by Chris Peterson » Fri Jun 30, 2023 4:41 am
shaileshs wrote: ↑Fri Jun 30, 2023 4:25 am
Wow.. never imagined there's so many with their paths around Sun that close (relatively) to each other and all planets. We have decent idea about none of the PHA's (ones we have discovered/identified so far) colliding with Earth in next 100 years, I wonder, what's the probability of them hitting other planets ? Do we expect any such even soon (in next 20 years)? Because I don't think we are going to use DART to avoid those collisions.. but in turn those collisions might affect us some way (rays, gravity, changing plane of rotation, change of rotational axis, new moons for some planets... etc etc etc..) so maybe it's better NASA uses DART to avoid even those collisions ?
Keep in mind that if this were to scale, those lines would be the thickness of an atom. The image makes the space look much, much more densely filled than it actually is!
UPDATE: okay, just for fun, I did a couple of calculations. The full size image, displayed on a modern screen (100 pixels/cm) should be understood to have the following scale: the asteroid tracks (assuming 100 m diameter asteroids) should be drawn with a width of 1 picometer, or about 1/100th the size of an atom. The Earth's path should be drawn with a width of 160 nm, the wavelength of near UV light. And, of course, while there's a bias for these objects to have orbits near the ecliptic plane, they still cover a wide range of inclinations, so we're not looking here at a plane, but at a thick volume of space projected onto a plane. If we shifted our view so we were not directly above the ecliptic, this would look quite different.
[quote=shaileshs post_id=331976 time=1688099139 user_id=143908]
Wow.. never imagined there's so many with their paths around Sun that close (relatively) to each other and all planets. We have decent idea about none of the PHA's (ones we have discovered/identified so far) colliding with Earth in next 100 years, I wonder, what's the probability of them hitting other planets ? Do we expect any such even soon (in next 20 years)? Because I don't think we are going to use DART to avoid those collisions.. but in turn those collisions might affect us some way (rays, gravity, changing plane of rotation, change of rotational axis, new moons for some planets... etc etc etc..) so maybe it's better NASA uses DART to avoid even those collisions ?
[/quote]
Keep in mind that if this were to scale, those lines would be the thickness of an atom. The image makes the space look much, much more densely filled than it actually is!
UPDATE: okay, just for fun, I did a couple of calculations. The full size image, displayed on a modern screen (100 pixels/cm) should be understood to have the following scale: the asteroid tracks (assuming 100 m diameter asteroids) should be drawn with a width of 1 picometer, or about 1/100th the size of an atom. The Earth's path should be drawn with a width of 160 nm, the wavelength of near UV light. And, of course, while there's a bias for these objects to have orbits near the ecliptic plane, they still cover a wide range of inclinations, so we're not looking here at a plane, but at a thick volume of space projected onto a plane. If we shifted our view so we were not directly above the ecliptic, this would look quite different.