“Once you can accept the universe as being something ...raghavan/astr1010/Class_01.pdf · Things to Purchase • New textbook $113 – "The Cosmic Perspective 4th edition“ •

“Onc

e yo

u ca

n ac

cept

the

univ

erse

as

bein

g so

met

hing

exp

andi

ng in

to a

n in

finite

not

hing

whi

ch is

som

ethi

ng,

wea

ring

strip

es w

ith p

laid

is e

asy.

”A

lber

t Ein

stei

n

AS

TR

101

0: A

stro

nom

y of

the

Sol

ar S

yste

m

Fal

l 200

7M

on/W

ed/F

ri 11

:00

a.m

. –11

:50

a.m

.A

derh

old

Lear

ning

Cen

ter

5

Dee

pak

Rag

hava

n

“The

div

ersi

ty o

f the

phe

nom

ena

of n

atur

e is

so

grea

t, an

d th

e tr

easu

res

hidd

en in

the

heav

ens

so r

ich,

pre

cise

ly in

ord

er th

at th

e hu

man

min

d sh

all n

ever

be

lack

ing

in fr

esh

nour

ishm

ent.”

Joha

nnes

Kep

ler

1597

-16

30

Why

Ast

rono

my?

Cha

pter

1 o

peni

ng fi

gure

Top

ics

Cov

ered

in th

is C

ours

e

•T

he b

ig p

ictu

re u

nder

stan

ding

of t

he c

osm

os•

Com

mon

obs

erva

tions

–U

nive

rse

as v

iew

ed f

rom

the

Ear

th

–S

easo

ns, L

unar

Pha

ses,

Ecl

ipse

s

•D

evel

opm

ent o

f ast

rono

my

thro

ugh

the

ages

•P

hysi

cal l

aws

of th

e un

iver

se•

Ligh

t and

its

inte

ract

ion

with

mat

ter

•T

eles

cope

s &

Tec

hniq

ues

•S

olar

Sys

tem

For

mat

ion

•T

he S

un, P

lane

ts, M

oons

, and

oth

er S

S b

odie

s•

Ext

raso

lar

plan

ets

•Li

fe o

n E

arth

and

in th

e U

nive

rse

Ass

essi

ng Y

our

Per

form

ance

•4

Hom

ewor

k A

ssig

nmen

ts

15%

•In

-cla

ss A

ctiv

ities

/Qui

zzes

10

%•

Labo

rato

ry w

ork

25%

•In

-cla

ss E

xam

s (B

est 2

of 3

) 30

%•

Fin

al E

xam

on

Dec

embe

r 12

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radi

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Key

s to

You

r S

ucce

ss

•“E

ight

y pe

rcen

t of s

ucce

ss is

sho

win

g up

” -

Woo

dy A

llen

•P

artic

ipat

e ac

tivel

y in

the

clas

sroo

m•

Sto

p m

e fo

r qu

estio

ns, c

larif

icat

ions

, com

men

ts•

Don

’t fo

rget

the

labs

!•

Off

ice

Hou

rs–

I wan

t all

of y

ou to

suc

ceed

–If

you

need

ext

ra h

elp,

ple

ase

com

e se

e m

e!•

Wor

k H

ard

–I’l

l try

to c

halle

nge

you,

but

als

o su

ppor

t you

and

m

ake

it fu

n•

Util

ize

the

clas

s w

ebsi

te:

http

://w

ww

.cha

ra.g

su.e

du/~

ragh

avan

/teac

hing

.htm

l

Thi

ngs

to P

urch

ase

•N

ew te

xtbo

ok$1

13–

"The

Cos

mic

Per

spec

tive

4th

editi

on“

•B

enne

tt, D

onah

ue, S

chne

ider

, Voi

t

–C

omes

with

•

Ast

rono

my

Med

ia W

orkb

ook

•M

aste

ring

Ast

rono

my

web

site

acc

ess

–U

sed

book

$85

, doe

s no

t inc

lude

web

acc

ess

($22

)

•La

b w

orkb

ook

$ 41

.95

–A

ctiv

ities

in A

stro

nom

y, 2

007-

2008

edi

tion

•Jo

hn W

ilson

–U

sed

copy

will

not

wor

k!

