What does Dr. Star's equation mean?

In fact, the old doctor has already solved this equation. In this way, it is impossible for human beings to get rid of gravity, which means that human beings cannot enter the era of interstellar migration. In other words, mankind is hopeless. The old doctor only left half of the equation to deceive everyone, saying that he had not solved it yet, in fact, in order to let some people go to another world by spaceship to continue mankind.