S2 - Astr 1010 - Exam 1

Front 1

Celestial Sphere

Back 1

the illusion that stars lie on a sphere surrounding the earth

-greeks

-illusion bc lack depth perception when look into space (bc stars so far away)

-helps us map the sky

Front 2

Celestial Equator

Back 2

projection of Earth's equator into space
(complete circle around celestial sphere)

Front 3

Celestial Poles

Back 3

1)NORTH CELESTIAL POLE:
point directly above earth's N pole

2)SOUTH CELESTIAL POLE:
point directly above earth's S pole

Front 4

Ecliptic

Back 4

path the sun appears to follow when circling around the celestial sphere

-crosses celestial equator at 23.5* bc thats the TILT of earth's AXIS!

Front 5

Meridian

Back 5

imaginary halr circle from S horizon through the zenith to N horizon

(zenith = direct pt overhead)

-used as reference for locating objects

Front 6

Rotation

Back 6

spinning of object around axis

(earth rotates once on axis a day)
(axis = imaginary line from N pole to S pole thru center of earth)

Front 7

Revolution
aka
Orbit

Back 7

orbital motion of one object around another

(earth orbits sun once each year)

Front 8

Precession

Back 8

slowly / gradually changes orientation of earth's axis
-direction axis is pointing changes

-bc axis now points to Polaris thats the north star (so N star will change over time)

-does NOT affect amt of axis tilt (or season pattern)
-causes constellations that correspond to the solstices & equinoxes to change (bc that depends on the direction earth's axis pts in space)

--caused by gravity's effect on tilted, rotating object thats NOT a perfect sphere
-stays upright bc rotating objects tend to keep spinning around same axis [law of conservation of angular momentum]-- prevents gravity from pulling top over

Front 9

Solar System

Back 9

the sun and all the objects that orbit it

[planets moons, asteroids (rock chunks), comets (ice balls), & particles of interplanetary dust]

Front 10

galaxy

Back 10

an island of stars in space

-a few hundred million to > a trillion stars

(Milky Way = large: >100billion stars
--our solar system = halway from center to edge of disk)

**individual galaxies do not expand while universe continues to (due to gravity)

Front 11

Galaxy Clusters

Back 11

groups of galaxies

(we're in the LOCAL GROUP)

Front 12

superclusters

Back 12

areas where galaxy clusters are tightly packed

(we're in the LOCAL SUPERCLUSTER)

-between these galaxy groupings is huge empty space

Front 13

Universe

Back 13

sum total of all matter and energy

-including all superclusters and all voids between them

Front 14

"cosmic address"

Back 14

-Earth
--Solar System
---Milky Way Galaxy
----Local Group
-----Local Supercluster
------Universe

Front 15

Big Bang

(age of universe?)

Back 15

when universe expansion began

-produced only 2 elements:
1)HYDROGEN 2)HELIUM

(14 billion years ago)

-first / simplest atoms created
-more complex atoms created in stars
-when stars dies atoms expelled into space to make new stars / planets *we're starstuff*

Front 16

Scale of the Universe

Back 16

-10 Billion Light Years across

-~10^22 stars in the universe

Front 17

Universe when Sun = grapefruit?

Back 17

Earth = ballpoint

Jupiter = marble

Front 18

Life of Stars

Back 18

Birth = in clouds of gas / dust

shine due to NUCLEAR FUSION:
-atomic nuclei smash together and stick to make heavier nuclei (happens thruout life)

DIE: when it exhausts all usable fuel for fusion

---->splits off & can eventually form new stars / planets

Front 19

all elements besides
Hydrogen & Helium
were made by:

Back 19

1) NUCLEAR FUSION

or

2)NUCLEAR REACTIONS

Front 20

age of solar system?

Back 20

~ 4.6 bya

Front 21

speed of light

Back 21

300,000 km/s

(light takes 8 min from sun to earth)

Front 22

light-years

Back 22

10 trillion km / yr

---- measures how long it takes stars to reach us (bc so far away)

*unit of DISTANCE not time*

*the farther we look in the distance the further we look back in time*

Front 23

"observable universe"

Back 23

portion of the entire universe that we can potentially observe
CONSISTS ONLY OF OBJECTS THAT LIE W/I THE PAST 14 BILLION LIGHT YEARS

(beyond that - 15 bill light years would be looking to before the universe existed -- nothing to see)

Front 24

nearest star?

(other than our sun)

Back 24

Alpha Centauri

(4.4 light years away)
-3 star system

Front 25

Earth rotates what direction

Sun & Stars appear to rise/set what direction?

