Univers

UNIVERS SOLAR SYSTEM • Our solar system contains 9 planets. • The planets in this system are separated through group. • There are two group namely.1-terrestrial planet group and 2-gas giant planet group. • In terrestrial planet group-Mercury, Venus, Earth, Mars. • In gas giant group-Jupiter, Saturn, Uranus, Neptune. While Pluto is in its group ice group planet. THOUGHTS OF ASTROPHYSICIST *ARISTOTLE OF GREECE 384-322 B.C. During his lifetime the Greek philosopher Aristotle thinks and thinks. Finally he decided that earth is the centre of all existence and that the other heavenly bodies revolve around it in perfect circle. We must love this idea of geocentric (earth-centered) *Alexandria, Egypt, A.D. 127-145 Claudius Ptolemaeus, known as Ptolemy, refines Aristotle ideas but agrees that everything revolves around the earth. *Poland 1543 Astronomer Nicolas Copernicus developed a theory that earth and the other planet orbit the sun, that they are heliocentric (sun-centered). THE STAR INFO *MAIN PHASE The star remains 1-20million years in this phase. Stars more massive than the sun lives fast and die young. They burn their hydrogen fuel in less than 20 million years. Initially they are blue and shine much hotter and brighter than the sun. *RED SUPERGIANT The stars remain 2-5 million years in this stage. As a star runs out of hydrogen’ it begins to expand. Its core heats up while the outer layer cool and glow red. As its core, the red supergiant burns its helium to make other element, including carbon & oxygen. *SUPER NOVA Star glow brightly for only several months in this stage. Iron absorbs energy rather than releasing. The star collapse under its own mass, condensing its core into dense nucleus. There nucleus react by releasing massive shock wave. A super nova can shine brighter than 1 billion other suns. *NEUTRON STAR Star 10-30times massive than sun. the core that remains become a star made up of neutron, which are extraordinarily dense. A teaspoon full of neutron star material weighs about 10 billion pound. *BLACK HOLE It is 30-50 times more massive than sun. The core that remains after supernova is so massive that nothing can support it against its own gravity. It collapses into itself and become a black hole.