Is it possible for a comet to hit the earth?

Comets may hit the earth. There are so many comets in the solar system that it is entirely possible to hit the earth. But people don't have to panic, because the possibility of such a collision is very small. According to calculation, the probability of the earth hitting a comet is quite low, and it may only happen once in hundreds of thousands or even millions of years. Nevertheless, astronomers still attach great importance to this problem. For example, the United States has a near-earth asteroid search program to monitor near-earth asteroids and comets to prevent them from colliding with the Earth. Modern science and technology are highly developed. Once a comet is found to collide with the earth, it can also launch a spacecraft and destroy it with a nuclear bomb in an attempt to change its orbit and avoid colliding with the earth.