GCSE›Edexcel GCSE Physics›Mind mapsThe Solar System & Lifecycles of StarsEdexcel GCSE Physics: Mind mapStudy pack PDFAlso for this subtopic:Revision notesFlashcardsSubtopic testCover factsWhat's in itSun at the centre, plus eight planetsAlso moons, dwarf planets, asteroids, cometsPlanets from Sun: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, NeptuneGeocentric model replaced by heliocentricOrbitsGravity gives the centripetal forceSpeed constant, direction changesSo velocity is changingFaster orbital speed → larger radiusggg depends on mass and radius of the bodyStars like the SunNebula: cloud of dust and gasMain sequence: fuses hydrogen into heliumRed giant: expands and coolsWhite dwarf: small, dense, hot remnantGravity and thermal expansion balanced → stableSolar Systemand life of starsgN/kgMassive starsNebula → main sequence → red supergiantCore collapses in a supernovaRemnant: neutron star or black holeShorter lifetime, fuse fuel fasterObservingTelescopes detect radio, infrared, UV, X-ray, gammaSpace telescopes avoid atmosphere absorptionAtmosphere also distorts visible lightExam tipsOrbiting planet: not constant velocitySpace telescope: say atmosphere absorbs or distorts