The stability of the solar system depends on Neptune

Scientists from the University of Toronto simulated the method The passage of another star near the solar system can disturb the orbits of the planets. They found that even very slight perturbations in a planet’s orbit lead to a catastrophic streak – although they are rare.

Even a change in the orbit of the farthest planet in our system, Neptune, by just 0.1 percent makes the orbits of the other planets unstable, the researchers wrote in a research paper published on ArXiv. Site.

Such a change can occur due to the passage of a star of its mass in the solar system at a distance of 37 billion kilometers (about 250 astronomical units). Neptune orbits 4.5 billion kilometers from the Sun (or about 30 AU). Earth, by definition, is one astronomical unit, or about 150 million kilometers.

These disturbances are not a sudden disaster. The orbits of the planets slowly begin to “diverge”, but this is a process that takes tens or hundreds of millions of years.

The good news is that Only more than thirty simulations ended in cosmic catastrophe. Most of the time, Mercury’s orbit was unstable when it collided with Venus, and a few ended up ejecting Neptune or Uranus out of our system.

Only one Sim pointed out The instability of the Earth’s orbit that collided with Mars – But there’s also some solace here.

The areas around the solar system are not very crowded. The chances of a star approaching the sun within 250 AU are very small. Statistically, this happens every hundred billion years. Most stars are also much smaller than the Sun – three out of four in our galaxy are red dwarfs.

By the motion of the stars, astronomers can deduce whether such a close encounter occurred in the past.

The closest to our system was Gliese 710. Today it is about 62 light-years away from our system, but 1.5 million years ago it approached less than a fifth of a light-year. That is 11,256 astronomical units, and the star is only half the mass of the Sun. The orbits of the planets were not affected, but they certainly disturbed the orbits of comets and asteroids on the fringes of the solar system.