24.1 The Study of Light
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24.1 The Study of Light. Visible light from sun is only a small part of what’s emitted Electromagnetic waves Radio waves, IR, light, UV, X-rays Wavelength is the difference ROYGBIV 186,000 miles/hr…all waves. Light. Comes in “packets” called photons Is both a waves and a particle - PowerPoint PPT Presentation
Transcript of 24.1 The Study of Light
24.1 The Study of Light24.1 The Study of Light
Visible light from sun is only a small Visible light from sun is only a small part of what’s emittedpart of what’s emitted
Electromagnetic wavesElectromagnetic waves– Radio waves, IR, light, UV, X-raysRadio waves, IR, light, UV, X-rays– Wavelength is the differenceWavelength is the difference– ROYGBIVROYGBIV
186,000 miles/hr…all waves186,000 miles/hr…all waves
LightLight
Comes in “packets” called photonsComes in “packets” called photons
Is both a waves and a particleIs both a waves and a particle
Radiation pressure is the “push” of Radiation pressure is the “push” of the particle of lightthe particle of light
Spectroscopy = the study of light’s Spectroscopy = the study of light’s propertiesproperties
SpectraSpectra
1.1. Continuous spectrumContinuous spectrum- A continuous band of colorA continuous band of color
SpectraSpectra
2. Absorption spectrum2. Absorption spectrum- Dark lines running through itDark lines running through it
SpectraSpectra3. Emission spectrum3. Emission spectrum
- Bright lines emittedBright lines emitted
A star’s spectra = its fingerprint…tells A star’s spectra = its fingerprint…tells what elements are in the star.what elements are in the star.
Doppler EffectDoppler Effect
The change in frequency, either higher The change in frequency, either higher or lower, when wave source is moving.or lower, when wave source is moving.
The pith gets higher or lower for sound.The pith gets higher or lower for sound.
Applies to any waveApplies to any wave
Higher (blue shift) – moving to usHigher (blue shift) – moving to us
Lower (red shift) – moving awayLower (red shift) – moving away
A red shiftA red shift
A blue shiftA blue shift
24.2 Tools to Study Space24.2 Tools to Study Space
Refracting TelescopeRefracting Telescope
Reflecting TelescopeReflecting Telescope
Radio TelescopesRadio Telescopes
Hubble Space TelescopeHubble Space Telescope
OthersOthers
Refracting TelescopeRefracting Telescope
Uses a big lens to focus lightUses a big lens to focus light– Upside down imageUpside down image– Blue and red light don’t focus at the Blue and red light don’t focus at the
same place!same place!– Lens is heavy and can distort imagesLens is heavy and can distort images– Not the “big” telescopes of todayNot the “big” telescopes of today
Reflecting TelescopeReflecting Telescope
Uses a big mirror to collect lightUses a big mirror to collect light+ doesn’t sag (weighs less)+ doesn’t sag (weighs less)
+ cheaper glass+ cheaper glass
+ can be bigger/stronger+ can be bigger/stronger– the second mirror is in the way of the the second mirror is in the way of the
lightlight
Optical Telescope PropertiesOptical Telescope Properties
Light gathering powerLight gathering power– Amount of light it can getAmount of light it can get
Resolving powerResolving power– Finer detail abilityFiner detail ability
Magnification powerMagnification power– Magnifies itMagnifies it
Radio TelescopesRadio Telescopes
““Sees” radio wavesSees” radio waves
Satellite dishes are good enoughSatellite dishes are good enough
Weak signals so the telescopes are Weak signals so the telescopes are huge!huge!
Poor resolution so they “hook up” Poor resolution so they “hook up” with other radio telescopeswith other radio telescopes
VLA = very large arrayVLA = very large array
Radio TelescopesRadio Telescopes
Less affected by weatherLess affected by weather
24/7 viewing24/7 viewing
See through interstellar dustSee through interstellar dust
No observatory = cheaperNo observatory = cheaper
Detect cool objects (no light seen)Detect cool objects (no light seen)
Detect human radio signalsDetect human radio signals
HSTHST
In orbit above earthIn orbit above earth
NO air interferenceNO air interference
Launched 1990Launched 1990
8 foot mirror8 foot mirror
10 billion times stronger than the 10 billion times stronger than the human eye!!!human eye!!!
24.3 The Sun24.3 The Sun
Just 1 of 10,000,000,000 stars in Just 1 of 10,000,000,000 stars in Milky WayMilky Way
Joe average starJoe average star
Only close star for studyOnly close star for study
109 earths wide109 earths wide
1.25 million earth’s volume1.25 million earth’s volume
Sun FactsSun Facts
IT’S A GAS…it doesn’t have a solid IT’S A GAS…it doesn’t have a solid surface!surface!
4 parts4 parts– InteriorInterior– PhotospherePhotosphere– ChromosphereChromosphere– CoronaCorona
InteriorInterior
Nuclear fusion provides energyNuclear fusion provides energy
4 hydrogen make 1 helium & energy4 hydrogen make 1 helium & energy
Mass is lost in reaction… Mass is lost in reaction… E = mcE = mc22!!
4 million tons of hydrogen are lost 4 million tons of hydrogen are lost each secondeach second … …
Can still last for 10 billion yrs!Can still last for 10 billion yrs!
Internal temp = 15 million degrees!Internal temp = 15 million degrees!
PhotospherePhotosphere
A 300 mile thick surface coveringA 300 mile thick surface covering
Looks grainy on surfaceLooks grainy on surface– From rising/sinking hot gasFrom rising/sinking hot gas– Convection currentsConvection currents
90% hydrogen, 10% Helium (sun)90% hydrogen, 10% Helium (sun)
6000 degrees6000 degrees
ChromosphereChromosphere
Thin atmosphere layerThin atmosphere layer
Oh boyOh boy
CoronaCorona
Another thin layer of hot gasesAnother thin layer of hot gases
Extends 600,000 miles outExtends 600,000 miles out
Hot gas “blows” out from sun = solar Hot gas “blows” out from sun = solar winds, at 500 miles/secwinds, at 500 miles/sec
Causes the Northern LightsCauses the Northern Lights
1,000,000 degrees1,000,000 degrees
The Active SunThe Active SunSpins on axis like planetsSpins on axis like planets25 days at eq, 33 days near top/bot25 days at eq, 33 days near top/botSunspots = dark regionsSunspots = dark regionsOn an 11 year cycleOn an 11 year cycleProminences – ejected materialProminences – ejected materialSolar flares – bright sunspots that Solar flares – bright sunspots that eject material and high energyeject material and high energyAurora Borealis – form solar flaresAurora Borealis – form solar flares
A radio image of the sun
