Category Scientist & Invensions

Who was the last man to discover a planet?

Clyde Tombaugh, a young American research student, made the last discovery of a planet while working in 1930 at the Lowell Observatory, Arizona state College. This planet is Pluto, the ninth one in order of distance from the sun, 3,670 million miles away.

    Although Tombaugh, who was 26 at the time, was the first astronomer to see Pluto, its existence had been suspected by Percival Lowell, builder of the observatory at Flagstaff, Arizona. Lowell began searching for the planet in 1905, the year before Tombaugh was born. He observed that there was a difference between the predicted and actual positions of Uranus, and this led him to conclude that there must be another planet. His final calculations about “panel X” were published in 1914, but he had still not found the planet when he died two years later.

    Another American, W.H Pickering, took up the search, concentrating on the irregular movements of the planet Neptune. He saw a clue in the movement of comets, which seem to be attracted by large planets. Here were 16 known comets whose paths took them millions of miles beyond Neptune. Which is 2,800 million miles from the sun, and Pickering was convinced that they were being attracted by a still more distant planet.

   In 1919 yet another hunt was begun by Milton Humason at Mount Wilson Observatory, Pasadena, California. Instead of mathematical calculation, Humason tried photograph. He took two pictures of a series of stretches of the sky, with a gap of one or two days between exposures. In such photographs stars stay still, but planets change position.

    When Tombaugh discovered Pluto, it became clear that Humason had photographed the planet twice. Once it had been masked by a star, and the second time its image had coincided with a flaw in the photographic plate. The main difficulty in the search had been that Pluto was extraordinarily faint. Pickering formed the opinion that it was not Lowell’s planet X, but that a huge planet remains to be discovered.

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When was the hydrofoil invented?

The hydrofoil, a boat supported clear of the water by underwater wings called hydrofoils, was invented by an Italian, Forlanini, in 1898. In 1918 a hydrofoil, powered by an aircraft engine, gained the world’s water speed record. The commercial hydrofoils now used in Europe are based on the work of German engineers who carried out research into the design of high-power, lightweight engines.

       In the early 1950s hydrofoils were developed in the United States, Canada and Russia using high-powered gas turbines. They are used for both military and commercial purposes.

     Since water is 775 times heavier than air, very small hydrofoil wings will support relatively heavy boats. But, since operating in water puts great loads on boats, the hulls are usually built of high-strength steel.

    The object in raising the hull of the hydrofoil from the water is to avoid the resistance caused by friction and drag. This means the power needed to drive the boat at high speeds is cut by half. Another result is that the hydrofoil travels smoothly in quite rough water, and is not slowed down.

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Who invented the jet engine?

The first flight by a jet-propelled aircraft was made in Germany on August 27, 1939. Its engine was designed by Hans-Joachim von Ohain, who had conceived the idea while a student at Gottingen University in Lower Saxony. Unknown to von Ohain, the British inventor and aviator Frank Whittle had thought of the idea some years earlier. But his engine did not have its first flight until May 14, 1941.

    Briefly, a jet engine takes in air from the atmosphere, compresses it, and uses it in burning fuel. The mixture of hot gases is then expelled through a nozzle in a powerful backward jet which propels the aircraft forwards.

     This forward thrust is the effect of a scientific principle first explained by the English scientist Sir Isaac Newton (1642-1727). He pointed out that with every action there is a reaction which is equal but opposite to it. Thus when a gun is fired, the forward movement of the shell is matched by the backward recoil of the barrel. In a similar way the reaction to the jet exhaust drives the engine forward. The thrust is obtained by the pressure of the jet against the inside of the nozzle and not, as many people suppose, by the exhaust gases “pushing” against the atmosphere.

     The jet engine, whether turbojet, turboprop, ramjet or turbofan, weights less than a piston engine of comparative power and can be much more streamlined.

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When was the telephone invented?

Alexander Graham Bell (1847-1922) invented and patented in 1876 the first telephone that was of any real practical use. In 1874 he said: “if I could make a current of electricity vary in intensity precisely as the air varies in density during the production of sound, I should be able to transmit speech telegraphically.” This is the principle of the telephone.

      On March 10, 1872, the first historic message was telephoned to Thomas A Watson, Bell’s assistant, who was in another room: “Mr. Watson, come here; I want you.”

     Bell’s first machine gave electrical currents too feeble to be of much use for the general public. In 1877 the American scientist Thomas A. Edison (1847-931) invented the variable-contact carbon transmitter, which greatly increased the power of the signals.

    The telephone was immediately popular in the United States, but Bell found little interest in Britain when he visited the country in 1878. Then Queen Victoria asked for a pair of telephone and the royal interest resulted in a London telephone exchange being formed in 1879 with eight subscribers.

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When was the sextant invented?

            The sextant was invented in England in 1732 by John Hadley. Hadley’s instrument is used mainly at sea to determine a ship’s latitude, or distance from the equator. Its invention laid the foundation of modern navigation with the aid of the sun and stars.

              The instrument is so called because it is equipped with an arc which is usually one-sixth of a circle, or 600. It measures the angle of the sun’s or a star’s altitude above the horizon. As this angle varies with the distance from the equator, the information obtained helps the navigator to calculate his position. All he needs in addition is the time, the date and the longitude which can be found by comparing local time with the time at Greenwich.

         To operate the sextant, the navigator looks through its small telescope straight at the horizon. At the same time, an image of the sun is reflected by mirrors into the user’s field of vision. When the sun is made to appear exactly on the horizon, the arm which moves the mirrors gives the required measurements to calculate the ship’s position.

       The handling of a sextant is generally to as “shooting the sun”.

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Who first classified butterflies and moths?

            Butterflies and moths were first classified by the great Swedish botanist Carl von Linne (1707-78), generally known as Carolus Linnaeus. His method, which applied to plants and all living things, was the binomial system. This meant the each insect was given two scientific and internationally recognized names: the first is a generic name denoting the genus or group to which the subject belongs; the second is a specific epithet indicating the species within the group.

            Similarly we all have surnames and forenames. But, in the case of the Linnaean system, Latin or Greek words are used to ensure uniformity regardless of the expert‘s native language. The first or generic name is spelt with a capital letter, but the second name usually begins with a small one.

               Linnaeus published more than 180 scientific works, some of the most important ones after he left Sweden for Holland, where he studied medicine. After visiting England and France he returned to Sweden, where he was given the chair of botany at Uppsala University.