Gravity

Apparently, Newton's laws are not standing up to the numbers observed as Spaceship Voyager heads out of the solar system. Instead of Dark Energy (hitherto unobserved forces), my brother proposes negative gravity (I think).
I appreciate gravity. I enjoyed my brainy relatives definition of it as a weak force, allowing us to stay connected to our places on this world yet giving the freedom to move, defining our struggles, shaping our dance.