4 ms·

Understanding there's orders of magnitude of possible scale, what's the likelihood that one of these passing through the solar system would destabilize it enoug

by jcims 5y ago

Understanding there's orders of magnitude of possible scale, what's the likelihood that one of these passing through the solar system would destabilize it enough to affect Earth? What happens if it hits the sun?

vimacs2 5y ago
Very low but a more common and likely possibility is that it could disturb the oort cloud and cause comets to fall in system. Guess that could classify as what you are referring to depending on your definition of solar system. A passing star is more likely to do this though and we believe that they indeed have caused disturbances in our oort cloud in the past. They might be potentially less numerous than rogue planets as our universe ages but they have a far larger potential hill sphere than even a very large planet so interactions with neighboring stars' hill spheres are more likely and frequent.
- adolph 5y ago
  I've normally seen "oort" capitalized, so here is some background if others have the same question as me. The Oort cloud (/ɔːrt, ʊərt/),[1] sometimes called the Öpik–Oort cloud,[2] first described in 1950 by Dutch astronomer Jan Oort,[3] is a theoretical[4] concept of a cloud of predominantly icy planetesimals proposed to surround the Sun at distances ranging from 2,000 to 200,000 au (0.03 to 3.2 light-years).[note 1][5] It is divided into two regions: a disc-shaped inner Oort cloud (or Hills cloud) and a spherical outer Oort cloud. Both regions lie beyond the heliosphere and in interstellar space.[5][6] The Kuiper belt and the scattered disc, the other two reservoirs of trans-Neptunian objects, are less than one thousandth as far from the Sun as the Oort cloud. https://en.wikipedia.org/wiki/Oort_cloud https://en.wikipedia.org/wiki/Oort_cloud
  - alistairSH 5y ago
    It was not very long ago that I realized the outer bounds of our Oort cloud are actually closer to Alpha Centauri (4.25 light years away) than the sun. The scale of the universe never ceases to elicit feelings of existential dread.
    - actually_a_dog 5y ago
      The outer edges of the cloud seem to be at ~100K AU [0], while the α Centauri system is ~268K AU from us [1]. NASA also gives the same number [2] for the distance to the edge of the cloud. So, it looks like the Cloud extends almost halfway to α Centauri, but not that it's "closer to α Centauri than us"). As for the scale of the Universe: https://htwins.net/scale2/ https://htwins.net/scale2/ --- [0]: https://en.wikipedia.org/wiki/Oort_cloud#/media/File:PIA17046_-_Voyager_1_Goes_Interstellar.jpg https://en.wikipedia.org/wiki/Oort_cloud#/media/File:PIA1704... [1]: https://imagine.gsfc.nasa.gov/features/cosmic/nearest_star_info.html https://imagine.gsfc.nasa.gov/features/cosmic/nearest_star_i... [2]: https://solarsystem.nasa.gov/solar-system/oort-cloud/overview/ https://solarsystem.nasa.gov/solar-system/oort-cloud/overvie...
      - alistairSH 5y ago
        Huh, the first paragraph of that same wikipedia says the cloud extends to 2000 AU. Either way, whenever I try to think about these things, I feel mild anxiety. Why am I here? What's the point of all this? I'M SO TINY! Aaaahhhhhhhhh! I probably need to lay off the sci-fi novels for a while.
- actually_a_dog 5y ago
  This sounds reasonable to me, assuming Mercury didn't either fall into the Sun or hit Venus. However, from the perspective of Earth, we might not notice this much, due to the effect of Jupiter (usually) either flinging comets away from us, or actually absorbing the impact of the comets.
actually_a_dog 5y ago
Ejection of the gas giants doesn't even take place until after the Sun has gone into its red giant phase. The Sun will swell so much that it engulfs the inner planets (Mercury, Venus, Earth, Mars), so, Earth won't even be around to become destabilized. Interestingly, the paper I linked talks about Mercury having a 1% chance of becoming unstable before the Sun enters its red giant phase: > The mechanism forthe onset of Mercury’s instability is well understood: by virtue of locking into a linear secular resonance with theg5mode of the solar system’s secular solution, Mercury’s eccentricity can attain near-unity values, resulting in a collision with the Sun, or even Venus. Intriguingly, General Relativistic effects factor into this estimate, with ancillary apsidal precession providing a stabilizing influence on Mercury’s orbit. If Mercury collides with the Sun, not much interesting will happen. Mercury doesn't have enough mass to disrupt the center of gravity of the Solar System when it falls into the Sun, so, all that will happen is that the planet will get vaporized, and the Sun will become infinitesimally more enriched in metals. If you were around to witness the event, it might be visually spectacular, but not particularly significant with respect to the fate of the system itself. They go on to say: > Within the context of this narrative, however, the remaining planets appear unaffected and are currently expected to remain stable for a lower limit of 10^18 years, when diffusion arising from the overlapping mean motion resonance of Jupiter and Saturn are expected to decouple Uranus. This analysis, however, is reflective of older studies, which don't take into account certain factors that this paper does.
- kjs3 5y ago
  If Mercury collides with the Sun, not much interesting will happen. Yeah...but if it hits Venus......

