![]() ![]() The sun’s mass is more than 333,000 times that of Earth, and contains about 99.8 percent of all of the mass in the entire solar system! Composition The sun is made up of a blazing combination of gases. The sun not only has a much larger radius than Earth-it is also much more massive. ![]() That distance is about 109 times the size of Earth’s radius. The radius of the sun, or the distance from the very center to the outer limits, is about 700,000 kilometers (432,000 miles). It takes light about eight minutes and 19 seconds to reach Earth from the sun. An AU can be measured at light speed, or the time it takes for a photon of light to travel from the sun to Earth. This distance, called an astronomical unit (AU), is a standard measure of distance for astronomers and astrophysicists. The sun is about 150 million kilometers (93 million miles) from Earth. Other parts of the molecular cloud cooled into a disc around the brand-new sun and became planets, asteroids, comets, and other bodies in our solar system. Eventually, the gases heated up enough to begin nuclear fusion, and became the sun in our solar system. Much of the hydrogen and helium remained in the center of this hot, rotating mass. As one of these regions collapsed, it also began to rotate and heat up from increasing pressure. The molecular cloud began to compress, and some regions of gas collapsed under their own gravitational pull. A nearby supernova emitted a shockwave, which came in contact with the molecular cloud and energized it. About 4.5 billion years ago, the sun began to take shape from a molecular cloud that was mainly composed of hydrogen and helium. ![]() Without the sun’s heat and light, life on Earth would not exist. The sun has extremely important influences on our planet: It drives weather, ocean currents, seasons, and climate, and makes plant life possible through photosynthesis. Animated explanation of the temperature of the Photosphere (University of South Wales).The sun is an ordinary star, one of about 100 billion in our galaxy, the Milky Way.Animated explanation of the Photosphere (University of South Wales).Media related to Photosphere at Wikimedia Commons."SP-402 A New Sun: The Solar Results From Skylab". Monthly Notices of the Royal Astronomical Society. "Heterogeneity of solid neutron-star matter: Transport coefficients and neutrino emissivity". "Nature of Fault Planes in Solid Neutron Star Matter". "Whole Earth Telescope observations of BPM 37093: A seismological test of crystallization theory in white dwarfs". All heavier elements, called metals in astronomy, account for less than 2% of the mass, with oxygen (roughly 1% of the Sun's mass), carbon (0.3%), neon (0.2%), and iron (0.2%) being the most abundant. The Sun is composed primarily of the chemical elements hydrogen and helium they account for 74.9% and 23.8%, respectively, of the mass of the Sun in the photosphere. Therefore, the photosphere is typically used to describe the Sun's or another star's visual surface. Stars, except neutron stars, have no solid or liquid surface. The surface of a star is defined to have a temperature given by the effective temperature in the Stefan–Boltzmann law. It extends into a star's surface until the plasma becomes opaque, equivalent to an optical depth of approximately 2⁄ 3, or equivalently, a depth from which 50% of light will escape without being scattered.Ī photosphere is the deepest region of a luminous object, usually a star, that is transparent to photons of certain wavelengths. The term itself is derived from Ancient Greek roots, φῶς, φωτός/ phos, photos meaning "light" and σφαῖρα/ sphaira meaning "sphere", in reference to it being a spherical surface that is perceived to emit light. ![]() The photosphere is a star's outer shell from which light is radiated. ![]()
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