# First object from another solar system

**URL:** <https://boards.straightdope.com/t/first-object-from-another-solar-system/800014>\
**Category:** Miscellaneous and Personal Stuff I Must Share\
**Created:** [October 27, 2017, 7:55pm UTC](https://boards.straightdope.com/t/first-object-from-another-solar-system/800014 "2017-10-27T19:55:28Z")\
**Posts on this page:** 1\
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**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\
**Post date:** [October 27, 2017, 9:24pm UTC](https://boards.straightdope.com/t/first-object-from-another-solar-system/800014/10 "2017-10-27T21:24:28Z")

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> [@TriPolar](#):
>
> They seem surprised we haven’t identified one before (see quote), but then again our ability to spot such a thing is a recent development.

Playing around with numbers a bit–[the estimate is](https://en.wikipedia.org/wiki/Interstellar_comet) that there are between 1 trillion and 10 trillion interstellar comets per cubic parsec. One cubic parsec is 2.72x10[sup]17[/sup] cubic astronomical units. So the chance of any interstellar comet to randomly be within one AU of the Earth is from 1 in 272,000 to 1 in 27,200.

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