Which of the following is an empirical question?
1) would martin luther king, jr. have been a good president?
2) what is the meaning of life?
3) was the civil war necessary?
4) is there life on other planets?

"Is there life on other planets?" is the one among the following choices given in the question that is an empirical question. The correct option among all the options that are given in the question is the fourth option or the last option or option "4". I hope that this is the answer that has come to your desired help.