•La

b m

ater

ials

car

d$

20–

At t

he G

SU

boo

ksto

re

–S

ubm

it to

lab

inst

ruct

or

•A

ll th

is w

ill w

ork

for

AS

TR

102

0 as

wel

l

A F

ew T

hing

s T

hat I

Ask

of Y

ou

•T

urn

off c

ell p

hone

s, p

ager

s et

c.•

Don

’t w

ork

on o

ther

stu

ff w

hile

in c

lass

•D

on’t

dist

urb

clas

s w

ith s

ide

disc

ussi

ons

•If

you

mus

t lea

ve d

urin

g cl

ass,

ple

ase

do

so q

uiet

ly•

Par

ticip

ate,

Inte

ract

, Enj

oy…

So,

let t

he jo

urne

y be

gin!

Wha

t We

Will

Lea

rn T

oday

•W

here

did

we

com

e fr

om?

–Y

our

pers

onal

con

nect

ion

to a

stro

nom

y

•W

hat i

s a

“sci

ence

”?•

Wha

t is

our

plac

e in

the

univ

erse

?•

How

can

we

lear

n ab

out h

ow th

e un

iver

se

was

in th

e pa

st?

Whe

re D

id Y

ou C

ome

Fro

m?

“We’

re a

ll st

ar-s

tuff”

Car

l Sag

an

Fig

1.2

A Q

uick

Rec

ap o

f Uni

vers

al H

isto

ry•

Sta

rts

with

a “

Big

Ban

g” a

bout

14

billi

on y

ears

ago

–S

eede

d th

e un

iver

se w

ith H

ydro

gen

& H

eliu

m

•S

ets

into

a p

erpe

tual

exp

ansi

on•

Loca

l poc

kets

of m

atte

r co

nden

se to

form

gal

axie

s, a

nd

with

in th

em, s

tars

•S

tars

bur

n hy

drog

en to

hel

ium

, and

suc

cess

ivel

y, to

hi

gher

ele

men

ts in

thei

r co

re•

The

mor

e m

assi

ve s

tars

die

in a

spe

ctac

ular

exp

losi

on

(sup

erno

va)

blas

ting

the

elem

ents

into

spa

ce•

Nex

t gen

erat

ion

star

s &

pla

nets

(in

clud

ing

terr

estr

ial)

form

with

the

help

of t

hese

hig

her

elem

ents

•A

t lea

st o

ne p

lane

t fos

ters

life

!•

A fe

w o

f the

se li

ving

bei

ngs

regi

ster

for

this

ast

rono

my

cour

se!

Ast

rono

my

is a

Sci

ence

•S

cien

ceis

the

pro

cess

of a

cqui

ring

know

ledg

e ga

ined

via

a r

igor

ous

tech

niqu

e ca

lled

the

scie

nti

fic

met

ho

d

•S

cien

ce is

no

ta

body

of

fact

sF

ig 3

.25

The

Hal

lmar

ks o

f Sci

ence

•T

he s

impl

est

expl

anat

ion

win

s!–

Occ

am’s

Raz

or

•V

erifi

able

Obs

erva

tions

Fig

3.2

6

Sci

entif

ic T

heor

y

•T

he m

eani

ng o

f the

ory

is d

iffer

ent i

n sc

ienc

e th

an in

eve

ryda

y lif

e•

In s

cien

ce, a

theo

ry is

not

the

sam

e as

a

hypo

thes

is, r

athe

r:•

A s

cien

tific

theo

ry m

ust:

–E

xpla

in a

wid

e va

riety

of o

bser

vatio

ns w

ith a

fe

w s

impl

e pr

inci

ples

–M

ust b

e su

ppor

ted

by a

larg

e, c

ompe

lling

bo

dy o

f evi

denc

e–

Mus

t NO

T h

ave

faile

d an

y cr

ucia

l tes

t of i

ts

valid

ity

Mat

hem

atic

s in

Ast

rono

my

•R

emem

ber

it is

a to

ol to

hel

p yo

u•

We

will

onl

y ne

ed c

alcu

latio

ns a

nd s

impl

e al

gebr

a–

You

will

be

usin

g a

scie

ntifi

c ca

lcul

ator

•C

ome

see

me

if yo

u ne

ed h

elp

Anc

ient

Pon

derin

gs

•H

ow d

o w

e kn

ow w

hat w

e kn

ow?

