Teoria de la relatividad

1. 長 岡 技 術 科 学 大 学
NAGAOKA UNIVERSITY OF TECHNOLOGY
Advanced Engineering on Electromagnetic Energy
Herrera-Salazar María Guadalupe del Rocío (Student ID 14506181)
Maxwell's equations allow us to see clearly that electricity and magnetism are two
manifestations of the same physical phenomenon, electromagnetism. A body moving electrically
charged produces an electromagnetic force on another charged body. The most important
difference is that the magnitude and direction of the electromagnetic force depend of the load of
the body that produce and also its speed. Maxwell's equations describe the behavior of the
electromagnetic field at each point in space and at each time point (three spatial coordinates x,
y, z, and time t). Also can change the position and time in Maxwell's equations without altering
its shape, Lorentz showed that there is a mathematical transformation that leaves invariant the
form of Maxwell's equations, provided that not only the position is changed but also the time.
In 1905 Einstein postulated that the Maxwell equations must have the same form in
any inertial reference system and therefore, it is impossible distinguish from electromagnetic
experiments an inertial reference system of another. For that the principle of relativity is met, it is
necessary that the Lorentz transformations are physically valid; accordingly, the time measured
between two events depends on the movement of who measured. Einstein postulated that there
is not absolute time, neither absolute space, so time doesn't elapses of the same form for
different observers. Is important to note that the effect predicted by Einstein is only noticeable at
speeds approaching that of light.
Thus Einstein said that the speed of light in vacuum is a fundamental constant of
nature, regardless of who the measure, this speed is extremely high compared to our everyday
experience. Einstein realized also that the mass and energy of a body always appear together
in a very remarkable manner, as shown in the following equation:
𝐸 = 𝑚𝑐2
(1)
Where 𝐸 is the energy of a body, 𝑚 its mass and 𝑐2
is the speed of light squared.
Einstein's formula states that in one kilogram of matter is roughly equivalent to all the energy
consumed in the earth in one hour.
According to the basic principle of the theory of relativity, physical phenomena obey
laws that do not depend on the frame of reference of which observe. Actually, a perfect inertial
reference system must be isolated in outer space, far from whatever body that can to attract it
gravitationally.
The essence of Einstein's theory is that the mass of a body warps the space-time
around them. In the absence of mass, space-time is flat and a particle is moving in a straight
line because nothing affects his career, but in the presence of a gravitating mass, space-time is
curved and a particle moves along a geodesic.
In Einstein's theory, the curvature of space-time is calculated, but the situation is quite
complicated because not only the mass but also the energy exerts a gravitational action. In
1916, Einstein published his mathematical equation that relates the geometry of space-time with
the distribution of mass and energy, this formula is known as Einstein equation and is the basis
of general relativity. The mathematical equations of general relativity (2) permit to calculate the
curvature of space-time produced by a given mass as well as the trajectories of the particles
under the influence of the mass.
(2)