What if there was no force of gravity?
Picture a barren wasteland. According to James Overduin, a physicist at Towson University in Maryland who specializes in gravitation, a universe without gravity would be “completely flat and featureless.” Overduin explained that gravity is just another term for the curvature of space-time — how steep or shallow the fabric of the universe is in a given place (and thus how likely objects are to fall toward the source of curvature). Just as a bowling ball placed on a trampoline curves its surface, it is the presence of matter and energy that cause space-time to curve. So, if the universe can’t curve (because gravity doesn’t exist), then there can be no matter or energy within it.
“This would be a boring universe,” Overduin told Life’s Little Mysteries, a sister site to LiveScience.