Some Greate AstronomersHipparchus
Hipparachus of Nicaea was a Greek astronomer who lived in second century BC. And died in 127 BC.
The frame work for astronomy was created by Hipparchus.His idea were almost lost until they were rescued by the Greek astronomer Ptolemy. They were developed into a system that lasted 1,500 years until they were overthrown by the ideas of Copernicus. Ancient Babylonian records brought back by Alexander the great from his conquest helped Hipparchus make his observation of the stars.
Hipparchus was the first to try to measure earth’s distance to the sun. The first star catalog, listing 850 stars, was put together by hipparchus.Hipparchus was also the first to identify constellations systematically and to assess stars in terms of magnitude. He discovered that the position of the stars on the equinoxes slowly shift around, taking 26000 years to return to their original place.this is the “precession of the equinoxes”.
KeplerThe German astronomer Johannes Kepler (1571-1630) discovered the basic rules about the way in which the planets move.kepler got his ideas by studying the movements of mars. Before Kepler’s discoveries it was thought that the planets moved in the circle.kepler discovered that the true shape of the planets orbit is elliptical. This is Kepler’s first law.
Kepler’s second law is that the speed of a planet through space varies according to its distance from the sun. A planet moves fastest when its orbit brings it nearest to the sun (its perihelion). It moves slowest when it is farthest from the sun (its aphelion).the third law is that a planet’s period, the time it takes to complete its yearly orbit of the sun depends on its distance from the sun.
Kepler’s third law states that the square of a planet’s period is proportional to the cube of its average distance from the sun. He also believed that the planets made music as they moved, and called this “the music of the sphere”.
HerschelWilliam Herschel (1739-1822) was a German musician who became the king’s astronomer in England and built his own powerful telescope. Until Herschel’s time astronomers thought that there were only five planets in addition to earth orbiting the sun. The five known planets at that time were mercury, Venus, mars, Jupiter and Saturn. Uranus, the sixth planet was discovered by William Herschel in 1781.
At first, Herschel thought that the dot of light he could see through his telescope was a nebula or comet. When he looked again four days later, it had moved against the background of stars, so it must be in the solar system. He realized that it was a new planet. He wanted to name the planet George after King George III, but Uranus was eventually chosen, after the ancient Greek God of the sky.
His sister Caroline was his partner in his discoveries. She was a great astronomer who discovered eight comets and produced catalogs of stars and nebulae. His son John cataloged the stars of the southern hemisphere. Herschel himself added to the catalog of nebulae. he later
HubbleEdwin Hubble (1889-1953) was an American who trained in law at the universities of Chicago and oxford and was also a great boxer before he turned to astronomy. Until the early 20th century, astronomer thought that the milky way galaxy was all there was in the universe. In the 1920’s, Hubble showed that the fuzzy patches of light once thought to be nebulae were in fact other galaxies far beyond the milky way.
In 1929, Hubble measured the distance of 20 galaxies and showed that they were all moving away from the earth. Resift showed Hubble that the farther away a galaxy is, the faster is it moving. The ratio of a galaxy’s distance to the speed it is moving away from earth is now known as Hubble’s law. Hubble’s law showed that the universe is getting bigger and so must have been smaller at one point.
Hubble’s constant is a measurement of the rate at which the universe is expanding. In the 1930’s, Hubble showed that the universe is isotropic (the same in all direction). The Hubble space telescope is named after Edwin Hubble.
Hipparachus of Nicaea was a Greek astronomer who lived in second century BC. And died in 127 BC.
The frame work for astronomy was created by Hipparchus.His idea were almost lost until they were rescued by the Greek astronomer Ptolemy. They were developed into a system that lasted 1,500 years until they were overthrown by the ideas of Copernicus. Ancient Babylonian records brought back by Alexander the great from his conquest helped Hipparchus make his observation of the stars.
Hipparchus was the first to try to measure earth’s distance to the sun. The first star catalog, listing 850 stars, was put together by hipparchus.Hipparchus was also the first to identify constellations systematically and to assess stars in terms of magnitude. He discovered that the position of the stars on the equinoxes slowly shift around, taking 26000 years to return to their original place.this is the “precession of the equinoxes”.
KeplerThe German astronomer Johannes Kepler (1571-1630) discovered the basic rules about the way in which the planets move.kepler got his ideas by studying the movements of mars. Before Kepler’s discoveries it was thought that the planets moved in the circle.kepler discovered that the true shape of the planets orbit is elliptical. This is Kepler’s first law.
Kepler’s second law is that the speed of a planet through space varies according to its distance from the sun. A planet moves fastest when its orbit brings it nearest to the sun (its perihelion). It moves slowest when it is farthest from the sun (its aphelion).the third law is that a planet’s period, the time it takes to complete its yearly orbit of the sun depends on its distance from the sun.
Kepler’s third law states that the square of a planet’s period is proportional to the cube of its average distance from the sun. He also believed that the planets made music as they moved, and called this “the music of the sphere”.
HerschelWilliam Herschel (1739-1822) was a German musician who became the king’s astronomer in England and built his own powerful telescope. Until Herschel’s time astronomers thought that there were only five planets in addition to earth orbiting the sun. The five known planets at that time were mercury, Venus, mars, Jupiter and Saturn. Uranus, the sixth planet was discovered by William Herschel in 1781.
At first, Herschel thought that the dot of light he could see through his telescope was a nebula or comet. When he looked again four days later, it had moved against the background of stars, so it must be in the solar system. He realized that it was a new planet. He wanted to name the planet George after King George III, but Uranus was eventually chosen, after the ancient Greek God of the sky.
His sister Caroline was his partner in his discoveries. She was a great astronomer who discovered eight comets and produced catalogs of stars and nebulae. His son John cataloged the stars of the southern hemisphere. Herschel himself added to the catalog of nebulae. he later
HubbleEdwin Hubble (1889-1953) was an American who trained in law at the universities of Chicago and oxford and was also a great boxer before he turned to astronomy. Until the early 20th century, astronomer thought that the milky way galaxy was all there was in the universe. In the 1920’s, Hubble showed that the fuzzy patches of light once thought to be nebulae were in fact other galaxies far beyond the milky way.
In 1929, Hubble measured the distance of 20 galaxies and showed that they were all moving away from the earth. Resift showed Hubble that the farther away a galaxy is, the faster is it moving. The ratio of a galaxy’s distance to the speed it is moving away from earth is now known as Hubble’s law. Hubble’s law showed that the universe is getting bigger and so must have been smaller at one point.
Hubble’s constant is a measurement of the rate at which the universe is expanding. In the 1930’s, Hubble showed that the universe is isotropic (the same in all direction). The Hubble space telescope is named after Edwin Hubble.
