Transcript The Sun
The Sun Chapter 28 Basic Properties • Composition of sun 0.8% 28% 70% H He O C 0.3% Fe 0.2% Basic Properties • • • • • 332,000x mass then earth 695,000 km at equator 6,000°C average temp. Rotates 1 about every 30 days Age= ~5.0 billion years old Structure of the Sun • 3 Regions – Core – Inner Zone – Atmosphere The Core • • • • ~10% of the sun 15,000,000° C Made up of gas Because of gravity the core is 10x denser than iron The Core • Heat in the core causes electrons of the atoms to roam free • Exposed nuclei is then changed by nuclear reactions • Give a hydrogen fusion reaction Hydrogen Fusion • Step 1 – 2 hydrogen nuclei collide and fuse • Step 2 – One of these protons changes into a neutron • Step 3 – Another proton combines with the proton-neutron pair, producing a nucleus of 2 protons and 1 neutron • Step 4 – 2 of these nuclei collide and fuse • Step 5 – Resulting cluster throws off 2 protons, leaving behind a nuclei of 2 protons and 2 neutrons Hydrogen Fusion • Energy is given off in every step • Changes more then 600,000,000 of H into He every sec. Mass into Energy • 1905-Albert Einstein proposes the Theory of Relativity • Proposed this before nuclear physics • E=mc² • E represents energy produced, m represents mass, and c represents the speed of light The Inner Zones • 2 regions within this zone – Radiative Zone – Convective Zone Radiative Zone • Zone that surrounds core • 2,500,000°C • Energy moves from atom to atom in the form of electromagnetic waves, or radiation Convective Zone • Zone around radiative zone • About 1,000,000°C • Energy moves by convection • Hot gases rise, and cool gases sink Sun’s Atmosphere • • • • Uppermost region of solar gases Photosphere Chromosphere Corona Photosphere • Innermost layer of atmosphere • Surface of the sun-what we see ~6,000°C • Grainy appearance-Granulation – Caused by the rising and sinking of gases from the Convective zone Chromosphere • Chromosphere = Color sphere • Thin layer of gases that glows reddish light • Temp. ranges from 4,00050,000°C • Gases move away and towards the photosphere • May form narrow jets of gas that shoot outward Corona • Crown of the sun-Outermost layer • Huge cloud of gas heated by sun’s magnetic field ~2,000,000°C • Prevents most of the atomic particles from sun escaping into space • Atomic particles that escape cause solar wind Solar Activity • Gases in sun are in constant motion • Energy and gravity are main reason • Sun also rotates on its axis • Parts of the sun rotate at different speeds • Equator rotates faster than the poles – Equator ~25 days – Poles ~33 days • Average rotation is 27 days Sunspots • Magnetic fields slow down activity in convective zone • Slower convection means less gas transfers heat • This causes cooler areas on the surface called sunspots • Sunspots run in a 11 year cycle Prominences • As a result of sunspots, prominences may form • Huge arches that reach above the surface • Each one follows a magnetic field path Solar Flares • One of the most violent solar disturbances • Sudden outward eruption of electrically charged atomic particles • Cause magnetic storms on earth • Solar Flare Movie Auroras • As a result of these magnetic storms, the Aurora Borealis occurs • Solar particles are attracted to the poles by the magnetosphere • These particles come in contact with gas molecules in the upper atmosphere and produce the northern lights Formation of the Solar System • Each solar system that forms has four basic properties – Patterns of motion among large bodies – Two major types of planets – Asteroids and Comets – Exceptions to the Rules Formation of the Solar System • Solar Nebular Theory – Theory that describes the formation of the solar system – Accretion of particles began ≈5 bya Formation of the Planets • As the sun was spinning, small bodies of matter called planetismals began clumping together • Planetsimals smash together and form protoplanets Formation of the Planets • These protoplanets gain mass through accretion • Different materials in the gas cloud will condense at different temperatures • Rock planets versus gas planets Formation of the Planets • Frost Line – Determines what type of planets will form – Planets beyond frost line will be gas planets – Inside of frost line will be rock planets Formation of the Earth • 3 sources of heat – Collision of planetismals – Increasing weight of the outer layers – Radioactive materials within the earth The Solid Earth • Density Stratification – The young earth was a giant ball of molten lava – Heavier elements sink to the middle of planet • Caused the earth to separate into about 3 layers – Core – Mantle – Crust The Atmosphere • Earth managed to capture some H and He that was in the solar nebula • This first atmosphere was lost to space as a result of some cosmic force Formation of the Atmosphere • Our present day atmosphere came mostly from outgassing of materials • Outgassing is when gas escapes to the surface from inside – Volcanoes Formation of the Oceans Eventually, enough gases escaped and started to condense Some paleoclimatologists have speculated that the earth rained for ≈25 my Water would evaporate instantly back into the atmosphere Eventually the earth cooled and oceans began to form