Astronomy, Chapters 5-9, From Essential Cosmic Perspective

Front 1

Atomic number

Back 1

# of protons in nucleus

Front 2

atomic mass #

Back 2

# of protons and neutrons in nucleus

Front 3

isotope

Back 3

same # of protons but diff # of neutrons

Front 4

molecules

Back 4

consist of 2 or more atoms

Front 5

name 4 ways light and matter interact

Back 5

-emission
-absorption
-transmission (transparent transmits, opaque blocks/absorbs)
-reflection or scattering

Front 6

what is matter?

Back 6

atoms, which are in turn made of protons, neutrons, & electrons.

Front 7

what are ions?

Back 7

electrically charged atoms.

Front 8

what are energy levels?

Back 8

possible energy levels that an atom can have. they can only have certain levels of energy-- those in between are not possible.

Front 9

when can an electron change energy levels?

Back 9

when it gains or loses the amount of energy separating the levels.

Front 10

what is the lowest possible energy level called & what is it defined as? What about higher levels?

Back 10

its called level one -- "the ground state". defined as energy of 0 eV.

Higher energy levels are called excited states.

Front 11

what is the ionization level

Back 11

the energy level at which an electron can escape the atom.

Front 12

when does an atom become an ion?

Back 12

when an electron reaches the ionization energy level and escapes the atom, thus ionizing (charging) the atom.

Front 13

what are the three types of spectra?

Back 13

-continuous spectrum
-emission line spectrum (bright against dark)
-absorption line spectrum (dark against bright)

Front 14

how is a continuous spectrum formed?

Back 14

passing visible light through a prism

Front 15

how is an emission line spectrum formed?

Back 15

passing light of a warm gas cloud through a prism.

-the wavelengths (colors) of light it emits depends on the clouds composition and temp.

Front 16

how is an absorption line spectrum formed?

Back 16

light from hot source passes through a cooler gas cloud

Front 17

what allows us to learn the compositions of distant objects in the universe?

Back 17

the fact that every atom, ion, and molecule has certain energy levels that determine the wavelengths at which emission or absorption lines will appear on the spectrum.

Front 18

WHY do gas clouds have emission line spectrums?

Back 18

the atoms all bump into eachother. sometimes this causes atoms' electrons to jump to a higher energy level, and then to jump back down to level 1. The energy that they lose when they jump back down to level 1 must go somewhere- usually it is emited as a photon of light. the specific amount of energy lost has a wavelength & frequency.

Front 19

WHY does an absorption line spectrum occur when a hot light source passes through a cooler gas cloud?

Back 19

absorption lines occur when photons cause electrons to rise to higher energy levels.

Front 20

how do we know distant objects' chemistry?

Back 20

the spectra of certain elements have certain emission / absorption lines.

Front 21

how does light tell us about an objects temperature?

Back 21

we can observe continuous spectrum lines that they produce.

Front 22

what determines an objects thermal radiation spectrum? why?

Back 22

its temperature, because the average kinetic energy of an objects atoms/ molecules = temperature.

Front 23

what are the 2 laws of thermal radiation?

Back 23

-hotter objects emit more light per square meter at all wavelengths

-hotter objects emit photons with higher avg energy (aka, w/ shorter wavelengths.

Front 24

how can we learn about the motion of distant objects?

Back 24

through the doppler effect.

Front 25

what kind of shift do objects have moving toward us? from us?

Back 25

toward us: blushifts. (shorter wavelengths)

from us: redshifts. (longer wavelengths.

Front 26

how is an absorption line spectrum formed?

Back 26

light from hot source passes through a cooler gas cloud

Front 27

what allows us to learn the compositions of distant objects in the universe?

Back 27

the fact that every atom, ion, and molecule has certain energy levels that determine the wavelengths at which emission or absorption lines will appear on the spectrum.

Front 28

WHY do gas clouds have emission line spectrums?

Back 28

the atoms all bump into eachother. sometimes this causes atoms' electrons to jump to a higher energy level, and then to jump back down to level 1. The energy that they lose when they jump back down to level 1 must go somewhere- usually it is emited as a photon of light. the specific amount of energy lost has a wavelength & frequency.

Front 29

WHY does an absorption line spectrum occur when a hot light source passes through a cooler gas cloud?

Back 29

absorption lines occur when photons cause electrons to rise to higher energy levels.

Front 30

how do we know distant objects' chemistry?

Back 30

the spectra of certain elements have certain emission / absorption lines.

Front 31

how does light tell us about an objects temperature?

Back 31

we can observe continuous spectrum lines that they produce.

Front 32

what determines an objects thermal radiation spectrum? why?

Back 32

its temperature, because the average kinetic energy of an objects atoms/ molecules = temperature.

Front 33

what are the 2 laws of thermal radiation?

Back 33

-hotter objects emit more light per square meter at all wavelengths

-hotter objects emit photons with higher avg energy (aka, w/ shorter wavelengths.

Front 34

how can we learn about the motion of distant objects?

Back 34

through the doppler effect.

Front 35

what kind of shift do objects have moving toward us? from us?

Back 35

toward us: blushifts. (shorter wavelengths)

from us: redshifts. (longer wavelengths.

Front 36

objects moving ____ and ____ from us can be subjected to the doppler test to determine their speed

Back 36

directly toward and directly away from us.

Front 37

what kind of mirror does a REFLCTING telescope use?

Back 37

a curved primary mirror.

