c, or the speed of
light, is the speed of which photons travel in a vacuum, A.K.A. the fastest speed in the
universe.
To travel at/exceed this speed would result in breaking the fabric of space-
time.
c = 299,792,458 meters per second = 671,000,000 miles per hour
The
new spaceship, Exr-C2 can travel at 0.6 * c (
light-speed), or 60% of the speed of
light.