ppt1.1_chapter1_lesson1(2)_solar system.pdf

Solar System  Solar System Our solar system is the system of planets and other object that orbit our sun. There are eight planets asteroids, comets, and tiny particles of rocks and dust. The sun, a star, is the largest object in the solar system and holds everything in place by its gra...

Solar System  Solar System Our solar system is the system of planets and other object that orbit our sun. There are eight planets asteroids, comets, and tiny particles of rocks and dust. The sun, a star, is the largest object in the solar system and holds everything in place by its gravity. It contains about 99% of the mass of the solar system.  Planet A planet is a large, rounded astronomical body that is neither a star nor its remnant. The best available theory of planet formation is the nebular hypothesis The nebular hypothesis is the most widely accepted model in the field of cosmogony to explain the formation and evolution of the Solar System (as well as other planetary systems). It suggests the Solar System is formed from gas and dust orbiting the Sun which clumped up together to form the planets. The theory was developed by Immanuel Kant and published in his Universal Natural History and Theory of the Heavens (1755) and then modified in 1796 by Pierre Laplace. Planet in order closest to the sun Mercury From the surface of Mercury, the Sun would appear more than three times as large as it does when viewed from Earth, and the sunlight would be as much as 11 times brighter. Venus is the second planet from the Sun. It is a rocky planet with the densest atmosphere of all the rocky bodies in the Solar System, and the only one with a mass and size that is close to that of its orbital neighbor Earth. In addition to being extremely hot, Venus is unusual because it spins in the opposite direction of Earth and most other planets. It also has a very slow rotation making its day longer than its year. Earth is the only planet in our galaxy that can support life. Scientists estimate that Earth is home to about 300,000 plant species, over 600,000 species of fungi, and about ten million animal species. Unlike the other planets in the Solar System, The name Earth derives from the eighth century Anglo-Saxon word erda, which means ground or soil, and ultimately descends from Proto- Indo European Mars is the fourth planet from the Sun – a dusty, cold, desert world with a very thin atmosphere. Mars is also a dynamic planet with seasons, polar ice caps, canyons, extinct volcanoes, and evidence that it was even more active in the past. Mars does have an atmosphere, but it is about 100 times thinner than Earth's atmosphere and it has very little oxygen. The atmosphere on Mars is made up of mainly carbon dioxide. Jupiter is the fifth planet from the Sun and the largest in the Solar System. It is a gas giant with a mass more than two and a half times that of all the other planets in the Solar System combined, and slightly less than one one-thousandth the mass of the Sun. Saturn is the sixth planet from the Sun and the second- largest in the Solar System, after Jupiter. It is a gas giant with an average radius of about nine and a half times that of Earth. It has only one- eighth the average density of Earth, but is over 95 times more massive. Uranus is the seventh planet from the Sun and is a gaseous cyan ice giant. Most of the planet is made out of water, ammonia, and methane in a supercritical phase of matter, which in astronomy is called 'ice' or volatiles. Rotates at a nearly 90-degree angle from the plane of its orbit. This unique tilt makes Uranus appear to spin on its side. Neptune is one of two ice giants in the outer solar system (the other is Uranus). Most (80% or more) of the planet's mass is made up of a hot dense fluid of "icy" materials – water, methane, and ammonia – above a small, rocky core. Of the giant planets, Neptune is the densest. Pluto is a dwarf planet that lies in the Kuiper Belt, an area full of icy bodies and other dwarf planets out past Neptune. Pluto is very small, only about half the width of the United States and its biggest moon Charon is about half the size of Pluto. Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radiation, and is the most important source of energy for life on Earth. The Sun holds the solar system together, keeping everything – from the biggest planets to the smallest debris Our Moon is like a desert with plains, mountains, and valleys. It also has many craters, holes created when space rocks hit the surface at a high speed. There is no air to breathe on the Moon. The Moon travels around the Earth in an oval- shaped orbit. Phases of the Moon A star is an astronomical object comprising a luminous spheroid of plasma held together by self-gravity. The nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night; their immense distances from Earth make them appear as fixed points of light. A constellation is an area on the celestial sphere in which a group of visible stars forms a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The origins of the earliest constellations likely go back to prehistory.