Galileo Galilei was born on 15 February 1564 near Pisa, the son of a musician. He began to study medicine at the University of Pisa but changed to philosophy and mathematics. In 1589, he became professor of mathematics at Pisa. In 1592, he moved to become mathematics professor at the University of Padua, a position he held until 1610. During this time he worked on a variety of experiments, including the speed at which different objects fall, mechanics and pendulums.
In 1609, Galileo heard about the invention of the telescope in Holland. Without having seen an example, he constructed a superior version and made many astronomical discoveries. These included mountains and valleys on the surface of the moon, sunspots, the four largest moons of the planet Jupiter and the phases of the planet Venus. His work on astronomy made him famous and he was appointed court mathematician in Florence.
In 1614, Galileo was accused of heresy for his support of the Copernican theory that the sun was at the centre of the solar system. This was revolutionary at a time when most people believed the Earth was in this central position. In 1616, he was forbidden by the church from teaching or advocating these theories.
In 1632, he was again condemned for heresy after his book 'Dialogue Concerning the Two Chief World Systems' was published. This set out the arguments for and against the Copernican theory in the form of a discussion between two men. Galileo was summoned to appear before the Inquisition in Rome. He was convicted and sentenced to life imprisonment, later reduced to permanent house arrest at his villa in Arcetri, south of Florence. He was also forced to publicly withdraw his support for Copernican theory.
Although he was now going blind he continued to write. In 1638, his 'Discourses Concerning Two New Sciences' was published with Galileo's ideas on the laws of motion and the principles of mechanics. Galileo died in Arcetri on 8 January 1642.
Isaac Newton was born on 4 January 1643 in Woolsthorpe, Lincolnshire. His father was a prosperous farmer, who died three months before Newton was born. His mother remarried and Newton was left in the care of his grandparents. In 1661, he went to Cambridge University where he became interested in mathematics, optics, physics and astronomy. In October 1665, a plague epidemic forced the university to close and Newton returned to Woolsthorpe. The two years he spent there were an extremely fruitful time during which he began to think about gravity. He also devoted time to optics and mathematics, working out his ideas about 'fluxions' (calculus).
In 1667, Newton returned to Cambridge, where he became a fellow of Trinity College. Two years later he was appointed second Lucasian professor of mathematics. It was Newton's reflecting telescope, made in 1668, that finally brought him to the attention of the scientific community and in 1672 he was made a fellow of the Royal Society. From the mid-1660s, Newton conducted a series of experiments on the composition of light, discovering that white light is composed of the same system of colours that can be seen in a rainbow and establishing the modern study of optics (or the behaviour of light). In 1704, Newton published 'The Opticks' which dealt with light and colour. He also studied and published works on history, theology and alchemy.
In 1687, with the support of his friend the astronomer Edmond Halley, Newton published his single greatest work, the 'Philosophiae Naturalis Principia Mathematica' ('Mathematical Principles of Natural Philosophy'). This showed how a universal force, gravity, applied to all objects in all parts of the universe.
In 1689, Newton was elected member of parliament for Cambridge University (1689 - 1690 and 1701 - 1702). In 1696,Newton was appointed warden of the Royal Mint, settling in London. He took his duties at the Mint very seriously and campaigned against corruption and inefficiency within the organisation. In 1703, he was elected president of the Royal Society, an office he held until his death. He was knighted in 1705.
Newton was a difficult man, prone to depression and often involved in bitter arguments with other scientists, but by the early 1700s he was the dominant figure in British and European science. He died on 31 March 1727 and was buried in Westminster Abbey.
Albert Einstein was born at Ulm in Baden-Wurttemberg, Germany, on March 14, 1879, into a non-observant Jewish family. At age five, his father showed him a pocket compass, and Einstein realized that something in "empty" space acted upon the needle; he would later describe the experience as one of the most revelatory of his life.
Although considered a slow learner, possibly due to dyslexia, simply shyness or the significantly rare and unusual structure his brain (examined after his death), Einstein built models and mechanical devices for fun. Another, more recent, theory about his mental development is that he had Asperger's syndrome, a condition related to autism.
Einstein began to learn mathematics around age 12. In 1894, his family moved from Munich to Pavia, Italy (near Milan), and this same year Einstein wrote his first scientific work, The Investigation of the State of Aether in Magnetic Fields.) He continued his education at Aarau, Switzerland, and in 1896, he entered the Swiss Federal Polytechnic School in Zurich to be trained as a teacher in physics and mathematics. In 1901, he gained his diploma and acquired Swiss citizenship. Unable to find a teaching post, he accepted a position as technical assistant in the Swiss Patent Office, obtaining his doctor's degree in 1905.
