¥Space-time warping:
"distance" in a given reference frame is a mixture of distance and
time from other reference frames.
¥Length contraction:
objects seen in moving reference frames appear to be shorter along their
direction of motion than the same object seen at rest (Lorentz-Fitzgerald contraction).
¥Time dilation:
time intervals seen in moving reference frames appear longer than the same
interval seen at rest.
¥Velocities are
relative: "velocity" is a function of the velocity of the
observer. Velocities add up in
such a way that no velocity exceeds the speed of light.
¥There is no frame of
reference in which light can appear to be at rest.