Viewing a single comment thread. View all comments

mfb- t1_jd21nrk wrote

Reply to comment by Theleachan in How do we know if a comet will hit earth? by VloeibaarHout

> And optical telescopes require astroids to pass in front of a light source ie sun

No they do not. Asteroids close to the Sun (as seen from Earth) are the worst possible observation condition. They are much easier to see if they are farther away from the Sun and we can measure their reflected sunlight at night (at the telescope site).

4