9 ms·

Interestingly, the database contains two other objects detected with impact speeds of more than 40km/s including one from 2015-07-04 which an even greater speed

by spuz 5y ago

Interestingly, the database contains two other objects detected with impact speeds of more than 40km/s including one from 2015-07-04 which an even greater speed than this interstellar asteroid. I wonder why these are not also considered to have interstellar origin? Is it because they were accelerated by the sun before colliding with the Earth? The original paper does not mention whether or not they considered the origins of any other objects from the database. https://cneos.jpl.nasa.gov/fireballs/ https://cneos.jpl.nasa.gov/fireballs/

sandworm101 5y ago
Direction of travel can make a big difference. If it impacts one side of the earth, the leading side in the earths orbit around the sun, then you need to subtract the earth's orbital velocity. On the opposite side, you need to add earth's velocity to get a true representation of the object's speed around the sun. The earth is also spinning. The atmosphere is moving at basically the same speed as earth's rotation. That too has to be accommodated based on the direction and latitude of the impact. Lastly, something that this paper doesn't address. There is a chance that the object was local to our solar system but had been 'flung' out onto an escape trajectory. Our solar system is a giant multi-body problem. Things can be flung out into space. This rock might have been accelerated to escape velocity by our moon or some other body. So rather than an interstellar object, it may have been a local rock on its way out that just happened to hit earth before leaving the solar system.
- spuz 5y ago
  Good point about the relative speed of the earth. That could probably explain why the other objects turn out to be more ordinary. As for the idea that this 2014 object originated in our solar system: I don't think that's possible. They were able to project it's incoming trajectory and there were no significant masses that could have directed it path from anywhere other than interstellar space. This is pretty clear from the paper.

by spuz 5y ago

sandworm101 5y ago

Direction of travel can make a big difference. If it impacts one side of the earth, the leading side in the earths orbit around the sun, then you need to subtract the earth's orbital velocity. On the opposite side, you need to add earth's velocity to get a true representation of the object's speed around the sun. The earth is also spinning. The atmosphere is moving at basically the same speed as earth's rotation. That too has to be accommodated based on the direction and latitude of the impact. Lastly, something that this paper doesn't address. There is a chance that the object was local to our solar system but had been 'flung' out onto an escape trajectory. Our solar system is a giant multi-body problem. Things can be flung out into space. This rock might have been accelerated to escape velocity by our moon or some other body. So rather than an interstellar object, it may have been a local rock on its way out that just happened to hit earth before leaving the solar system.

spuz 5y ago
Good point about the relative speed of the earth. That could probably explain why the other objects turn out to be more ordinary. As for the idea that this 2014 object originated in our solar system: I don't think that's possible. They were able to project it's incoming trajectory and there were no significant masses that could have directed it path from anywhere other than interstellar space. This is pretty clear from the paper.