In 1908, Einstein was appointed Privadozent in Berne. The next year, he became Professor Extraordinary in Zurich, and in 1911 Professor of Theoretical Physics at Prague, returning to Zurich in 1912 to fill a similar post. In 1914, he was appointed Director of the Kaiser Wilhelm Physical Institute and Professor in the University of Berlin. He became a German citizen in 1914 and remained in Berlin until 1933, when he renounced his citizenship for political reasons and emigrated to America to take the position of Professor of Theoretical Physics at Princeton. He became a U.S. citizen in 1940 and retired from his post in 1945.
In his early days in Berlin, Einstein postulated that they correct interpretation of the special theory of relativity must also furnish a theory of gravitation, and in 1916 he published his paper on the general theory of relativity. During this time, he also contributed to the problems of the theory of radiation and statistical mechanics. In the 1920s, he embarked on the construction of unified field theories, continuing to work on the probabilistic interpretation of quantum theory, and he persevered with this work in America. He won the Nobel prize in 1921 "for his services to Theoretical Physics, and especially for his discovery of the law of the photoelectric effect." He contributed to statistical mechanics by his development of the quantum theory of a monatomic gas, and he has also accomplished valuable work in connection with atomic transition probabilities and relativistic cosmology.
Einstein initially favored construction of the atomic bomb, in order to ensure that Hitler did not do so first, and even sent a letter, dated August 2, 1939, to President Roosevelt encouraging him to initiate a program to create a nuclear weapon. Roosevelt responded to this by setting up a committee for the investigation of using uranium as a weapon, which in a few years was superseded by the Manhattan Project.
After the war, however, Einstein lobbied for nuclear disarmament and a world government. Along with Albert Schweitzer and Bertrand Russell, he fought against nuclear tests and bombs. As his last public act, and just days before his death, he signed the Russell-Einstein Manifesto, which led to the Pugwash Conferences on Science and World Affairs.
Einstein's latter years were also spent searching for a unified field theory, for a universal force that would link gravitation with electromagnetic and subatomic forces, a problem on which no one to date has been entirely successful.
Einstein received honorary doctorate degrees in science, medicine and philosophy from many European and American universities. During the 1920s, he lectured in Europe, America and the Far East and was awarded Fellowships or Memberships to all of the leading scientific academies throughout the world. He gained numerous awards in recognition of his work, including the Copley Medal of the Royal Society of London in 1925, and the Franklin Medal of the Franklin Institute in 1935.
Einstein married Mileva Maric in 1903, and they had a daughter and two sons; the marriage was dissolved in 1919, and that same year he married his cousin Elsa Lowenthal, who died in 1936. Einstein died on April 18, 1955, in Princeton, New Jersey. Element 99 was named einsteinium (Es) in his honor.
Einstein's Theory of relativity is definitely one of those few theories in the history of physics, that changed the way we see things. It revolutionized the cosmology in such a way that many physicists who are struggling in their respective lines of research produced some shockingly interesting results.
Black holes is one such shocking yet interesting result....
So, what is a black hole?
Well, there are a lot of definitions, and in the simple possible way: A Black hole is a region in space-time with such an immense gravitational pull towards its center that even light cannot escape out of it.
How is Einstein's 'Theory of relativity' responsible for its formation?
Black hole is a subject where its formation is almost entirely based on theoretical evidences rather than physical evidences(strong). All these theoretical proofs are in fact been implied from the Theory of relativity. To get some idea about its formation and stuff, we must know the life cycle of a star as a prerequisite.
A star takes birth when large amount of nearby gaseous particles(mostly hydrogen) attract towards each other and get squeezed. In this process of contraction, particles collide with each other to produce large quantities of heat energy. This heat in fact is responsible for the star to shine brightly. The heat thus produced would be so immense that, the particles when they come closer will no longer collide but coalesce, and forms higher elements like helium, Lithium, Berilium...along with some amount of heat. Heat that got released in this process, creates high pressure between the particles and tries to drive them away, opposing the contraction process. The more the star tends to contract, the more will be the opposing pressure. At some stage there will be a perfect balance between the contraction(force) and expansion(force) helping the star to remain stable. The star thus remains stable for quiet a long period of time(million millions of years) till one of its forces gets weaker. Obviously, it can't be the gravitational force(contraction) that gets weaker. The pressure inside the star eventually gets weaker, and the denser particles that gets cooled drift towards the center of the star, re surging the contraction process. This process continues till it reaches a stage where, the contraction force gets even by the repulsions between subatomic particles(electrons, protons, and neutrons). The star thus remains stable again for the second time.