–F

lat E

arth

or

Rou

nd E

arth

?–

Sun

aro

und

Ear

th o

r E

arth

aro

und

Sun

?

You

r C

osm

ic A

ddre

ss

Let’s

wat

ch th

e P

ower

s of

Ten

Mov

ie…

Fig

1.1

Mai

n P

oint

s S

een

in th

e M

ovie

•T

he U

nive

rse

is e

xtre

mel

y la

rge

(102

6m

)•

The

re is

a lo

t goi

ng o

n ev

en in

the

mic

rosc

opic

rea

lm–

We’

ve s

een

stru

ctur

e do

wn

to 1

0-18

m

•T

he U

nive

rse

is m

ostly

em

pty

–O

n la

rge

scal

es (

sola

r sy

stem

, gal

axy

etc.

)–

On

smal

l sca

les

(ato

ms,

mol

ecul

es e

tc.)

•Lo

cal p

ocke

ts o

f den

sity

mak

e th

e U

nive

rse

inte

rest

ing

The

Cos

mic

Jou

rney

•In

this

cou

rse,

we’

ll di

scus

s al

l 40

orde

rs o

f mag

nitu

de

cove

red

in th

e m

ovie

!•

We

deal

with

the

extr

emel

y sm

all…

–S

ize

of a

n at

om ~

0.0

0000

0000

1 m

•T

o th

e ve

ry la

rge…

–D

ista

nce

to n

eare

stst

ar ~

40,

000,

000,

000,

000,

000

m•

We

use

two

tool

s to

hel

p us

–S

cien

tific

Not

atio

n•

103

= 1

,000

•10

-3=

0.0

01

–In

vent

new

uni

ts•

Ang

stro

m =

10-

10m

(ap

prox

. the

siz

e of

an

atom

)

•Li

ght-

Yea

r ~

101

3km

(or

der

of th

e di

stan

ce to

the

near

est s

tar)

The

Spe

ed o

f Lig

ht

•30

0,00

0 km

/s =

186

,000

mile

s/s

= 6

70 m

illio

nm

ph•

Ext

rem

ely

fast

, but

stil

l a fi

nite

spe

ed•

Aro

und

the

Ear

th ~

8 ti

mes

in o

ne s

econ

d!•

To

the

Moo

n ~

1 s

econ

d•

To

the

Sun

~ 8

min

utes

•T

o th

e ne

ares

tsta

r ~

4 y

ears

•T

o th

e ne

ares

tgal

axy

~ 2

.5 m

illio

nye

ars

1 Li

ght Y

ear

= D

ista

nce

trav

elle

d by

ligh

t in

one

year

App

roxi

mat

ely

6 tr

illio

n m

iles

Ligh

t Yea

r

•1

Ligh

t Yea

r =

Dis

tanc

etr

avel

led

by li

ght

in o

ne y

ear.

•D

ista

nce

= S

peed

x T

ime

1 ly

= s

peed

of l

ight

x 1

yea

r of

tim

e=

300

,000

km

/s x

(36

5 x

24 x

60

x 60

s)=

9,4

60,0

00,0

00,0

00 k

m1

light

yea

r is

–A

ppro

xim

atel

y 10

trill

ion

km–

6 tr

illio

n m

iles

•N

ote:

The

nea

rest

sta

r is

abo

ut 4

lyaw

ay

Look

-bac

k T

ime

•T

he fa

rthe

r w

e lo

ok o

ut, t

he fu

rthe

r in

to th

e pa

stw

e se

e!–

Dire

ct c

onse

quen

ce o

f the

fini

te s

peed

of

ligh

t

•T

he S

un w

e se

e is

as

it w

as 8

m

inut

es a

go!

•A

ndro

med

a G

alax

y is

a 2

.5 m

illio

n ye

ars

old

imag

e!

Fig

1.5