ast161art

Looking Southfrom Syene Egypt

Latitude: 24º N

Scorpius

Looking Southfrom Athens Greece

Latitude: 38º N

Scorpius

Earth Shadow during Lunar Eclipse

Multiple ExposurePhotograph

Alexandria

Cyrene

Tropic of CancerSyene

Syene

Alexandria

Earth

7 14/60º

Sunlight

North Pole

South Pole

Equator

South Pole

Equator

North Pole

Meridian

North Pole

South Pole

Equator

South Pole

Equator

North Pole

Meridian

South Celestial Pole

North Celestial Pole

Celestial Sphere

CelestialEquator

SCP

NCP

CelestialMeridian

CEq

Declination

N

W

E

S

Horizon

ZenithLocal Sky

SCP

NCP

CEq

Below theHorizon

N

S

EW

Z

Visible Halfof the Sky

Horizon

MeasuringLatitude

N

W

E

S

NCPCEq

Zenith

Latitude

NS

W

E

Z

NCP

Equator

Z NCP

NS

W

E

40º N Latitude

ZNCP

North Pole

Zenith

W

E

S N

NCP

CEq

Never Sets

Above Horizon for 12h

Above Horizon for > 12h

Above Horizonfor < 12h

Never Rises

SCP

NCP

CEq

Ecliptic

~23.5ºObliquity of the Ecliptic

Cancer

Gemini

Taurus AriesPisces Aquarius

Capricorn

Sagittarius

Scorpius

LibraVirgo

Leo

March 1999: Sun in Pisces

Cancer

Gemini

Taurus Aries Pisces Aquarius

Capricorn

Sagittarius

Scorpius

LibraVirgo

Leo

September 1999: Sun in Virgo

Cancer

Gemini

Taurus Aries Pisces Aquarius

Capricorn

Sagittarius

Scorpius

LibraVirgo

Leo

December 1999: Sun in Sagittarius

Cancer

Gemini

Taurus AriesPisces Aquarius

Capricorn

Sagittarius

Scorpius

LibraVirgo

Leo

June 1999: Sun in Gemini

SCP

NCP

CEq

WinterSolstice

SummerSolstice

Ecliptic

SCP

NCP

CEq

WinterSolstice

SummerSolstice

VernalEquinox

AutumnalEquinox

Ecliptic

W

E

S N

NCPSummer Solstice

Vernal & AutumnalEquinoxes

Winter Solstice

Z

CEq

W

E

S N

NCP

CEq

Summer Solstice

Vernal & AutumnalEquinoxes

Winter Solstice

Z

December

March

June

September

Equinoxes: March 20 & Sept. 22

Northern Spring/Fall

Southern Fall/Spring

December 21: Winter Solstice

Northern Winter

Southern Summer

June 21: Summer Solstice

Northern Summer

Southern Winter

1 KW/m2 1 KW/m2

1 m2 2 m2

2000 Dec 21: Winter Solstice

2001 June 21: Summer Solstice

2001 Mar 20: Vernal Equinox

2001 Sept 22: Autumnal Equinox

Winter

Summer

Summer

Winter

Spring

Autumn

Autumn

Spring

Draco

Ursa Minor

Cepheus

Thuban

Polaris

2000 AD

2700 BC

North Ecliptic Pole North Celestial Pole

2000 AD

Rotate EastwardPrecess Westward

North Ecliptic PoleNorth Celestial Pole

15000 AD

Precession of the Equinoxes

Moon at Perigee Moon at Apogee

New Moon Full Moon

Waning Crescent

Last Quarter

Waning Gibbous

Waxing GibbousWaxing Crescent

First Quarter

Sunset

Sunrise

MidnightMoonset

NoonMoonrise

Moonrise & Moonset at 1st Quarter

SunsetMoonrise

MoonriseSunrise

MidnightNoon

Moonrise & Moonset at Full Moon

Sunset

Sunrise

MidnightMoonrise

NoonMoonset

Moonrise & Moonset at Last Quarter

Sidereal vs. Synodic Months

NewMoon

T=0d

T=27.3d

(Sidereal)

T=29.5d

(Synodic)

Penumbra

Sun Earth

Umbra

Sunlight

Uneclipsed Moon

Penumbral Eclipse

Total Lunar Eclipse

Partial Lunar Eclipse

Total Lunar Eclipse (Note the ruddy scattered sunlight)

Partial Lunar Eclipse

SunlightUmbra

PenumbraMoon

Earth

SCP

NCP

CEqEcliptic

4th

1st

2nd

3rd

Cross-QuarterDays

WinterSolstice

SummerSolstice

VernalEquinox

AutumnalEquinox

NoonT=0h

T=23h 56m 04s

(Sidereal Day)

T=24h

(Solar day)

Noon

Not to Scale

Solar & SiderealDays

InferiorConjunction

SuperiorConjunction

Earth

Maximum Eastern Elongation

Maximum WesternElongation

Earth

ConjunctionOppositionEarth

Opposition Conjunction

EasternQuadrature

WesternQuadrature

Earth

Mars Retrograde Motion in 1994/95

1995 Jan 2

1995 Mar 24 1994 Sept 24

1995 July 4

Saturn & Jupiter4/1999 - 6/2000

Saturn

Jupiter

Mars 11/1998-10/1999

Venus 6-11/1999Mercury

10-12/1999

SCP

NCPCelestial Sphere

(Daily E-W Motion)Ecliptic Sphere(Annual W-E Motion

23.5º tilt)

