Einstein has said that all of the consequences of special
relativity can be derived from examination of the Lorentz
transformations.
These transformations, and hence special relativity, lead to
different physical predictions than Newtonian mechanics1 when
relative velocities approach the speed of light. The
speed of light is so much larger than anything humans encounter that
some of the effects predicted by relativity are initially
counterintuitive:
 Time dilation – the time lapse
between two events is not invariant from one observer to
another, but is dependent on the relative speeds of the
observers' reference frames (e.g., the twin paradox which
concerns a twin who flies off in a spaceship traveling near the
speed of light and returns to discover that his or her twin
sibling has aged much more).
 Relativity of simultaneity – two
events happening in two different locations that occur
simultaneously in the reference frame of one inertial observer,
may occur nonsimultaneously in the reference frame of another
inertial observer (lack of absolute simultaneity).
 Lorentz contraction – the
dimensions (e.g., length) of an object as measured by one
observer may be smaller than the results of measurements of the
same object made by another observer (e.g., the ladder paradox
involves a long ladder traveling near the speed of light and
being contained within a smaller garage).
 Composition of velocities –
velocities (and speeds) do not simply, for example if a
rocket is moving at a missile at 2/3 of the speed of light relative to the rocket, the missile does
not exceed the speed of light relative to the observer. (In this
example, the observer would see the missile travel with a speed
of 12/13 the speed of light.)

Inertia and momentum – as an
object's speed approaches the speed of light from an observer's
point of view, its mass appears to increase thereby making it
more and more difficult to accelerate it from within the
observer's frame of reference.
 Equivalence of mass and energy, E = mc^{2}
– The energy content of an object at rest with mass m
equals mc^{2}. Conservation of energy implies
that in any reaction a decrease of the sum of the masses of
particles must be accompanied by an increase in kinetic energies
of the particles after the reaction. Similarly, the mass of an
object can be increased by taking in kinetic energies.

"Great spirits have often encountered
violent opposition from weak minds."
Albert Einstein
March 14, 1879–April 18, 1955) was a Germanborn SwissAmerican
theoretical physicist, philosopher and author who is widely regarded
as one of the most influential and best known scientists and
intellectuals of all time. He is often regarded as the father of
modern physics. He received the 1921 Nobel Prize in Physics "for his
services to Theoretical Physics, and especially for his discovery of
the law of the photoelectric effect.
His many contributions to physics include the special and general
theories of relativity, the founding of relativistic cosmology, the
first postNewtonian expansion, explaining the perihelion advance of
Mercury, prediction of the deflection of light by gravity and
gravitational lensing, the first fluctuation dissipation theorem
which explained the Brownian movement of molecules, the photon
theory and waveparticle duality, the quantum theory of atomic
motion in solids, the zeropoint energy concept, the semi classical
version of the Schrödinger equation, and the quantum theory of a
monatomic gas which predicted Bose–Einstein condensation.
Einstein published more than 300 scientific and over 150
nonscientific works.
Einstein additionally wrote and commentated prolifically on numerous
philosophical and political issues.