The star that gets balanced by the repulsions between 'electrons' is termed as a 'White dwarf' with a radius of about few thousand miles and with a density of about hundreds of tons per cubic inch. And the one that is supported by the repulsions between protons and neutrons was popularly named as 'Neutron star' with a radius of about ten miles(only) and density, hundreds of millions of tons per cubic inch.
This would be the final stage of every known and unknown star that exist in our known and unknown universe, if the subatomic particles could move with out any limit. But, according to Einstein's Theory of relativity, nothing can travel faster than light.
Here comes the interesting question: What if the star is so heavy that it requires the electron(or proton or neutron) to move faster than light--to balance the immense contraction(force)?
These kinds of movements or repulsions among the subatomic particles are impossible according to the Theory of relativity and hence the star ends up in a gravitational collapse, and forms an infinitely dense region, popularly called as a 'Singularity'. The star that gets vanished in to a 'singularity' still exerts the same, finite light trapping gravitational pull(can be more but not less) up to certain distance in space creating a 'Black hole' around it. The boundary of this 'Black hole', the 'Event horizon' is formed by the paths of light just managed to move around but can't escape.
Thus the whole Black hole formation was almost based on Einstein's 'Theory of relativity'.
What if the electrons under those special conditions(gravitational collapse) could move with out a speed limit--faster than light ?
There will be no 'Singularity', no 'Black hole' but will be a 'Black star' or 'Dark star' that still can trap light.
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To get some clear understanding about the uncertainty principle, first, we need to know the quantum hypothesis.
Max Planck suggested that light, X-rays, and some other waves could not be emitted at the arbitrary rate, but in the form of energy packets called quanta.
According to the quantum hypothesis, each quantum--packet-- has certain amount of energy that was greater the higher the frequency of the waves. That implies that at higher frequencies, the emission of even a single quantum would require more energy than that was available. Thus the radiation at high frequencies gets reduced.
In order to predict the future position and velocity of a particle, one has to be able to determine its present position and velocity accurately. The only way to do this is to shine light on the particle and this will indicate its position. To determine more precisely one needs to use light of short wavelength(high frequency). Now, by Planck's quantum hypothesis, one cannot use an arbitrarily small amount of light; one has to use at least one quantum and this quantum will disturb the particle and change its velocity in a way that cannot be predicted. The more accurate one tries to measure the position, the greater will be the disturbance ( as it needs high energy quanta ). In other words, the more accurate one try to measure the position of a particle, the less accurate will be the speed and vice verse This principle put an end to a notion(came from Newton's theory of gravity) that our universe is completely deterministic ( one can easily predict everything that would happen in the universe, if he knows its present state.) It is only possible for the one who could observe the present state of universe with out disturbing it.
Ptolemy proposed his Geocentric theory in the 2nd century A.D. What he did was just an elaboration of already existing idea that earth was in the center of universe, proposed by Aristotle, in to a complete cosmological model.
According to his theory, the earth stood at the center, surrounded by some eight spheres, the Moon, the Sun, the stars, and the five other planets known till the time: Mercury, Venus, Mars, Jupiter, and Saturn.
The first sphere supposedly carried Moon followed by Mercury, Venus, Sun, Mars, Jupiter, Saturn, and some fixed stars--eighth sphere--in the remaining seven spheres. The outer most sphere that is supposed to carry the so-called fixed stars, rotate across the sky; the stars thus remain fixed with respect to earth--according to him.
What about the region beyond the eighth sphere ?
He didn't explained that, as there is no way one can observe beyond stars--no telescope and no Galileo.
Does this theory provided a reasonably accurate system for predicting the positions of heavenly bodies in the sky ?
Yes, it was, but got one serious flaw: to predict the positions correctly, Ptolemy had to make an assumption that the moon followed a path that sometimes brought it twice as close to the earth as at other times. And that meant that the moon ought sometimes to appear twice as big as at other times!
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A star is formed when a large amount of gas (mostly hydrogen) starts to collapse in on itself due to its high gravitational attraction. As it contracts the atoms of the gas collide with each other more and more frequently and at greater and greater speeds--the gas heats up. Eventually, the gas will be so hot that when the hydrogen atoms collide they no longer bounce off each other, but instead coalesce to form helium. The heat thus released in this reaction, which is like a controlled hydrogen bomb explosion is what makes the star shine.
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The Kiss..
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“I got lost.. in the woods and the pour.. Wandering in the darkness.. I
searched for light holding the lantern of desire.. My bare feet cuddling
earth.. in...
