836
xkcd #3084: Unstoppable Force and Immovable Object
(imgs.xkcd.com)
Title text:
Unstoppable force-carrying particles can't interact with immovable matter by definition.
Transcript:
[An arrow pointing to the right and a trapezoid are labeled as 'Unstoppable Force' and 'Immovable Object' respectively.]
[The arrow is shown as entering the trapezoid from the left and the part of it in said trapezoid is coloured gray.]
[The arrow is shown as leaving the trapezoid to the right and is coloured black.]
[Caption below the panel:] I don't see why people find this scenario to be tricky.
Source: https://xkcd.com/3084/
Neutrinos are pretty close to an unstoppable force: they can pass right through the earth without being stopped.
I believe this is an expectation of dark matter, to being even closer to an unstoppable force. Perhaps a reason we haven’t found it yet would a because we don’t have a detector that can stop it