Although the ground beneath our feet feels hard and soothing (most of the time), nothing in this universe lasts forever.
One day our Sun will die, discarding much of its mass, before its core shrinks into a white dwarf, gradually escaping heat until it becomes 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. According to the new simulations, it will take only 100 billion years for the other planets to deviate through the galaxy, leaving the dying Sun far behind.
Astronomers and physicists have been trying to puzzle the ultimate fate of the solar system for at least hundreds of years.
“Understanding the long-term dynamic stability of the solar system is one of the oldest pursuits in astrophysics, following Newton himself, who suggested that interactions between planets would eventually lead to system instability,”
But it’s much more complicated than it may seem. The greater the number of bodies involved in a dynamic system, interacting with each other, the more complex this system is and how much it grows and is more difficult to predict. This is called an N-body problem.
Due to this complexity, it is impossible to make deterministic predictions about the orbits of objects in the solar system after certain time scales. After about five to 10 million years, security flies straight out the window.
But if we can understand what will happen to our solar system, it will tell us something about how the universe can evolve, on a time scale far beyond its current age of 13.8 billion years.
In 1999, astronomers predicted that the solar system would slowly decay over a period of at least a billion billion – that’s 10 ^ 18, or quintillion – years. They calculated how long it would take for the orbital resonances from Jupiter and Saturn to separate Uranus.
However, according to Zink’s team, this calculation has ruled out some important influences that could disrupt the solar system earlier.
First, there is the Sun.
After about 5 billion years, while dying, the Sun will swell into a red giant, devouring Mercury, Venus and Earth. Then it will throw away almost half of its mass, blown into space by stellar winds; the remaining white dwarf will be about 54 percent of the current solar mass.
This mass loss will loosen the Sun’s gravitational grip on the other planets, Mars, and the outer gas and ice giants, Jupiter, Saturn, Uranus, and Neptune.
Second, as the solar system orbits the galactic center, other stars must come close enough to disrupt planetary orbits, about once every 23 million years.
“Taking into account the loss of stellar mass and the swelling of the orbits of the outer planet, these meetings will become more influential,” the researchers wrote.
“In time enough, some of these flights will get close enough to give up – or destabilize – the other planets.”
With these additional influences taken into account in their calculations, the team conducted 10 N-body simulations for the outer planets (leaving Mars to save calculation costs, as its influence must be negligible) using the powerful Hoffman2 shared cluster. These simulations were divided into two phases: until the end of the loss of mass of the Sun and the phase that follows.
Although 10 simulations are not a strong statistical sample, the team found that a similar scenario is played out each time.
After the Sun completes its evolution into a white dwarf, the outer planets have a larger orbit, but still remain relatively stable. However, Jupiter and Saturn are caught in a stable resonance 5: 2 – every five times Jupiter orbits the Sun, Saturn orbits twice (this possible resonance has been offered many times, not least by Isaac Newton himself).
These extended orbits, as well as the characteristics of planetary resonance, make the system more susceptible to interference from passing stars.
After 30 billion years, such stellar disturbances make these stable orbits chaotic, leading to the rapid loss of the planet. All but one planet avoid their orbits and flee into the galaxy like deceptive planets.
This last, lonely planet lingers for another 50 billion years, but its fate is sealed. In the end, it is also lost by the gravitational influence of passing stars. Eventually, 100 billion years after the Sun became a white dwarf, the solar system is gone.
This is a significantly shorter period than that proposed in 1999. And, researchers carefully note that this depends on current observations of the local galactic environment and predictions of stellar flight, both of which may change. So in no case is it engraved in stone.
Even if estimates of the solar system’s death timeline still change, it is still many billions of years old. Mankind is unlikely to survive long enough to see it.
The study was published in The Astronomical Journal.