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This light has a spectrumthat depends on object’s surface temp only.Spectral curve is a graph that shows us wavelength (color) of thelight on horizontal and intensity(energy output/sec) on vertical2 Props of Thermal Radiation: Hotter objects emit more light per unit surface area at all wavelengths; the hotter object = shorter wavelength of its max output Color of thermal radiation can tell us an object’s tempWhich star has highest surface temp based on spectral curve? ASun generates energy from nuclear reactions in its core.Processes of Nuclear Energy: Fission (big atomic nucleus splits into smaller pieces-how we make nuclear energy on Earth) & Fusion (small atomic nuclei combine to make a bigger one-stars make energy)Fusion only takes place in Sun’s core bc it needs high temps-faster moving particles to overcome repulsion/densities-more particles more collisionsPhotons bounce their way out of the sun’s core. It takes about 10 trillion trillion bounces to get out of radiative zone. Granules/mottled appearance of Sun’s photosphere is result from convection Location of granulation at the arrow is brighter because hotter material is rising. Cool material falls Detecting neutrinos from Fusion would be evidence of fusion in sunNeutrino telescope (CANADA)is buried underground. Detects neutrinos turning neutrons into photons (Japan) neutrino runs into water atom in tank which creates light ~10 neutrinos per day Chromosphere: inner atmosphere,fainter than photosphere Corona: Outer atmosphere, temp up to 2mil K, very faintBoth only visible during an eclipse Sunspots region on sun’s photosphere that’s darker bc cooler.Dark center-umbralighteroutside-penumbraVisible –photosphereUV-chromosphere Xray-coronaSunspots happen wheremagnetic fields suppressconvection.Sun’s differentialrotation (Rotates fastestat equator, slowest atpoles) 11yr sunspot cycle = 22yr magnetic cycleA because Sun rotates fastest at the equator so that spot will be ahead of othersWe in solar cycle 24 Prominence when gas gets trapped in loops, photosphere to corona it becomes denser/coolerSolar Flaresoccur when intense magnetic fields in sunspot regions release their energy explosively, can emit xrays, UV, light, and radio waves Coronal Mass ejections bubbles of gas ejected from sun often associated with solar flaresAt Solar max this can happen at least twice per day, not max is maybe 1 per week CME can arrive Earth 1-4 days after and cause strong geomagnetic storms, aurorae, and power outagesEnergetic solar wind particles that enter Earth’s atmosphere create auroras Aurora Borealis–northern lights Aurora Australis-southern lightsA large flare is detected optically, how long until radio interference arrives?