Front 38

what is the primary type of telescope used MODERNLY?

Back 38

reflecting

Front 39

what are REFRACTING telescopes based on?

Back 39

transparent glass lenses that collect and focus light

Front 40

what was the type of telescope used during Galileo's time?

Back 40

refracting.

Front 41

what is adaptive optics, & how does it work?

Back 41

eliminates blurring caused by atmosphere. how it works: mirrors in the telescope are electronically adjusted to cancel out the atmospheric distortion.

Front 42

what is interferometry?

Back 42

spacing out several telescopes and linking them in order to achieve greater angular resolution.

Front 43

where do most asteroids orbit?

Back 43

asteroid belt, between mars and jupiter.

Front 44

where do comets orbit?

Back 44

kuiper belt, beyond neptune's orbit.

Front 45

where is the oort cloud & what orbits in it

Back 45

comets orbit the sun in the oort cloud, which is a distant spherical region.

Front 46

name two "exceptions to the rule"

Back 46

uranus rotates "sideways"
earth has a large moon.

Front 47

name jupiter's moons

Back 47

io
europa
ganymede
callisto

Front 48

summarize the nebular theory.

Back 48

our solar system formed from a giant cloud of gas.

best explains the features of our solar system.

Front 49

what features clue us into the formation of our solar system?

Back 49

-motions of large bodies
-2 major planet types
-swarms of small bodies
-notable exceptions

Front 50

what does the law of conservation of angular momentum state?

Back 50

as the radius decreases, rotational speed increases.

Front 51

what theory explains earths large moon?

Back 51

the giant impact theory

Front 52

where did earths water come from?

Back 52

possibly from impacts w/ icy planetesimals

tells us how long its been since a rock last solidified-- not necessarily when it formed.

Front 53

how does radiometric dating work?

Back 53

measuring the proportions of various atoms & isotopes in a rock

Front 54

half-life

Back 54

the time it would take for half the nuclei in a collection to decay.

Front 55

how do we detect planets around other stars?

Back 55

direct detection: pictures of spectras of planets

indirect detection: measuring the effect planets have on their stars

Front 56

Doppler technique

Back 56

measures gravitational tug that planets place on their star, by looking for doppler shifts in a stars spectrum.

Front 57

astrometric technique

Back 57

measuring differences in the stars positioning

Front 58

first extrasolar planet discovered?

Back 58

planet orbiting star: 51 pegasi

Front 59

what are the 3 layers of terrestrial planets?

Back 59

core, mantle, crust.

Front 60

what is the lithosphere?

Back 60

a planet's outer layer of cool, rigid rock. includes the crust and part of the upper mantle. "floats" on the warmer softer rock beneath.

Front 61

define: differentiation

Back 61

the process by which gravity causes material to separate by density

Front 62

what causes geological activity on planets?

Back 62

internal heat!

Front 63

define: convection

Back 63

process by which hot material expands and rises while cooler material contracts and falls.

earth: 100 billion yrs.

Front 64

conduction ...

Back 64

transfers heat from hot material to cool material.

Front 65

radiation

Back 65

sends energy into space

Front 66

what causes a planet's magnetic fields?

Back 66

Moving charged particles create magnetic fields.
A planet’s interior can create magnetic fields if its core is electrically conducting, convecting, and rotating.

Front 67

define: magnetosphere

Back 67

protective bubble that deflects most of the charged particles from the sun around our planet.

Front 68

what 4 processes shape earth's surface?

Back 68

impact cratering
volcanism
tectonics
erosion

Front 69

what causes the aurora?

Back 69

charged particles of the magnetosphere

Front 70

outgassing

Back 70

process by which volcanic eruptions release its gas into the atomsphere.

explains earths atmosphere and oceans.

Front 71

what causes tectonic forces?

Back 71

convection of the mantle.


compression forces -> mountains
pulling -> valleys

Front 72

what are greenhouse gases

Back 72

gases that are good at absorbing infrared light

Front 73

Why did Mars change?

Back 73

Mars’s atmosphere must have once been much thicker for its greenhouse effect to allow liquid water on the surface.
Somehow Mars lost most of its atmosphere, perhaps because of a declining magnetic field.

Front 74

does venus have plate tectonics?

Back 74

probably not.

Front 75

why is venus so hot?

Back 75

greenhouse effect.

-thick carbon dioxide atmosphere.

Front 76

why does venus have so little water?

Back 76

the runway greenhouse effect.


-heat causes evaporation, which causes more water vapor to be trapped in the atmosphere. the water vapor is a greenhouse gas and in turn causes more heat. which causes more evaporation ...

Front 77

carbon dioxide cycle

Back 77

Atmospheric CO2 dissolves in rainwater.

Rain erodes minerals that flow into the ocean.

Minerals combine with carbon to make rocks on ocean floor.

Front 78

what features of earth are important for life?

Back 78

surface liquid water, atmospheric oxygen, plate tectonics, climate stability

Front 79

What makes a planet habitable?

Back 79

Located at an optimal distance from the Sun for liquid water to exist

Large enough for geological activity to release and retain water and atmosphere

Front 80

What are jupiter and saturn made of?

Back 80

Jupiter and Saturn
Mostly H and He gas

Front 81

what are neptune and uranus made of?

Back 81

Uranus and Neptune
Mostly hydrogen compounds: water (H2O), methane (CH4), ammonia (NH3)
Some H, He, and rock