
James Clerk Maxwell
(1831 - 1879) |
James Clerk Maxwell is generally regarded as the
greatest theoretical physicist of the 19th century. Born in
Edinburgh to a well-known Scottish family, he entered the University of
Edinburgh at age 15, around the time that he discovered an original
method for drawing a perfect oval. Maxwell was appointed to his
first professorship in 1856 at Aberdeen. This was the beginning
of a career during which he would develop the electromagnetic
theory of light and explanations of the nature of Saturn's rings, and
contribute to the kinetic theory of gases.
Maxwell's development of the electromagnetic theory of
light took many years and began with the paper "On Faraday's Lines
of Force," in which Maxwell expanded upon Faraday's theory that the
electric and magnetic effects result from force fields surrounding
conductors and magnets. His next publication, "On Physical
Lines of Force," includes a series of papers explaining the known
effects and the nature of electromagnetism.
Maxwell's other important contributions to theoretical
physics were made in the area of the kinetic theory of gases.
Here, he furthered the work of Rudolf Clausius, who in 1858 had shown
that a gas must consist of molecules in constant motion colliding with
one another and with the walls of the container. This resulted in
Maxwell's distribution of molecular speeds in addition to important
applications of the theory of viscosity, conduction of heat, and
diffusion of gases.
Maxwell's successful interpretation of Faraday's
concept of the electromagnetic field resulted in the field equation
bearing Maxwell's name. Formidable mathematical ability
combined with great insight enabled Maxwell to lead the way in the
study of the two most important areas of physics at his
time. Maxwell died of cancer before he was 50.
Maxwell's contributions to
electromagnetic theory were honored by naming a mountain on Venus
for him.
This is a simulated airplane view of Maxwell
Montes (65°N, 5°E). With topography, radar imagery, and a lot of
imagination, it is possible to create the view an airplane pilot
might see approaching Maxwell Montes from the northwest at an
altitude of 7 kilometers. The SAR imagery has been false-colored
and overlaid on the topography rendered as a three-dimensional
surface (no vertical exaggeration). The simulated clouds and haze
add to the perception of depth and distance in the image. [From
David P. Anderson (Southern Methodist University).]
Source: http://cass.jsc.nasa.gov/images/sven/sven_s15.gif |
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Heinrich Hertz
(1857 - 1894) |
Heinrich Rudolf Hertz was born in 1857 in Hamburg,
Germany. He studied physics under Helmholtz and Kirchoff at
the University of Berlin. In 1885, Hertz accepted the
position of Professor of Physics at Karlsruhe; it was here that he
demonstrated radio waves in 1887, his most important accomplishment.
In 1889 Hertz succeeded Rudolf Clausius as Professor
of Physics at the University of Bonn. Hertz's subsequent
experiments involving metal penetration by cathode rays led him to the
conclusion that cathode rays are waves rather than
particles. Exploring radio waves, demonstrating their
generations, and determining their speed are among Hertz's many
achievements. After finding that the speed of a radio wave was the
same as that of light, Hertz showed that radio waves, like light waves,
could be reflected, refracted, and diffracted.
Hertz died of blood poisoning at the age of 36.
During his short life, he made many contributions to science. The
hertz, equal to one complete vibration or cycle per second, is named
after him. |