Back 25

from WEST TO EAST
(counterclockwise from above N pole)

--why Sun / Stars APPEAR to
RISE in EAST &
SET in WEST

Front 26

Ecliptic Plane

Back 26

a flat plane defined by earth's orbital path

(1 AU = line from earth to sun on plane)

Front 27

Earth orbits sun what direction?

Back 27

COUNTERCLOCKWISE

(same direction it rotates)

Front 28

*the entire milky way galaxy is rotating*

Back 28

*also!**most of he mas of galaxy is located outside the visible disk in the galaxy's "halo"
--no light coming from it so termed "DARK MATTER"


*some galaxies orbit the milky way*

*milky way is moving toward the Andromeda Galaxy*

Front 29

Hubble Telescope

(date & 2 facts)

Back 29

1920s by Edward Hubble

discovered:
1)virtually ever galaxy outside our Local Group is moving AWAY from us

2)the more distant the galaxy the faster it appears to be moving away

*due to the fact the ENTIRE universe is expanding

Front 30

Think about universe in 4 dimensions

Back 30

1) length
2) width
3) depth
4) TIME

Front 31

1 km =

__ miles

Back 31

1 km = .62 miles

Front 32

1 AU =

__ miles

Back 32

1 AU = 93,000,000 miles

Front 33

1 Light-Year =

___ AU

Back 33

1 Light-Year = 63,000 AU

Front 34

1 Parsec =

___ Light-Years

Back 34

1 Parsec = 3.26 light-years

Front 35

"Parsec"

Back 35

the distance to an object with an angle of ONE ARCSECOND
is 1 parsec

(parsec is equiv to 3.26 light years)

Front 36

"Constellation"

Back 36

region of the sky with well-defined borders

(set by IAU [international atronomical union])

--divided sky into 88 constellations

Front 37

"angular size"

Back 37

the angle it appears to span your field of view

*each degree is
divided into 60 arcminutes
divided into 60 arcseconds*

Front 38

"angular distance"

Back 38

angle appearing to seperate 2 objects

*each degree is
divided into 60 arcminutes
divided into 60 arcseconds*

Front 39

circumpolar stars

Back 39

near north celestial pole

-never rise or set
-ALWAYS above horizon

-make daily counterclockwise circles

Front 40

"declination"

Back 40

aka LATITUDE

-degrees N or S of the equator

Front 41

"right-ascension"

Back 41

degrees East of the
Prime Meridian

(prime meridian is 0* longitude)

Front 42

how long is ONE revolution
of earth?

Back 42

365 1/4 days

Front 43

when in N hemisphere
all stars appear to rotate

Back 43

AROUND POLARIS

(the N star)

Front 44

at Equator all stars appear to move

Back 44

vertically up & down

Front 45

Summer Solstice

Back 45

when sun is @ farthest pt North on Celestial Sphere

-moment when N hemisphere receives most direct sunlight

Front 46

Winter Solstice

Back 46

when sun is @ farthest pt South on Celestial Sphere

-moment when N hemisphere receives least direct sunlight

Front 47

Vernal Equinox

Back 47

day when sun is directly above celestial equator

(IN SPRING)

-moment when N hemisphere goes from tipped away from the sun to tipped toward the sun

Front 48

Autumnal Equinox

Back 48

when sun is directly above celestial equator

(IN FALL)

-moment when N hemisphere goes from tipped toward the sun to tipped away from the sun

Front 49

in winter we are NOT farther from the sun

Back 49

our part of the globe is simply tilted away from the sun,
causing us to receive less energy

(longer shadows)

Front 50

one complete precession (wobble)

-how long?

Back 50

every 26,000 years

Front 51

Lunar Eclipse

Back 51

-moon passes thru earth's shadow

(earth between moon & sun)

*red moon*

Front 52

Solar Eclipse

Back 52

-moon's shadow moves across earth

(moon between sun and earth)

*ring of sunlight*

Front 53

"parallax"

Back 53

near objects appear in different places when viewed from different locations

-used by astronomers to determine distance

Front 54

Zodiac

Back 54

the constellations along the ecliptic

(the ecliptic is the path the sun takes on the celestial sphere)

Front 55

during summer sunlight strikes at a steeper angle

Back 55

the steeper angle makes sunlight more concentrated

-in summer the sun follows a longer and higher path thru the sky
--->days longer w/ short midday shadows

Front 56

Qualities of the Equinoxes

Back 56

-only 2 days of year that sun rises exactly due east and sets exactly due west

-2 days when sunlight falls EQUALLY on both hemispheres

-(summer solstice = 1st day of summer)

