The discovery of other large objects in the Kuiper belt, particularly Eris, spurred debate about how exactly to define a planet. With the development of the telescope, the meaning of planet broadened to include objects only visible with assistance: the ice giants Uranus and Neptune Ceres and other bodies later recognized to be part of the asteroid belt and Pluto, later found to be the largest member of the collection of icy bodies known as the Kuiper belt. Earth itself was recognized as a planet when heliocentrism supplanted geocentrism during the 16th and 17th centuries. Planets have historically had religious associations: multiple cultures identified celestial bodies with gods, and these connections with mythology and folklore persist in the schemes for naming newly discovered Solar System bodies. ![]() In antiquity, this word referred to the Sun, Moon, and five points of light visible by the naked eye that moved across the background of the stars-namely, Mercury, Venus, Mars, Jupiter and Saturn. The word planet probably comes from the Greek planḗtai, meaning "wanderers". The giant planets bear planetary rings, the most prominent being those of Saturn. Apart from Venus and Mars, the Solar System planets generate magnetic fields, and all except Venus and Mercury have natural satellites. All planets of the Solar System other than Mercury possess a considerable atmosphere, and some share such features as ice caps, seasons, volcanism, hurricanes, tectonics, and even hydrology. These planets each rotate around an axis tilted with respect to its orbital pole. ![]() The Solar System has at least eight planets: the terrestrial planets Mercury, Venus, Earth and Mars, and the giant planets Jupiter, Saturn, Uranus and Neptune. ![]() Planets grow in this disk by the gradual accumulation of material driven by gravity, a process called accretion. The best available theory of planet formation is the nebular hypothesis, which posits that an interstellar cloud collapses out of a nebula to create a young protostar orbited by a protoplanetary disk. Sizes are not to scale.Ī planet is a large, rounded astronomical body that is neither a star nor its remnant. Shown in order from the Sun and in true color. Jupiter and Saturn ( gas giants) Uranus and Neptune ( ice giants) The eight known planets of the Solar System, according to the IAU definition: For other uses, see Planet (disambiguation). Most astronomers in the 18th and 19th centuries thought of them as unresolved star clusters or anagalactic nebulae, and simply thought of them as a part of the Milky Way, but their true structure and natures were unknown.This article is about the astronomical object. Spiral nebulae were the first galaxies to be observed by telescope. It was borrowed from French and Medieval Latin. The word galaxy comes from the Greek word galaxas, which refers to the Milky Way's presence as a milky band of light in the sky. Thus the order is ‘Universe, galaxies, solar system, star, earth, moon, and asteroid ‘. In the world there are billions of galaxies in it. Clusters of galaxies are large-scale systems formed by galaxies. A supermassive black hole is found at the centre of almost all galaxies. It is considerably larger than a star.Ī cosmos, like our own Milky Way Galaxy, is made up of solar systems sharing a central centre. Our Sun is a massive star that dwarfs all of the planets together.Ī star and all of the planets, asteroids, comets, and other bodies make up a solar system. Planets surround the sun, which is referred to as a star. ![]() Such moons are also bigger than some asteroids.Ī planet is a nearly spherical body that orbits the Sun in a nearly spherical orbit. Some moons, such as our own, are very huge, even exceeding the size of an asteroid. In most cases, a moon is a rocky body which orbits around a sun. Ceres, the largest asteroid, has been reclassified as a dwarf planet. In truth, there are several exceptions to the size order.Īsteroid is a rocky body that orbits between Mars and Jupiter in the asteroid belt. Universe, galaxies, solar system, star, earth, moon, and asteroid are listed in order of size from largest to smallest.Įxplanation: Let's describe them one by one, from smallest to biggest. Iii) Galaxies vary in size from dwarfs with a few hundred million (108) stars to giants with one hundred trillion (1014) stars, all sharing their galaxy's mass core. Ii) The word galaxy comes from the Greek galaxias, which means "milky" and refers to the Milky Way galaxy. I) A galaxy is a gravitationally bound system of stars, stellar remnants, interstellar gas, dust, and dark matter that consists of stars, stellar remnants, interstellar gas, dust, and dark matter.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |