Today we celebrate the
birth of Albert Einstein, born on
this day in 1879.
Albert Einstein,
(born March 14, 1879, Ulm, Württemberg, Germany—died April 18, 1955, Princeton, New Jersey, U.S.), was a German-born physicist who developed the
special and general theories of relativity and won the Nobel Prize for Physics in 1921 for his explanation of the photoelectric effect. Einstein is
generally considered the most influential physicist of the 20th century.
In the 19th century
there were two pillars of physics: Newton’s laws of motion and Maxwell’s theory
of light. Einstein was alone in realizing that they were in contradiction and
that one of them must fall. Owing to Planck’s laudatory comments and to
experiments that gradually confirmed his theories, Einstein was invited to
lecture at international meetings, and he rose rapidly in the academic world.
He was offered a series of positions at increasingly prestigious institutions,
including the University of Zürich, the University of Prague, and
finally the University of Berlin, where he served as director of
the Kaiser Wilhelm Institute for Physics from 1913 to 1933.
In November 1915
Einstein finally completed the general theory of relativity, which he
considered to be his masterpiece. Einstein was convinced that general
relativity was correct because of its mathematical beauty and because it
accurately predicted the precession of the perihelion of Mercury’s orbit around the Sun. His theory also predicted a measurable deflection of light around the Sun. As a consequence, he even offered to
help fund an expedition to measure the deflection of starlight during an eclipse of the Sun.
In 1921 Einstein
began the first of several world tours, visiting the United States, England, Japan, and France. En route from Japan, he received word that he had received
the Nobel Prize for Physics, but for the photoelectric effect rather than for his relativity theories.
Einstein also
launched the new science of cosmology. His equations predicted that the universe is dynamic—expanding or contracting. This contradicted
the prevailing view that the universe was static, so he reluctantly introduced
a “cosmological term” to stabilize
his model of the universe. In 1929 astronomer Edwin Hubble found that the universe was indeed expanding, thereby
confirming Einstein’s earlier work.
In December 1932
Einstein decided to leave Germany forever (he would never go back), as it became obvious
to Einstein that his life was in danger. Einstein settled at the
newly formed Institute for Advanced Study at Princeton, New Jersey, which soon became a mecca for physicists from around the
world.
In some sense,
Einstein may have been too far ahead of his time. The strong force, a major piece of any unified field theory, was still a total mystery in Einstein’s lifetime. Only in
the 1970s and ’80s did physicists begin to unravel the secret of the strong
force with the quark model. Nevertheless, Einstein’s work continues to win
Nobel Prizes for succeeding physicists. In 1993 a Nobel Prize was awarded to the discoverers of gravitation waves, predicted by Einstein. In 1995 a Nobel Prize was awarded to
the discoverers of Bose-Einstein condensates (a new form
of matter that can occur at extremely low temperatures). Known black holes now number in the thousands. New generations of space satellites have continued to verify the cosmology of Einstein. And many leading physicists are trying to
finish Einstein’s ultimate dream of a “theory of everything.”
Obtained from: Encyclopaedia Britannica, https://www.britannica.com/biography/Albert-Einstein/Nazi-backlash-and-coming-to-America.
Pi (π) Day March 14, 2020
Founded in 1988 at
the Exploratorium, Pi (π) Day has become an international holiday, celebrated
live and online all around the world. The numbers in the date (3/14) match the
first three digits of the mathematical constant pi (π).
What is π, anyway?
Divide any circle’s circumference by its diameter; the answer (whether for a
pie plate or a planet) is always approximately 3.14, a number we represent with
the Greek letter π. Keep calculating π’s digits with more and more
accuracy—as mathematicians have been doing for 4,000 years—and you’ll discover
they go on literally forever, with no pattern.
Pi is most commonly
shown as being 3.14159 but this is just an approximate value. It's an
irrational number, and its decimal representation never ends.
The History of Pi
Mathematicians
and scientists have been trying to uncover the mystery of Pi for thousands of
years, dating back to Ancient Greece and Babylonian times.
According
to Britannica Encyclopedia, in 2,000 BCE Pi used to be known as 3.125. This was
because the Babylonians calculated the perimeter of a hexagon within a circle.
Moving onto the ancient Egyptians (1650 BCE), the mathematical ratio became
3.16045, as shown in the Rhind papyrus—a document that included mathematical
tables and problems.
Archimedes,
the Greek mathematician, devised a method—in 250 BCE—to obtain Pi to any
desired accuracy. According to Britannica, the mathematician "inscribed
and circumscribed regular polygons" about a circle to get the upper and
lower bounds, getting an average value of 3.1418. Archimedes also discovered
that the ratio of the area of a circle to the square of its radius is the same
constant.
The
symbol for Pi was devised by a British mathematician named William Jones in
1706 AD and was later popularized by the Swiss mathematician Leonhard Euler.
Today, it is used in various formulas of physics and engineering to describe
the motion of pendulums, the vibration of strings, and alternating electric
currents.
As
the first three numbers in Pi are 3.14, March 14 is known as National Pi Day.
(@Newsweek Magazine)