-reflect Northern seasons
(equator gets most direct sunlight on 2 equinoxes and least on the solstices)

Front 57

why
N Hemisphere's seasons are more extreme than the S hemisphere's

Back 57

-most of earth's land lies in N hemisphere
--ocean resists temp changes

-earth moves faster in orbit when closer to sun and slower when farther (moves slower during N hemisphere's summer -- when earth's farther from sun)(& N hemisphere's summer lasts couple days longer due to this)

Front 58

length of

Moon's orbit

Back 58

27 1/3 days

*moon's ~380,000 km from earth

Front 59

"lunar phases"

Back 59

the cycle of the moon as it moves thru the sky

-thru cycle appearance & times of rising and setting change

-phase depends on moon's position relative to sun as it orbits earth

Front 60

phases of moon result from 2 qualities

Back 60

1) half the moon always faces the sun while other half faces away

2) as you look at the ball at different positions in orbit you see different combinations of bright & dark faces

*different phases reach their highest pts @ different times

Front 61

waxing phases

Back 61

phases from new to full

Front 62

waning phases

Back 62

phases from full to new

(waning = decreasing)

Front 63

moon phases listed

Back 63

-new moon

-waxing crescent

-1st Quarter

-Waxing Gibbous

-Full Moon

-Waning Gibbous

-3rd Quarter

-Waning Crescent

Front 64

"synchronous rotation"

Back 64

the fact that the moon rotates once on its axis in the same amt of time it makes 1 orbit around earth

**CAUSES US TO ALWAYS SEE THE SAME FACE OF THE MOON**(though see different phases)

Front 65

New moon occurs ....

Back 65

when moon is between sun & earth

*if on moon you see full earth when its a new moon*
{*always the OPPOSITE phase! if u were on moon*}

Front 66

moon passes thru ecliptic plane

Back 66

only twice each orbit

Front 67

"nodes"

Back 67

the 2 pts in each orbit @ which moon crosses the ecliptic plane

Front 68

2 conditions for an eclipse to occur:

Back 68

1) phase of moon must be
full (for lunar)
or new (for solar
-bc these are the only phases in which earth moon & sun lie in a straight line)

2)the new or full moon must occur when the nodes of the moon's orbit are aligned w/sun and earth (because thats the only time new and full moons are on the ecliptic plane)

Front 69

"umbra"

Back 69

where sunlight is completely blocked (central)

Front 70

penumbra

Back 70

where sunlight is only partially blocked

(lighter than umbra)

Front 71

lunar eclipse

when happens
when total / when partial

Back 71

begins the moment moon's orbit carries it into earth's penumbra

(passes thru earth's umbra when perfectly alligned [total lunar eclipse])

Partial Lunar Eclipse:
-only part of full moon passes thru the umbra

Penumbral Lunar Eclipse:
-moon passes thru earth's penumbra only

Front 72

"totality"

Back 72

time when moon is entirely engulfed in the umbra in
LUNAR ECLIPSE

dark and red (due to earth's atmosphere scattering some sunlight)

Front 73

Solar Eclipse

Back 73

Total Solar Eclipse:
-anyone in the area where moon's umbra touches earth's surface

Partial Solar Eclipse:
-anyone w/i the moon's penumbral shadow (only part of the sun blocked from view)

Annular Eclipse:
-when moon's far away from earth & umbral shadow doesn't reach earth
*RING OF SUNLIGHT AROUND DISK OF MOON*

Front 74

"eclipse seasons"

Back 74

2 periods each year when nodes of moon's orbit are aligned w/ sun

Front 75

"saros cycle"

Back 75

eclipses recur in cycle of ~ 18 yrs & 11 days

Front 76

5 planets to see w/ naked eye

Back 76

Mercury

Venus
-early evening / early morning

Mars
-reddish color

Jupiter
-2nd brightest when visible

Saturn

Front 77

"apparent retrograde motion"

of the planets

Back 77

planets usually move eastward relative to stars but occasionally reverse course & move westward

Front 78

"steller parallax"

Back 78

apparent shifting of stationary object when looking from different locations (or different eyes)

*why greeks rejected a sun-centered model*

-stars are so far away that stellar parallax is undetectable to naked eye
[nearby stars should appear to shift back and forth against distant stars bc we view stars from different places in our orbit at different times]

Front 79

ancient astronomy

how old?

Back 79

17,000 BC

Front 80

benefits of keeping track of astronomy

Back 80

social / religious needs

agriculture (when to plant / harvest)

religion (gods control heavenly events)

Front 81

ancient egyption astronomy

Back 81

-used diurnal motions as a clock

-developed 365 day calandar

-some pyramids associated w/ important celestial events

Front 82

babylonia

ancient astronomy

Back 82

-developed 60 based counting system
(still used for min, sec, angles)

-tables of planetary motion

-prediction of eclipses
&heliachal rising (first appearance after being too close to sun)

-

Front 83

china

ancient astronomy

Back 83

-records well preserved -- date back 3000 years

-oldest records of comets / eclipses / sunspots

-**Recorded supernovae**

-astronomy was tied to gov't

-astr declined in imp after 1200 AD

Front 84

greeks

ancient astr

Back 84

-defined modern constelations & many star names

-developed mythological stories about constellations

Front 85

mayans of central america

ancient astr

Back 85

-complicated, highly accurate calandar system

-precise tables for motions of moon & venus

-timed some wars on positions of venus & jupiter

-predicted eclipses

-milky way was "origin of all life" "world tree"

-built many observatories correlated w celestial allignment

Front 86

Incas of S america

ancient astr

Back 86

Cuzco (capital) laid out to mimic sky &
point to specific horizon risings

--sun's movement thru pillars marked time to plant at different altitudes

--nearly every temple had astrological allignments

Front 87

Celts

ancient astr

Back 87

-stonehenge 2000 bc
--->prob not associated w/ astr calendar

Front 88

native N americans

ancient astr

Back 88

-tracked stars to predict season change
----indicated when time to relocate

Front 89

heliocentric universe

Back 89

COPERNICUS

-planets revolve around sun

Front 90

geocentric universe

Back 90

developed by ancient greeks
-advocated by church

-didn't explain varying motion of the planets

Front 91

Copernicus

Back 91

-heliocentric universe

-determined mercury & venus closer to the sun than earth

-estimated rotation periods and distances between planets & sun

[1]

Front 92

Brahe

Back 92

-oversaw building of first modern observatory

-first to record detailed motions of planets

-recorded magnitude / brightness of supernovae (exploding star)

----disproved greek notiont that stars are close to earth and never change

[2]

Front 93

Kepler

Back 93

worked w/ brahe

developed 3 laws of planetary motion:
1)a planet's orbit is an ellipse w/ the sun at one focus

2)planets speed up when near the sun

3) P^2 = a^3
(P = orbital period (yrs)
a = length of semi-major axis)
---plants closer to sun have shorter year than those farther away

Front 94

Galileo

Back 94

discovered jupiter's moons
(not only earth has satellites)

-telescope observations supported heliocentric view

-church put him under house arrest

Front 95

Newton

Back 95

first to decribe
-physical motion
-concept of gravity
-unified physical view of the universe

-invented calculus

-until him no one understood why planets moved

-developed model that showed gravity was responsible in keeping planets in orbit

-mathematically proved kepler's 3 laws of planetary motion

Front 96

Newton's laws of motion

Back 96

1) Law Of Inertia:
-obj at rest will remain at rest -obj in motion will remain in motion
-unless acted upon by an outside force

2)F = (m)(a)
-force = (mass) (acceleration)

-force causes accelleration (change in velocity)
-force causes change in momentum
-weight = (mass)(g)


3)for every force there is an equal and opposite reaction force

Front 97

because of newton we now know....

Back 97

earth has an equatorial bulge (from moon pulling on us)

-led us to discover neptune

Front 98

ealiest known astronomical records?

Back 98

AFRICA

-predicted weather from moon

-Carved Lunar Calendar

Front 99

Seven days a week from?

Back 99

seven naked-eye objects that appeared to move among constellations:

Sun, Moon, & 5 planets recognized
[mars, mercury, jupiter, venus, saturn]

Front 100

egyptions

Back 100

obelisks determined time of day

-divided day & night into 12 parts ---> varied in length bc amt of daylight varies during the year

-eventually built water-clocks (like hourglass)

Front 101

determining time of day at night

(ancient people)

Back 101

-by position and phase of moon
[first quarter moon sets ~ midnight]

-positions of the stars
[different constellations rise at different times during different months]

Front 102

the study of ancient structure in search of astronomical connections?

Back 102

archaeoastronomy

-evaluates structures to see any particular astronomical allignments

Front 103

Pyramids

Back 103

egyptions

--oriented with cardinal directions

Front 104

developed arithmetic for later astronomical calculations?

Back 104

babylonians

Front 105

Copernicus

Back 105

SUN CENTERED MODEL

-adopted model that allowed him to calculate a planet's orbital period & distance from sun

-beleived orbits must be perfect circles STILL

Front 106

BRAHE

Back 106

observed a supernova (explosion of a distant star) -thought it was a nova (new star)
-proved it was farther away from the moon by measuring its parallax

*Best set of naked-eye observations ever made

-couldn't detect steller parallax --> concluded earth was stationary w/ sun orbiting it while other planets orbit the sun

Front 107

KEPLER

Back 107

-hired by brahe

-ABONDONED IDEA OF CIRCULAR ORBITS

-orbits are Ellipses

-3 laws of planetary motion

Front 108

Keplers 1st
law of planetary motion

Back 108

the orbit of each planet is an ellipse with the sun at one focus

{tells us planet's distance from sun varies during orbit
--closest @ perihelion
--farthest @ aphelion}

Front 109

Keplers 2nd
law of planetary motion

Back 109

as a planet moves around orbit it sweeps out equal areas in equal times

{planets travel faster when they're closer to the sun
-moves the greater distance @ perihelion
& shorter distance @ aphelion
in same amt of time}

Front 110

Kepler's 3rd
law of planetary motion

Back 110

more distant planets orbit the sun at slower speeds
obeying mathematical relationship
p^2 = a^3
(p = planet's orbital period, a = avg distance in astronomical units)

--suggested planetary motiomn might be the result of a force from the sun

Front 111

GALILEO

Back 111

answered the 3 objections to a sun based model:::

-demonstrated moving objects remain in motion unless a force acts upon it
[birds & such should stay w/ moving earth, not be left behind]

-built a telscope - saw sunspots w/imperfections
[heavens aren't perfect]

-provided strong evidence that stars were far enough away to be unable to detect steller parallax

Front 112

Ancient Aristotle
model of the universe

Back 112

-all spheres responsible for celestial motion transparent & interconnected

-earth @ center explained by gravity

-gravity pulled heavy things toward center of universe & allowed lighter things to float to heavens

Front 113

Astrology

Back 113

the apparent positions of the sun moon and planets among the stars influence human events

-predictions far less reliable than astronomical ones

-we know now that patterns of the stars in constellations are accidents
-and constellations are only the apparent associations of the stars

Front 114

sidereal day

Back 114

how long it takes for a star to go from its highest point one day to its highest point the next

(23 hrs 56 min)

represents 360* rotation of earth

Front 115

solar day

Back 115

our 24 hour day

-the time it takes the sun to make one circuit around the local sky
(from its highest point one day to its highest point the next)

*4 min longer than the sidereal

*represent ~361* rotation of earth (makes the 4 min)

Front 116

synodic month

Back 116

month comes from the moon's 29.5 day cycle

-the time required for each cycle of phases

-not moon's true orbital period

Front 117

sidereal month

Back 117

moon's true orbital period

-only ~ 27.33 days

(how long it takes moon to complete orbit relative to position of distant stars)

Front 118

sidereal year

Back 118

time it takes for earth to complete one orbit relative to stars

Front 119

tropical year

Back 119

20 min shorter than sidereal year

-in sync w/seasons
-time from spring equinox to spring equinox

(bc each year location of equinoxes and solstices shifts amoung the stars ~ 20 min worth)

Front 120

a planet's
"sidereal period"

Back 120

time planet takes to orbit sun

measured relative to stars

Front 121

planet's
"synodic period"

Back 121

time between when it's lined up with Sun one time and the next time its similar in alignment

Front 122

conjunction

Back 122

when planet is opposite the sun of earth

(planets closer to sun can experience this as "superior conjunction)

Front 123

opposition

Back 123

when earth is between the sun and the planet

(planets closer to sun can experience this as "inferior conjunction"---they never have an opposition)

Front 124

apparent solar time

Back 124

base time of sun's actual position in local sky (sundials)

-noon = precise moment when sun's highest in sky

Front 125

Newton's first law of Motion

Back 125

objects in motion stay in motion
objects in rest stay at rest
-unless acted upon by an outside force

Front 126

Newton's 2nd law

Back 126

Force = (mass)(accelleration)

Front 127

Newton's 3rd law

Back 127

for every action there's an equal and opposite reaction

Front 128

Newton

basics

Back 128

-explained why planets move

-developed model that gravity is keeping planets in their orbits

-mathematically proved kepler's 3 laws

-can now determine mass of objects, their orbits, how much force they exert on eachother

-earth has an equatorial bulge (from moon pulling)

-discovery of planet neptune

-applications of calculus

Front 129

EINSTEIN

Back 129

relativity

1905 & 1915

(special & general relativity theories)

Front 130

2 observations for relativity

Back 130

1)your description of reality is the same regardless of the constant velocity you're moving

2)speed of light is constant
and nothing is faster

Front 131

3 results of special relativity

Back 131

1) length of object decreases as speed increases

2)clocks passing by you move more slowly than clocks at rest {time dilation}
---time and space cannot be seperated & equal the single entity of "spacetime"

3)mass of an object increases as it moves faster
E = mc^2

Front 132

newton was wrong!

