Hi Elizabeth,
To become a scientist you have to enjoy and do well in math and science and also be able to communicate through writing and speaking. You need to get a Ph.D. (Doctor of Philosophy) in a science field. This means that you need to do well in school, get into college, complete college with a degree in science and make sure to take math classes and writing classes, and then get into graduate school to get your Ph.D. In order to get a Ph.D., you have to pass some difficult tests and then do research (study) something about nature that no one else has done before. After you finish discovering something (often with the help of an advisor and other professors), then you have to write it up in a thesis (a book of your findings). And you often have to write your findings in a paper which other scientists review to make sure what you are doing makes sense and is new. This paper will be published in a scientific journal. After all this, then you look for a job as a scientists to continue to discover new things!!
I don't know about the meteor. Meteors hit the Earth all the time and they are called meteorites. I assume you are wondering about a big meteorite that may cause a lot of damage? There are a lot of people watching out for such meteroites. Hopefully we'll know well in advance and be able to do something about the big ones.
Laura