Work against gravity.
Angels travel at the speed of light.
Highest speed in free-fall.
Causes the sky to appear blue.
All matter is in pairs.
Smallest particle is a string.
Carries God's name in Arabic.
Most of the electromagnetic spectrum is invisible.
Time slows in gravity/acceleration.
Angels use wormholes for transportation.
Curvature of spacetime.
Mass curves spacetime.
Copper used in armor-piercing.
Ripples in spacetime.
Sound waves can incapacitate or kill.
Determined by the vibration of strings.
Mass in extra dimensions.
Acceleration is equivalent to gravity.
Expansion of universe stretches light waves.