Back 132

newton's physics of gravity can describe small objects but don't work when applied to massive bodies or really fast speed

Front 133

einstein says objects warp the space around them

Back 133

gravity doesn't attract objects the curvature of space draws them together

Front 134

even things without mass would be attracted toward a massive body

(says einstein)

Back 134

like light

-black holes

Front 135

Types of Energy

Back 135

-Kinetic (energy of motion)

-Potential (stored)
-----a)gravitational
-----b)chemical
-----c)electrical

-thermal (heat)

-radiative (light)

-mass-energy (e = mc^2)

Front 136

mass-energy?

Back 136

E = mc^2

Front 137

laws of energy

Back 137

1)can't be created or destroyed

2)can be converted from one form to another

Front 138

"phase changes"

Back 138

occur when thermal (heat) energy is added to matter

-increasing thermal energy causes bonds to break

-decreasing thermal energy produces stronger bonds

Front 139

plasma phase

Back 139

extreme heat

-free electrons move amoung + ions

-molecular dissasociation

Front 140

gas phase

Back 140

atoms / molecules essentially unconstrained

Front 141

liquid phase

Back 141

atoms / molecules remain together but move freely

Front 142

solid phase

Back 142

atoms / molecules held tightly in place

Front 143

electromagnetic radiation

Back 143

aka LIGHT

Front 144

speed of light?

Back 144

300,000 km /sec

Front 145

light properties?

Back 145

both a Partical
and a Wave

Front 146

light's wave-like properties

Back 146

-shadow edges aren't crisp

-different colors of light have different wavelengths

Front 147

light's partical-like properties

Back 147

-can knock electrons of a surface
(photoelectric effect)
----film

Front 148

visual light

(optical spectrum)

Back 148

-blue = shorter wavelengths

-red = longer wavelengths

-white light = all the colors

-water & ice act as prisms seperating colors

Front 149

UV rays

Back 149

waves short of our detection
(shorter than blue)

Front 150

IR (infrared) rays

Back 150

waves long of our detection
(longer than red)

Front 151

Telescope types:

Back 151

1)refractor

2)reflector

Front 152

refractor telescope

Back 152

uses lenses to produce image

-good for close bright objects (planets, moon)

DRAWBACKS:
-lense causes distortion
-different light wavelengths focus on different points
-size limitations

Front 153

reflector telescope

Back 153

uses mirrors to produce images

-better for distant dim fuzzy objects

DRAWBACKS:
-blocked light from secondary mirror
-light focuses on different distances

Front 154

purposes of telescope

Back 154

brighten

resolve (sharpness)

magnify

Front 155

problems observing atmosphere from earth

Back 155

atmosphere of dust/gas/h2o/ice causes stars to twinkle

-spherical atmosphere causes distortion of shape/position/color

-light pollution

Front 156

hubble space telescope

Back 156

-orbiting earth since 1993

-gathers UV, IR, & visible light

(clear images of planets)

Front 157

Charge Coupled Devices

(CCDs)

Back 157

photographic film for astronomers

-silicon square divided into light sensitive cells (pixels)

-viewed/processed on computers

Front 158

radio astronomy

(radio telescopes)

Back 158

telescopes can look @ radiowaves

-radio dishes can be combined to form better image

-useful in detecting features like black holes

Front 159

metonic cycle

Back 159

by ancient greek astronomer

-19 year cycle

--bc takes 19 years for the lunar phases to repeat on the same dates

Front 160

18-year saros cycle

Back 160

babylonians
--predicted eclipses

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sacred round

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mayan cycle

260 days

-eclipse prediction

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first proposed sun-centered modeL?

Back 162

aristarchus

(greek)

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how did greeks explain "apparent retrograde motion"

for their geocentric modeL?

