“As part of NASA’s Child Star program, a student asked NASA scientists a question so seemingly rudimentary that the assistance of a “literal” rocket scientist in answering it felt more than a little unnecessary. “What is gravity?” the student asked. Shockingly, the NASA scientists shrugged: NASA scientist 1: “We don’t really know: We can define what it is as a field of influence because we know how it operates in the universe.” NASA scientist 2: “Actually, some scientists think that it is made up of particles called gravitons which travel at the speed of light.” NASA scientist 1: “However, if we are to be honest, we do not know what gravity ‘is’ in any fundamental way—we only know how it behaves.”19”