Is the solar system stable? In relative human and historical terms, it is pretty stable, but small gravitational influences can cause dramatic effects due to the chaotic and complex nature of the forces involved. Now, two researchers have set out to see how easily it can be disrupted. And the answer is fascinating.
For the solar system to go truly wrong, the average distance between Neptune and the Sun only needs to be changed by 0.1 percent, which increases the likelihood of the solar system devolving into chaos tenfold.
The work is accepted for publication in the Monthly Notices of the Royal Astronomical Society and can be read on the paper repository ArXiv.
the smallest of the planets, could be one of the starting points for the solar system’s instability. Mercury’s perihelion – the closest point on a planet’s orbit around the Sun – moves by about 1.5 degrees every 1,000 years, which is very close to Jupiter’s own rate.
If the two come into resonance, there’s a one percent chance Mercury will be yanked out of orbit and either ejected from the Solar System or set on a collision course with Venus, the Sun, or even Earth over the next three to four billion years.
Allowing things to evolve naturally is fine, but there may be ways to create such instability and disrupt the Solar System.
A passing star
could get a little too close for comfort, according to the scientists. Mercury is too close to the Sun to be affected, but Neptune would, and the disruption would spread throughout the Solar System.
In just 20 million years, the effects of a 0.1 percent perturbation – equivalent to 4.5 million kilometers (2.8 million miles) in Neptune’s semi-major axis – spread to Earth and Mars. A perturbation of 10 percent could mean catastrophe for us and the Red Planet.
The team ran 2,880 simulations,
with 960 having perturbations that were too small to measure. Nonetheless, Mercury collided with Venus in four of them. There are 26 models that end with chaos unfolding, a lot of collisions between Mercury and Venus, one with Earth and Mars slamming into each other, and some where Uranus, Neptune, or Mercury are thrown out completely.
The team also calculated the likelihood of a star getting close enough to cause all of this, and we can sleep soundly that there are only about 20 chances in the next 100 billion years.
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