Solar System PDF

Solar system Formed in 4.6 billion years A galaxy is defined as gravitationally-bound system of stars, stellars remnants, Interstellar gas, and dark matter. Solar nebular: The solar nebular hypothesis describes the formation of our solar system from a nebula cloud made from a collection of dust...

Solar system Formed in 4.6 billion years A galaxy is defined as gravitationally-bound system of stars, stellars remnants, Interstellar gas, and dark matter. Solar nebular: The solar nebular hypothesis describes the formation of our solar system from a nebula cloud made from a collection of dust and gas. It is believed that the sun, planets, moons, and asteroids were formed around the same time around 4.5 billion years ago from a nebula. Nebulae- the remaining gas and dust cloud form disk-shaped bodies. Protoplanet: The protoplanet hypothesis suggests that a great cloud of gas and dust of at least 10,000 million kilometers in diameter rotated slowly in space about 5,000 million years ago. As time passed, the cloud shrank under the pull of its own gravitation or was made to collapse by the explosion of a passing star. Asteroids: are made up of rocks and are sometimes referred to as minor planets in many ways. The asteroid belt, where most asteroids in the solar system lies, is located in between the orbit of mars and Jupiter. First known asteroids: Ceres Comets: composed mainly of ice (frozen water and gas). Kupiter belt is often called the solar systems “final frontier” because of the outermost region of the solar system. Trans-Neptunian objects: objects orbiting beyond Neptune. Inner planets or also known as Terrestrial planets: The planets Mercury, Venus, Earth, and Mars, are called terrestrial because they have a compact, rocky surface like Earth’s terra firma. The terrestrial planets are the four innermost planets in the solar system. None of the terrestrial planets have rings, although Earth does have belts of trapped radiation, as discussed below. Among the terrestrials, only Earth has a substantial planetary magnetic field. Mars and the Earth's moon have localized regional magnetic fields at different places across their surfaces, but no global field Mercury, : Mercury lacks an atmosphere to speak of. Even though most of its surface is very hot, there is strong evidence that water ice exists in locations near its north and south poles which are kept permanently shaded by crater walls. This evidence comes from Earth-based radar observations of the innermost planet. The discovery of permanently-shaded ice at the poles of Earth’s moon strengthens arguments that the indications of ice on Mercury may be real. Venus, : atmosphere of carbon dioxide is dense, hot, and permanently cloudy, making the planet’s surface invisible. Its best surface studies have come from landers and imaging radar from orbiting spacecraft.Venus has been visited by more than 40 spacecraft. The Magellan mission used synthetic aperture radar imaging and altimetry to map its surface at high resolution from 1990 to 1994. The European Venus Express, launched in 2005, has been orbiting Venus since April 2006. Earth, Earth, as of October 2016, is still the only place known to harbor life. And life has flourished here since the planet was young. Our home planet is also unique in having large oceans of surface water, an oxygen-rich atmosphere, and shifting crustal sections floating on a hot mantle below, described by the theory of plate tectonics. Earth’s Moon orbits the planet once every 27.3 days at an average distance of about 384,400 km. The moon’s orbital distance is steadily increasing at the very slow rate of 38 meters per millennium. Its distance at this point in its history makes the moon appear in the sky to be about the same size as the Sun, subtending about half a degree. And Mars, Mars’ atmosphere, also carbon dioxide, is much thinner than Earth’s, but it sustains wispy clouds of water vapor. Mars has polar caps of carbon dioxide ice and water ice. The planet’s surface shows strong evidence for extensive water coverage in its distant past, as well as possible evidence for water flow in small springs during recent times. Outer planets or also known as Jovian planets: Jupiter, Saturn, Uranus, and Neptune are known as the Jovian (Jupiter-like) planets, because they are all gigantic compared with Earth, and they have a gaseous nature like Jupiter’s – mostly hydrogen, with some helium and trace gases and ices. The Jovian planets are thus referred to as the “gas giants” because gas is what they are mostly made of, although some or all of them probably have small solid cores. All have significant planetary magnetic fields, rings, and lots of satellites. Jupiter: Jupiter is more massive than all the other planets combined. It emits electromagnetic energy from charged atomic particles spiraling through its strong magnetic field. If this sizzling magnetosphere were visible to our eyes, Jupiter would appear larger then the full moon in Earth’s sky. The trapped radiation belts near Jupiter present a hazard to spacecraft as do Earth’s Van Allen belts, although the Jovian particle flux and distribution differ from Earth’s. Bringing a spacecraft close to Jupiter presents a hazard mostly from ionized particles. Spacecraft intended to fly close to Jupiter must be designed with radiation-hardened components and shielding. Spacecraft using Jupiter for gravity assist may also be exposed to a harsh radiation dose. Instruments not intended to operate at Jupiter must be protected by being powered off or by having detectors covered. Saturn : Saturn, the farthest planet easily visible to the unaided eye, is known for its extensive, complex system of rings, which are very impressive even in a small telescope. Using a small telescope one can also discern the planet’s oblateness, or flattening at the poles. Continued study of Saturn’s ring system can yield new understandings of orbital dynamics, applicable to any system of orbiting bodies, from newly forming solar systems to galaxies. Saturn’s moons Titan, Enceladus, Iapetus, and others have proven to be extraordinarily interesting. Uranus and Neptune: Uranus which rotates on its side, and Neptune are of similar size and color, although Neptune seems to have a more active atmosphere despite its much greater distance from the Sun. Both planets are composed primarily of rock and various ices. Their extensive atmospheres, which make up about 15 percent the mass of each planet, are composed of hydrogen with a little helium. Both Uranus and Neptune have a retinue of diverse and interesting moons. These two cold and distant planets have had but one visitor, the intrepid Voyager 2