THE UNIVERSE A work of Pietro Addis and Claudio Ndreka INDEX Big bang, the big bang cronology The dark matter Internal solar system External solar system The stars The life of the stars The formations and the dead The solar system planets The sun THE UNIVERSE The physical Universe is defined as all of space and time (collectively referred to as spacetime) and their contents. Electromagnetic planets, moons,stars, Intergalatic space radiation galaxies Physical laws Conservation law The Big Bang theory is the prevailing cosmological description of the development of the Universe 13.799±0.021 billion years ago. Subatomics particles to form the atoms. BIG BANG: THE UNIVERSE INFLATION THE BACKGROUND RADIATION atoms the nuclei (mostly electrons hydrogen) After about 379,000 years, the electrons and nuclei combined into atoms (mostly hydrogen); hence the radiation decoupled from matter and continued through space largely unimpeded. This relic radiation is known as the cosmic microwave background radiation THE DARK MATTER the total mass-energy of the universe contains: 4.9% ordinary matter and energy 26.8% dark matter 68.3% of an unknown form of energy known as dark energy 100 80 60 unknown form of energy 40 dark matter 20 ordinary matter 0 ordinary ordinary dark matter dark energy matter and matter energy THE SOLAR SYSTEM The Solar System is the gravitationally bound system comprising the Sun and the objects that orbit it, either directly or indirectly. Of the objects that orbit the Sun directly, the largest eight are the planets THE EVOLUTION OF THE SYSTEM THE COMPOSITION OF THE SYSTEM • The principal component of the Solar System are: • the Sun, contains 99.86% of the system's mass. • the giant planest, account for 99% of the remaining mass, with Jupiter and Saturn together comprising more than 90%. • the four terrestrial planets, the dwarf planets,moons, asteroids,and comets comprise less than 0.002% of the total mass. THE GRAPHIC % mass planets sun gas planets terrestrial planets PICTURE THE TYPE OF PLANETS TERRESTRIAL PLANETS All terrestrial planets in the Solar System have the same basic type of structure, such as a central metallic core, mostly iron, with a surrounding silicate mantle. Terrestrial planets can have canyons, craters, mountains, volcanoes, and other surface structures, depending on the presence of water and tectonic activity. Terrestrial planets have secondary atmosphere,generated through volcanism or comet impacts. super-Earths are defined by their masses, and the term does not imply temperatures, compositions, orbital properties, habitability, or environments. While sources generally agree on an upper bound of 10 Earth masses. THE TYPE OF TERRSTRIAL PLANETS Silicate planet : The standard type of terrestrial planet seen in the Solar System, made primarily of silicon-based rocky mantle with a metallic (iron) core. • Carbon planets (or "diamond planet") • A theoretical class of planets, composed of a metal core surrounded by primarily carbon-based minerals. They may be considered a type of terrestrial planet if the metal content dominates. The Solar System contains no carbon planets, but does have carbonaceus asteroids. Iron planets: A theoretical type of terrestrial planet that consists almost entirely of iron and therefore has a greater density and a smaller radius than other terrestrial planets. Mercury has a metallic core equal to 60–70% of its planetary mass. Iron planets are thought to form in the high-temperature regions close to a star, and if the protoplanetary disk is rich in iron. Coroless planets A theoretical type of terrestrial planet that consists of silicate rock but has no metallic core, is the opposite of an iron planet. Although the Solar System contains no coreless planets, chondrite asteroids and meteorites are common in the Solar System. Coreless planets are thought to form farther from the star where volatile oxidizing material is more common. GAS PLANETS A gas giant is a giant planet composed mainly of hydrogen and helium. Gas giants are sometimes known as failed stars because they contain the same basic elements as a star. Gas giants can, be divided into five distinct classes according to their modeled physical atmospheric properties ammonia water cloudless alkali-metal silicate clouds (I) clouds (II) (III) clouds (IV) clouds (V) CLASSIFICATION • Cold gas giants • A cold hydrogen-rich gas giant more massive than Jupiter but less than about 500 M⊕ (1.6 MJ) will only be slightly larger in volume than Jupiter. For masses above 500 M⊕, gravity will cause the planet to shrink. • Gas dwarf . A gas dwarf could be defined as a planet with a rocky core that has accumulated a thick envelope of hydrogen, helium and other volatiles, having as result a total radius between 1.7 and 3.9 Earth-radii. THE STARS A star is type of astronomical object consisting of a luminous spheroid of plasma held together by its own gravity. For at least a portion of its life, a star shines due to thermonuclear fusion of hydrogen into helium in its core THE LIFETIME OF THE STARS nomenclature Mass (sun=1) Evolution collapse Very low mass stars. 