by jcims 5y ago

vimacs2 5y ago

Very low but a more common and likely possibility is that it could disturb the oort cloud and cause comets to fall in system. Guess that could classify as what you are referring to depending on your definition of solar system. A passing star is more likely to do this though and we believe that they indeed have caused disturbances in our oort cloud in the past. They might be potentially less numerous than rogue planets as our universe ages but they have a far larger potential hill sphere than even a very large planet so interactions with neighboring stars' hill spheres are more likely and frequent.

adolph 5y ago
I've normally seen "oort" capitalized, so here is some background if others have the same question as me. The Oort cloud (/ɔːrt, ʊərt/),[1] sometimes called the Öpik–Oort cloud,[2] first described in 1950 by Dutch astronomer Jan Oort,[3] is a theoretical[4] concept of a cloud of predominantly icy planetesimals proposed to surround the Sun at distances ranging from 2,000 to 200,000 au (0.03 to 3.2 light-years).[note 1][5] It is divided into two regions: a disc-shaped inner Oort cloud (or Hills cloud) and a spherical outer Oort cloud. Both regions lie beyond the heliosphere and in interstellar space.[5][6] The Kuiper belt and the scattered disc, the other two reservoirs of trans-Neptunian objects, are less than one thousandth as far from the Sun as the Oort cloud. https://en.wikipedia.org/wiki/Oort_cloud https://en.wikipedia.org/wiki/Oort_cloud
- alistairSH 5y ago
  It was not very long ago that I realized the outer bounds of our Oort cloud are actually closer to Alpha Centauri (4.25 light years away) than the sun. The scale of the universe never ceases to elicit feelings of existential dread.
  - actually_a_dog 5y ago
    The outer edges of the cloud seem to be at ~100K AU [0], while the α Centauri system is ~268K AU from us [1]. NASA also gives the same number [2] for the distance to the edge of the cloud. So, it looks like the Cloud extends almost halfway to α Centauri, but not that it's "closer to α Centauri than us"). As for the scale of the Universe: https://htwins.net/scale2/ https://htwins.net/scale2/ --- [0]: https://en.wikipedia.org/wiki/Oort_cloud#/media/File:PIA17046_-_Voyager_1_Goes_Interstellar.jpg https://en.wikipedia.org/wiki/Oort_cloud#/media/File:PIA1704... [1]: https://imagine.gsfc.nasa.gov/features/cosmic/nearest_star_info.html https://imagine.gsfc.nasa.gov/features/cosmic/nearest_star_i... [2]: https://solarsystem.nasa.gov/solar-system/oort-cloud/overview/ https://solarsystem.nasa.gov/solar-system/oort-cloud/overvie...
    - alistairSH 5y ago
      Huh, the first paragraph of that same wikipedia says the cloud extends to 2000 AU. Either way, whenever I try to think about these things, I feel mild anxiety. Why am I here? What's the point of all this? I'M SO TINY! Aaaahhhhhhhhh! I probably need to lay off the sci-fi novels for a while.
actually_a_dog 5y ago
This sounds reasonable to me, assuming Mercury didn't either fall into the Sun or hit Venus. However, from the perspective of Earth, we might not notice this much, due to the effect of Jupiter (usually) either flinging comets away from us, or actually absorbing the impact of the comets.

actually_a_dog 5y ago

Ejection of the gas giants doesn't even take place until after the Sun has gone into its red giant phase. The Sun will swell so much that it engulfs the inner planets (Mercury, Venus, Earth, Mars), so, Earth won't even be around to become destabilized. Interestingly, the paper I linked talks about Mercury having a 1% chance of becoming unstable before the Sun enters its red giant phase: > The mechanism forthe onset of Mercury’s instability is well understood: by virtue of locking into a linear secular resonance with theg5mode of the solar system’s secular solution, Mercury’s eccentricity can attain near-unity values, resulting in a collision with the Sun, or even Venus. Intriguingly, General Relativistic effects factor into this estimate, with ancillary apsidal precession providing a stabilizing influence on Mercury’s orbit. If Mercury collides with the Sun, not much interesting will happen. Mercury doesn't have enough mass to disrupt the center of gravity of the Solar System when it falls into the Sun, so, all that will happen is that the planet will get vaporized, and the Sun will become infinitesimally more enriched in metals. If you were around to witness the event, it might be visually spectacular, but not particularly significant with respect to the fate of the system itself. They go on to say: > Within the context of this narrative, however, the remaining planets appear unaffected and are currently expected to remain stable for a lower limit of 10^18 years, when diffusion arising from the overlapping mean motion resonance of Jupiter and Saturn are expected to decouple Uranus. This analysis, however, is reflective of older studies, which don't take into account certain factors that this paper does.

kjs3 5y ago
If Mercury collides with the Sun, not much interesting will happen. Yeah...but if it hits Venus......