Back 163

"Ptolemaic Model"

-each planet moves around earth on a small circle that turns around a larger circle

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celestial coordinates

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coordinates are

DECLINATION:
[similar to latitude]
-parallal to celestial equator
-celestial equator = 0*
-labeled POSITIVE or NEGATIVE (not N/S)

RIGHT ASCENSION
[similar to longitude]
-0 = line that runs thru spring equinox (same as longitude)
-measures in HOURS (not E/W)
---full circle = 24 hrs
----each hr represents 15*

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stars w/
declination of:
0*
>0*
<0*

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0*: lie on celestial equator
-rise due east - set due west

>0*: rise N of due east
-set N of due west

<0*:rise S of due east
-set S of due west

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flyby

mission

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spacecraft goes past planet & continues

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orbiter

mission

Back 167

orbits planet its studying

-longer term study

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lander / probe

mission

Back 168

lands on surface
or
probes atmosphere

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return

mission

Back 169

designed to return a sample

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speed

Back 170

how far it'll go in a certain amt of time

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velocity

Back 171

tell us speed AND direction

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acceleration

Back 172

if its velocity is changing

-a change in speed or direction or both

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you don't feel any effect of moving when

Back 173

YOUR VELOCITY IS CONSTANT

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acceleration of gravity

(g)

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earth: increases by 10 m/s

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momentum

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(mass)(velocity)

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how do u change an object's momentum?

Back 176

only by applying a FORCE

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freefall

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falling without any resistence

-whenever there's nothing to prevent you from falling

-astronauts weightless when orbiting earth bc in constant state of free fall
(there is gravity in space)

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newton's third law

clarified

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for every force there's an equal and opposite force

-much greater acceleration for you than earth (bc you're so much smaller)

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white light
v
black light

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white :
all colors mixed in equal proportion

black light
absence of color

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how light & matter interact

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1)EMMISION
-emits light (turn on bulb)

2)ABSORBTION
-hand near a light -- hand absorbs light -- energy warms hand

3)TRANSMISSION
-glass / air - allow light to pass thru

4)REFLECTION / SCATTERING
-light bounces off matter
-reflection = bouncing in same direction
-scattering = random bouncing

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wavelength

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distance from one peak to the next

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frequency

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number of peaks passing by a pt each second

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frequency can also be reffered as

Back 183

cycles per second

HERTZ (Hz)

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speed of wave?

Back 184

(wavelength)(frequency) = speed

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"field"

Back 185

strength of force any particle would exerience @ a pt in space

-earth's gravitational field depends on earth's mass and the distance pt is from earth

Front 186

light's "field"

Back 186

light waves are vibrate electric AND magnetic fields

-vibrations of electric field - electron goes up and down

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wavelength & frequency related

Back 187

longer the wavelength
the lower the frequency

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photons

Back 188

light's individual particles

-can be counted individually
-each have a wavelength & frequency

-shorter the wavelength, the higher the frequency == THE HIGHER THE ENERGY OF ITS PHOTONS

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electromagnetic spectrum

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the complete spectrum of light

visible = 400-700nm

-shortest
gamma --- xrays --- UV --- visible --- IR --- (microwaves) --- radiowaves
-longest(smallest amt of energy)

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matter is composed of

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atoms
-different types = different elements

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atomic #
v
atomic mass

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atomic number = # of protons in nucleus

atomic mass = protons + neutrons
(can vary -- isotopes)

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molecules

Back 192

atoms combine to form molecules

(O2 molecule = two O atoms)

-molecules w 2+ types of atoms = compounds (H2O)

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phase changes occur..

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when one chemical bond is broken & replaced by another

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sublimation

Back 194

the process that molecules escape from a solid
(some gas always present with solid ice / liquid water)

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evaporation

Back 195

process by which molecucles escape from a liquid

[high temps = higher sublimation & evaporation]

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molecular dissociation

Back 196

at high enough temps collisions between molecules so violent they break chemical bonds holding individual h2o molecules together

molecules split into peices

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ionization

Back 197

@ temps HIGHER than molecular dissociation

collisions break bonds holding electrons around nuclei of an atom
allowing electron to go free

-leaves remaining atom w + charge

(the process of stripping electrons from atoms)

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plasma

Back 198

hot gas in which atoms have been ionized
(can be reffered to as gas or plasma... ex. the SUN!)

at temps HIGHER? than ionization

whats left becomes a hot gas of freely moving electrons & + charged ions of H &O

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pressure

Back 199

force / unit area

Front 200

pressure's effect on state changes

Back 200

higher pressure = needs higher temps to change state

(stay solid longer... & such

Front 201

what particles can interact w light?

Back 201

ONLY CHARGED PARTICLES

Front 202

how can atoms contain energy?\

(3)

Back 202

1) bc of their mass they posses mass-energy (mc^2)

2)kinetic energy bc of their motion

3)electrical potential energy
--MOST IMPORTANT
-depends on the arrangement of electrons around nuclei

Front 203

energy stored by electrons in atoms

Back 203

-electrons can have only particular amts of energy & not energy in between!!!

Front 204

"energy levels" of an atom

Back 204

the possible energies of electrons

Front 205

lowest possible energy level for electron?