Planetary Spheres(Retrograde Motions)

LessTime

MoreTime

First Quarter

Last QuarterNot to Scale

EarthDeferent

Epicycle

Earth

Equant

Center

Saturn

Mars

Jupiter

Sun

MercuryVenus

Earth

Ptolemaic System

Mars

Jupiter

Saturn

EarthVenus

Mercury

Sun

Solar System

EarthMars

Retrograde Motion

Venus Maximum Eastern Elongation

1 AU

DVenus46º

VenusD 1 AU sin(46 )0.719 AU

F1 F2

Semimajor Axis

Center

T=0d

T=10d

T=0d

T=10d Equal Areas in Equal Times

Jan 10

Jan 11

Jan 12

Jan 13

Jan 19

Jan 18

Jan 15

Jan 16

Io

Europa Ganymede

Callisto

Ptolemaic System

3

3

4

4

2

2

1

1

5

5

6

6

6

6

5

5

4

4

3

3

2

2

1

1

Copernican System

Falling Apple:Changing Speed

(gets faster as it falls)Same Direction

(always falls down)

Ball Swung around on a String:Same Speed,

(in uniform circular motion)Changing Direction

(swinging around the circle)

Donut Swung around on a String

Force

Acceleration

Force = (apple’s mass) (acceleration due to gravity)

Equal and OppositeForce from the Table

Net Force is Zero, No Net Motion

M1 M2

d

M1 M2

2d

1 2 1 22 2

1(2 ) 4GM M GM MFd d

1 22

GM MFd

M1 M2

d/21 2 1 2

2 24( / 2)GM M GM MFd d

2M1

M2

d1 2 1 22 2

(2 ) 2G M M GM MFd d

M1 M2

d 1 22

GM MFd

2M1

2M2

d1 2 1 2

2 2

(2 )(2 ) 4G M M GM MFd d

Parabola Hyperbola

Circle Ellipse

Conic Section Curves

Parabolav = vE

Hyperbolav>vE

EllipsevC<v<vE

Circlev = vC

Ellipse

v<vC

Columbus, Ohio40º N: 1280 km/h

Arctic Circle66.5º N: 666 km/h

Equator1670 km/h

6 hours later

Towards Sirius

Wavelength ()

Speed (c)

Frequency (f) (# waves/second)

d=1

d=2

d=3

B=1

B=1/9

B=1/4

Doppler Effect in Sound

High Pitch(short waves)

Low Pitch(long waves)

T=0s

0 popped16 unpopped

T=35s

8 popped8 unpopped

Half-Life = 35 sec

Hot GasFaster Average Speeds

Cool GasSlow Average Speeds

Spectrum

Prism

WhiteLight

Prisms disperse light into its component colors

ContinuumSource

Continuous Spectrum

Absorption-lineSpectrum

Emission-line Spectrum

Cloud of Hydrogen Gas

Hydrogen

Helium

Oxygen

Neon

Iron

ContinuumSource Cloud of

Hydrogen Gas

LampLight

Absorbedby

HydrogenAtomsin theCloud

Lamp emits light at all energies

n=1 (Ground State)

n=3 (2nd excited state)

n=2 (1st excited state)

n=4n=5

Energy Level Diagram of 1H

Continuum

n=

n=1 (Ground State)

n=3 (2nd excited state)

n=2 (1st excited state)

n=4n=5

n=3262 52 42

Larger Jump = More Energy = Bluer Wavelength

n=6

n=1 (Ground State)

n=3 (2nd excited state)

n=2 (1st excited state)

n=4n=5

Photons of all other energies (wavelengths) are ignored and pass on by unabsorbed.

n=2326 25 24n=6

Spectrum of a Fluorescent Light

Mercury

Collecting Area

Lens

Retina

Simple Refracting Telescope

Objective Lens

Secondary Lens (Eyepiece)

Focus

PrimaryMirrorPrime

Focus

Secondary Mirror

Cassegrain Focus

238U

206Pb

235U

207Pb

4.5 Billion Years Ago238U

206Pb

235U

207Pb

Today

1 half-life 6.3 half-lives

50% left 1.2% left

Seismic Station

LowerMantle

Core

UpperMantle

Crust

Seismic Station

SurfaceWaves

P-waves

S wavesP & Swaves

Earthquake!

Near Side Far Side

Two Faces of the Moon

Maria Impact Basin

CrateredHighlands

A12 A14

A15A17

A11A16

L24L20

L16

Apollo and Luna Landing Sites

Mars

EarthVenus

Mercury

Pluto

Neptune

Uranus

Saturn

Jupiter

Pluto

Ecliptic

MolecularHydrogen

MetallicHydrogen

“Ice”

Rock

Jupiter Interior

MolecularHydrogen Metallic

Hydrogen

“Ice”

Rock

Saturn Interior

Interiors of Uranus & Neptune

Uranus Neptune

RockyCores

Slushy“Ice”Mantles

MolecularHydrogen

MetallicHydrogen

Jupiter Saturn

Uranus Neptune

Earth

S

S

P

P

Star’s spectrum shifts redward

Star’s spectrum shifts blueward