Earth could become an exile: what would happen if a wandering star appeared in the solar system
We all know that our solar system is in perfect and almost unbreakable balance: all planets know their places in this cosmic tank and none of them would dare to simply leave their orbit. But we also know that the universe, or even our own Milky Way galaxy, is full of surprises. In particular, this can be said of wandering stars - luminaries that, for one reason or another, can be thrown out of their own galaxies and become cosmic outcasts.
The researchers published their paper on the arXiv preprint site, in which they determined what could happen to the solar system if a wandering star appeared at a distance of 100 AU from the Sun. Spoiler alert: the probability of the Earth's destruction is extremely low, but something more interesting could happen.
As scientists have explained, stars are usually gravitationally attached to their galaxies and move in harmony with the environment. But sometimes there are incidents that break this connection. For example, this can happen if a star gets too close to a supermassive black hole. In this case, the black hole can push it out into space, turning it into a rogue star.
The Earth, as you know, is firmly in its orbit and is unlikely to move out of it even when it would be a good idea to do so. The further evolution of the Sun will eventually lead to the fact that in a billion years it will become so bright that life on our planet will become impossible.
Scientists have calculated that in the same range of one billion years, there is a chance of about 1% for a meeting with a rogue star. According to the scientists, statistics show that flybys closer than 100 AU, which would greatly affect the orbits of the planets, occur only about once every 100 years in the current area of the galaxy.
So the scientists performed a simulation and added a rogue star to the solar system. Next, they varied the star's mass and velocity, which led to 12,000 simulations.
It turned out that with a 95% probability, if the star passes within 100 AU of the Sun, none of the planets will die.
According to their data, Mercury is the most vulnerable to such an intervention. Other simulations also suggest the possibility of a collision between the Earth and Venus, the ejection of the ice giants Uranus and Neptune from the solar system, the survival of only the Earth and Jupiter, or even only Jupiter. There is also an apocalyptic scenario in which all eight planets are ejected from the solar system.
But, as the scientists explained, the mere fact of survival does not mean that nothing will happen. There are chances that the planets will still be gravitationally bound to the Sun, but their orbits may be severely disrupted, and some of them may be pushed far into the Oort Cloud (a hypothetical region at the edge of the solar system).
The researchers also compiled a table with the ten most likely consequences of planet destruction.
- Mercury collides with the Sun (2.54% probability).
- Mars collides with the Sun (1.21%).
- Venus collides with another planet (1.17%).
- Uranus ejects (1.06%).
- Neptune ejects (0.81%).
- Mercury collides with another planet (0.80%).
- Earth collides with another planet (0.48%).
- Saturn ejects (0.32%).
- Mars collides with another planet (0.27%).
- The Earth collides with the Sun (0.24%).
Uranus and Neptune have the highest chances of being ejected, due to their distance from the Sun and, as a result, a weaker gravitational connection. Mercury, on the other hand, is the smallest planet in the system, so it is not surprising that it has the highest chances of colliding with the Sun.
As for the Earth, there are various options for how it will react to the appearance of a rogue star. A collision with other planets is extremely unlikely - only 0.48% probability. But the Earth can get into a worse mess - it can be pushed into the Oort Cloud, where long-term survival, according to scientists, is "not guaranteed at all."
There is also an even more exotic option, which is that a rogue star (if it is somewhat more massive than our Sun) not only destroys the entire structure of the solar system, but also takes the Earth captive with its gravitational pull and takes it on a space journey.
In this scenario, six planets crash into the Sun and the only survivor is Jupiter, whose survival is guaranteed by its colossal mass.
Scientists have also considered scenarios of a collision between the Moon and the Earth, or the capture of both the Earth and the Moon by a passing star, and even the destruction of all planets and their satellites. But the likelihood of all this happening is extremely low.
As for humans on the planet, if we still exist there, scientists warn that a change in the Earth's orbit will make it warmer or colder.
However, the Earth can survive as a rogue planet for about a million years, until its surface freezes. Or, if it is captured by a rogue star, it may become habitable in new conditions.
In the end, scientists conclude, the most likely outcome is that all eight planets will survive, albeit in orbits that are slightly different from those they are currently moving in.
Earlier, OBOZ.UA talked about what would happen to the Earth and the solar system if there was another intermediate planet between Mars and Jupiter.