Passing star could potentially alter Earth’s orbit
Recent computer simulations of the solar system have revealed potential threats from the gravitational pull of passing stars.
Scientists warn that such stars could cause the Earth to collide with another planet or, conversely, throw our planet too close to or too far from the sun, which would lead to the end of life on Earth.
The main culprit is Mercury. Astronomers have long noticed that its oval-shaped orbit can become even more elliptical under Jupiter’s gravitational wobbles. Passing stars make the problem worse, Nathan A. Kaib of the Planetary Science Institute in Iowa and Sean Raymond of the University of Bordeaux report in a paper published May 7 on arXiv.org.
Modeling shows that under certain conditions, Mercury’s orbit could become so unstable that it would collide with either the Sun or Venus. This could trigger a chain reaction that would cause Venus or Mars to collide with Earth, and Earth to collide with the Sun. Jupiter’s gravity could also eject Earth from the solar system.
Still, the likelihood of such a scenario remains extremely low. Over the next 5 billion years, which is most of the sun’s remaining lifespan, the risk of a catastrophe for Earth is just 0.2%.
That’s significantly higher than previous studies had suggested, which didn’t account for the long-term effects of passing stars.
The most dangerous stars for the solar system are those located less than 100 astronomical units from the Sun. The probability of their close approach in the next 5 billion years is about 5%. Slowly moving stars also pose a danger, since their gravitational influence can last longer.
Interestingly, new models suggest that Pluto, once thought to be a safer place than Earth, may be in a more vulnerable position. Pluto is in a 3:2 resonance with Neptune, which prevents it from colliding with that planet.
However, if passing stars upset this stability, Pluto could collide with the giant planets or be ejected from the solar system altogether. The probability of such an event occurring over the next 5 billion years is about 4%, which is 20 times higher than the risk to Earth.
Sources and References:
Advertising by Adpathway