Back 205

"GROUND STATE"
level 1

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"excited state"

Back 206

all possible energy levels other than ground state

(though they will quickly "calm" & return to ground state)

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"energy level transitions"

Back 207

only occur when electron gains or loses specif amt of energy seperating 2 levels
(any other amt and nothing will happen)

-the electron can gain enough energy to reach ionization level and will then escape the atom completely (ionizing the atom)

*energy levels differ from element to element*

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spectroscopy

Back 208

process of obtaining a spectrum and reading info

(look like rainbows)

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"intensity" (light)

Back 209

the amount of radiation

-proportional to (number of photons @ that wavelength)x(energy of those photons)

-lot of light = high intensity

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"continuous spectrum"

Back 210

-common bulb
=spans a broad range of wavelengths w/o interruption

Front 211

"emission line spectrum"

Back 211

low density cloud
-emits light only @ specific wavelengths

-spectrum consists of bright emission lines against black background

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"absorbtion line spectrum"

Back 212

cloud between us and bulb

-cloud absorbs specific wavelengths but we still see most of the continuous light of bulb

--spectrum = dark absorption lines against background rainbow

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when electrons go back to ground state...

Back 213

they emid a photon of light (when they release that energy)

-the photon released has the same energy the electron lost
=== specific Wavelength & frequency

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"chemical fingerprints"

Back 214

hydrogen emits and absorbs light at specific WL's = can detect its presence in distant objects (only H produces a certain set of lines)

-molecules can vibrate and rotate and also produce spec. spectra (molecular bands)

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thermal radiation

Back 215

the temperature dependence of light
-photon energies depend only on objects temp (not what obj made of)

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hotter object emit photons....

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hotter = emits more light

hotter = emits photons w higher energy (shorter wavelengths)

-first turning on light glows red ... hotter gets blue

-cool star = red light

-hotter stars = blueish

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doppler effect

Back 217

moving toward you - higher pitch
-each pulse a lil closer
-waves get bunched
--gives them shorter WL
--higher frequency

moving away from you - lower pitch
-each pulse from farther away
-stretches out WLs
---giving them lower frequency

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doppler effect applied to light

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-moving toward us
-light waves bunch
-shorter WLs
"BLUESHIFT"

-moving away
-longer WLs
"REDSHIFT"

Front 219

"rest wavelengths" applied to light

Back 219

the wavelengths of hydrogen lines in stationary clouds

-if lines appear longer = REDSHIFT

-lines seem shorter = BLUESHIFT

(can also tell if rotating)

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how lens' work

Back 220

light hits lens
-slows down
-causes light to bend
(farther from center = bent more)
-converge to pt - FOCUS
-forms image of original obj
-image appears on "focal plane"

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CCDs

Back 221

"charge coupled devices"
-chip of silicon VERY sensitive to photons
-divided into grid (pixels)
-when photon strikes pixel == electric charge accumulates

-more sensitive to light than normal film
-accurately records 90% of photons that strike them
-can records BOTH DIM & BRIGHT light @ same time

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telescope's "light collecting area"

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how much total light telescope can collect at a time

-by diameter of lca

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telescope's angular resolution

Back 223

smallest angle over which we can tell 2 dots are distinct

-depends on their actual seperation & their distance from us

-larger = higher angular resolution
-earth's atmosphere limits angular resolution

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telescope's "diffraction limit"

Back 224

the angular resolution a telescope could acheive if it were limited only by light wave interference

-depends on diameter of telescops mirror & WL being observed

-larger telescops = smaller diffraction limit

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spectrographs

Back 225

use diffraction grating to seperate various colors of light into spectra -- then recorded w CCD

-can reveal chemical comp, temp, & rotation rate from spectrum BUT depends on SPECTRAL RESOLUTION
(higher = more detail)
--depends on how much spectrograph spreads out light...spreads out light too much = dim

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"light curves"

Back 226

graphs that show how objects intensity varies w time

Front 227

arctic circle
v
antarctic circle

Back 227

arctic = N

antarctic = S

Front 228

difference between
"special" & general relativity

Back 228

special - shows that space and time are intertwined - IGNORES gravity

general - offers new view of gravity --explains expansion of universe & black holes
-applies WITH OR WITHOUT gravity

Front 229

theory of relativity leads to....

Back 229

-no info can travel faster than speed of light

-moving faster = time moves slower

-moving faster = length is shorter

-faster = mass is greater
(E = mc^2)

Front 230

2 absolutes of relativity

Back 230

-motion is relative NOT everything

1)laws of nature same for everyone

2)speed of light same for everyone