24.1 the study of light visible light from sun is only a small part of whats emitted electromagnetic...

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