0.5 Red giants Helium white dwarfs Low mass stars 0.5 and 1.8–2.5 Red giants White dwarfplanetary As the Sun. nebula or novae Intermediate-mass 1.8–2.5 and 5–10 Red giants Supernovae and stars. neutron stars Massive stars . 7–10 Red giants Supernovae and (N x 10 x sun) black holes THE SUN The Sun is the star at the center of the Solar system. It is a nearly perfect sphere of hot plasma with internal convective motion that generates a magnetic field via a dynamo process . Its diameter is about 1.39 million kilometers. Consist in the 99.86% of the total mass of the Solar System. the Sun's mass consists: hydrogen (~73%); helium (~25%), oxygen, carbon , neon, and iron.(~2%) THE STARS: SUN STRUCTURE THE SUN: THE CORE The core of the Sun extends from the center to about 20–25% of the solar radius. It has a density of up to 150 g/cm (and a temperature of close to 15.7 million kelvins (K). The energy has been produced by nuclear fusion in the core region through a series of steps called the p-p chain (this process converts hydrogen into helium). THE SUN: THE TACHOCLINE The radiative zone and the convective zone are separated by a transition layer, the tachocline. This is a region where the sharp regime change between the uniform rotation of the radiative zone and the differential rotation of the convection zone results in a large shear between the two—a condition where successive horizontal layers slide past one another.Presently, it is hypothesized that a magnetic dynamo within this layer generates the Sun's magnetic field THE SUN: THE CONVECTION ZONE The Sun's convection zone extends from 0.7 solar radii (500,000 km) to near the surface. In this layer, the solar plasma is not dense enough or hot enough to transfer the heat energy of the interior outward via radiation. Instead, the density of the plasma is low enough to allow convective currents to develop and move the Sun's energy outward towards its surface. The thermal columns of the convection zone form an imprint on the surface of the Sun giving it a granular appearance called the solar granulation. THE SUN: THE PHOTOSPHERE The visible surface of the Sun, the photosphere, is the layer below which the Sun becomes opaque to visible light. Above the photosphere visible sunlight is free to propagate into space, and almost all of its energy escapes the Sun entirely. The change in opacity is due to the decreasing amount of H − ions , which absorb visible light easily. Conversely, the visible light we see is produced as electrons react with hydrogen atoms to produce H− ions. Because the upper part of the photosphere is cooler than the lower part, an image of the Sun appears brighter in the center than on the edge or limb of the solar disk, in a phenomenon known as limb darkening. THE SUN: THE ATMOSPHERE It is composed of four distinct parts: the chromosphere, the transition region, the corona and the heliosphere. The coolest layer of the Sun is a temperature minimum region extending to about 500 km above the photosphere, and has a temperature of about 4,100 K. This part of the Sun is cool enough to allow the existence of simple molecules such as carbon monoxide and water, which can be detected via their absorption spectra Above the chromosphere, in a thin (about 200 km) transition region, the temperature rises rapidly from around 20,000 K in the upper chromosphere to coronal temperatures closer to 1,000,000 K. it forms a kind of nimbus around chromospheric features such as spicules and filaments, and is in constant, chaotic motion. The transition region is not easily visible from Earth's surface, but is readily observable from space by instruments sensitive to the extreme ulteaviolet portion of the spectrum OUR OPINION We think the universe is just obscure for us and so we belive that the humans should discover all possible things in it. According to us it is important to study the universe because it is our home and so we must know it also because sometimes it could be dangerous and we have to know how to face it. SITOGRAPHY https://www.nasa.gov/feature/goddard/2016/understanding-the-magnetic-sun https://www.researchgate.net/figure/Illustration-of-the-thermonuclear-fusion-reaction-Two-nuclei-deuterium-and- tritium_fig3_279601354 https://www.universetoday.com/40631/parts-of-the-sun/ https://www.focus.it/scienza/spazio/le-dimensioni-in-scala-del-sistema-solare-e-dei-suoi-pianeti https://www.google.it/imgres?imgurl=https%3A%2F%2Fblogs.egu.eu%2Fdivisions%2Fps%2Ffiles%2F2016%2F06%2F640px-