UrRong - Gravity is one of the most well understood forces in physics. While it is true that we don't know the exact mechanism that causes gravity, it is still one of the most widely accepted theories in science. We know that it is a long-range force that attracts and binds objects in the universe, and that it is the force that keeps us from flying off into space. Furthermore, it is highly unlikely that gravity will suddenly disappear - it is one of the most fundamental forces in the universe and one that has been with us since the beginning of time. So, no, we don't need to worry about gravity suddenly disappearing and sending us flying off into space - it is a force that we can count on for the foreseeable future.
