The ideas and discoveries about Earth

Hipparchus 190 – 120 BC Claudius Ptolemy 85 – 165 AD Nicolas Copernicus 1473 – 1543 Tycho Brahe 1546 – 1601 Johannes Kepler 1571 – 1630 Galileo Galilei 1564 – 1642 Edwin Hubble 1889 – 1953 Sir Isaac Newton 1642 – 1727 Edmund Halley 1656 – 1742 Sir William Herschel 1738 – 1822 Caroline Herschel 1750 – 1848 Albert Einstein 1879 – 1955

Timeline of Ideas Ptolemy He suggests the idea of epicycles to suggest how planets move. The Earth is still at the centre of the Solar System. (approx. 150 BC) Galileo Made major advances in telescope design. (1594 AD) Johannes Kepler He suggests three laws of planetary motion and that orbits are ellipses and not circles. (1600 AD) Edwin Hubble Discovered that the universe is expanding. (1929 AD) 1000 BC 2000 AD Aristotle He suggests that the Earth is at the centre of the solar system. (approx. 340 BC) Aristarchus He suggests the idea of the Sun at the centre of the Solar System. (approx. 200 BC) Nicolas Copernicus Suggests that the sun is at the centre of the Solar System. (1543 AD) Isaac Newton Suggested the idea of planetary gravity. (1700 AD) William Herschel Discovered Uranus (1781 AD)

Galileo Galilei Galileo Galilei was an Italian scientist, mathematician, astronomer and philosopher He improved the telescope and consequent astronomical observations. He was named the ‘father of modern observational astronomy’, ‘father of physics’, ‘father of science’ and ‘father of modern science’.

Galileo Galilei (cont.) Galileo was able to use this telescope to prove the truth of the Copernican system of heliocentrism. He published his observations which went against the teaching of the Church. He was brought to trial and was imprisoned for life. Other scientists seized its importance and could learn more the world. He was the first person to identify Sunspots and to see the 4 brightest moons of Jupiter. He also noticed that our view of Venus changes in the same way as that of our Moon.

Copernicus Nicolaus Copernicus was a Renaissance mathematician and astronomer. He came up with the heliocentric system where the Sun was at the center in 1508. Earlier starwatchers had believed the same, but he brought it to the world of and used his own observations to back up his idea. His ideas, including the revelation that the Earth rotates on its axis, were too different for most of the scholars of his time to accept. In 1512, he recorded a basic sketch of his system in a manuscript called Commentariolus

Isaac Newton Sir Isaac Newton was an English physicist, mathematician, astronomer, natural philosopher, alchemist and theologian. He had described universal gravitation and the three laws of motion He built the first practical reflecting telescope

Henrietta Swan Leavitt Henrietta Swan Leavitt was an American astronomer. Leavitt discovered the relation between the luminosity and the period of Cepheid variable stars. Her discovery allowed astronomers to measure the distance between the Earth and faraway galaxies. Edwin Hubble used the luminosity-period relation for Cepheids to determine that the Universe is expanding.

Subrahmanyan Chandrasekhar Subrahmanyan Chandrasekhar, was an Indian-American astrophysicist. He won the 1983 Nobel Prize for Physics for key discoveries that led to the currently accepted theory on the later evolutionary stages of massive stars. Chandrasekhar worked in various areas including stellar structure, theory of white dwarfs, stellar dynamics, theory of radiative transfer, quantum theory of the negative ion of Hydrogen, hydrodynamic and hydromagnetic stability, equilibrium and the stability of ellipsoidal figures of equilibrium, general relativity, mathematical theory of black holes and theory of colliding gravitational waves.

Stephen Hawking Stephen William Hawking, is a theoretical physicist, cosmologist, and author. His significant scientific works are gravitational singularities theorems and the theoretical prediction that black holes emit radiation, often called Hawking radiation. He thinks that we may be able to leave earth, aliens exist and that time travel is possible. Hawking has achieved success with works of popular science in which he discusses his own theories and cosmology in general; his A Brief History of Time stayed on the British Sunday Times best-sellers list for a record- breaking 237 weeks. He is almost entirely paralysed and communicates through a speech generating device.

Professor Michael Robinson and Dr Brian May They modelled the space dust in the solar system. It explains the infrared radiation from zodiacal dust seen

Quiz! Who was Galilio Galilei? What is Nicolas Copernicus famous for? What did Isaac Newton invent? Edwin Hubble used the theory of which scientist to determine that the Universe is expanding? Who was Subrahmanyan Chandrasekhar? What did Stephen Hawking predict? What did Professor Michael Robinson and Dr Brian May do?