ejected from the Solar System, or smash into another world.
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If you’re hoping to escape to Mars, think again. The Red Planet fares slightly worse, with a 0.3 per cent chance of a similarly catastrophic fate.
Even worse, these scenarios don’t play out in the distant future we might expect. IFLScience further explained: “The simulation actually suggests that a planetary loss scenario happens sooner rather than later, making stellar field passage the main cause of instability in the Solar System for the next 4 to 4.5 billion years.”
Thankfully, there’s no need to panic just yet. The study notes that we’re not due for any particularly close stellar encounters for quite some time.
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Still, it’s a sobering reminder that space is a far more chaotic and unpredictable place than we often imagine.