Astronomy Review Questions

Front 1

Define astronomical unit and light year.

Back 1

An astronomical unit is the average distance between the earth and the sun, and it is equivalent to about 150 million kilometers. A light year is the distance that light can travel in 1 year, which is about 10 trillion kilometers. We commonly use AU's to describe distances within our solar system, and light-years to describe distances of stars and galaxies.

Front 2

Explain the statement "The farther away we look in distance, the farther back we look in time."

Back 2

The farther away an object in space is from us, the longer it takes from the light from that object to reach us. For example, when we view an object that is 1 million light years away, we are seeing as it looked 1 million years ago, because that is how long it took for it's light (and thus it's image) to reach us.

Front 3

In what sense are we "star stuff?"

Back 3

Most of the material that we and our planet are made up of was created inside stars that lived and died before the birth of our sun.

Front 4

Briefly explain the Earth's daily rotation and annual orbit, defining the terms ecliptic plane and axis tilt?

Back 4

The earth rotates once around it's axis once each day, and it orbits around the sun once each year. The ecliptic plane is the path that the earth travels around the sun, and it is shaped like an ellipse. The axis tilt of the earth is 23.5 degrees. In space, there is no direction, so the tilt only makes sense in relation to the ecliptic plane.

Front 5

What are circumpolar stars? Are more stars circumpolar at the the North Pole or in the United States?

Back 5

Circumpolar stars are located near the north celestial pole, meaning that they remain perpetually above the horizon, circling around the north celestial pole each day. There are more circumpolar stars at the North Pole than in the United States.

Front 6

Suppose Earth's axis had no tilt. Would we still have seasons? Why or why not?

Back 6

We would not have seasons if the Earth's axis had no tilt. This is because the season's of earth are caused by the earth's tilt, resulting in varying levels of direct sunlight.

Front 7

Briefly describe the moon's cycle of phases. Can you ever see a full moon at noon? Explain.

Back 7

The moon goes through the following phases: new moon > waxing crescent > first quarter > Waxing Gibbous > Full Moon > Waning Gibbous > Third Quarter > Waning Crescent > and back to New Moon. A full moon is not visible at noon because it is highest in the sky around midnight.

Front 8

Why do we always see the same face of the moon?

Back 8

The moon rotates on it's axis in about the same amount of time it takes for it to orbit the earth, a trait referred to as synchronous rotation.

Front 9

What do we mean by a model in science?

Back 9

A model is a conceptual representation created to explain and predict observed phenomena.

Front 10

What is an ellipse. Define it's foci, semimajor axis, an eccentricity.

Back 10

An ellipse is a special type of oval that planetary orbits follow. Often 2 tacks are used to help draw an ellipse, and the foci are the 2 areas where the tacks were located. The semimajor axis is half of the major axis, which is equivalent to the long axis of the ellipse. The eccentricity describes how much an ellipse deviates from a perfect circle.

Front 11

Describe the three hallmarks of science and how we can see them in the Copernican revolution. What is Occam's razor? Why doesn't science accept personal testimony as evidence?

Back 11

1. Modern science seeks explanations for observed phenomena that rely solely on natural causes.
2. Science progresses through the creation and testing of models of nature that explain the observations as simply as possible.
3. A scientific model must make testable predictions about natural phenomena that will force us to revise or abandon the model if the predictions do not agree with observations.
The first showed up in the way Tycho's measurements of planetary motion caused Kepler to better explain those motions.
The second showed up in the way that several different models of the solar system were created and tested.
The third third shows up in the fact that several of the models could predict the motion of celestial bodies.
Occam's razor is the idea that scientists should agree with the most simple model available that agrees with observations.
Personal testimony can not always be verified.

Front 12

What is the difference between a hypothesis and a theory in science?

Back 12

A hypothesis is an educated guess, while a theory has survived repeated and varied testing.

Front 13

State Newton's three laws of motion. For each law, give an example of its application.

Back 13

1. An object moves at constant velocity unless a force acts to change its speed or direction.
Example: A car driving down the Lloyd is hit by a truck. The trucks impact forces the car into a ditch.
2. Force is equal to mass times acceleration.
Example: It requires less force to push a shopping cart that is filled with items than an empty shopping cart.
3. For every force, there is always an equal and opposite reaction.
Example: When you paddle a boat, you push the water and the water also pushes you.

Front 14

Define temperature and thermal energy. How are they related? How are they different?

Back 14

Temperature is the average kinetic energy of an object, while thermal energy measures the total kinetic energy of the particles. They are both forms of energy. They are different in that thermal energy relies on the density of particles as well as the temperature.

Front 15

Summarize the universal law of gravitation both in words and with an equation.

Back 15

Every mass attracts every other mass through the force called gravity. The amount of attraction between two objects depends upon the mass of the objects. The farther away objects are from each other, the less gravitational pull they will have on each other. Fg= G (M1M2/d2)

Front 16

Explain how the moon creates tides on Earth. Why do we have two high and low tides each day? How do the tides vary with the phase of the moon?

Back 16

Differences in gravitational attraction between the earth and the moon creates a tidal force that stretches the entire Earth to create 2 tidal bulges, one facing the moon and one opposite the moon. The high tides occur in the areas directly facing and the farthest away from the moon, and the low tides occur a quarter of the direction around the earth from both sides of the elliptic of the moon. When the moon is farther away from us in it's elliptic, there is less gravitational pull.

Front 17

What are the four major ways light and matter can interact? Give an example of each from everyday life.

Back 17

1. Emission. Example: A light bulb emits light.
2. Absorption. Example: When you place your hand near a light bulb, your hand absorbs some of the energy, which warms your hand.
3. Transmission. Example: Sunlight passes through a clear glass window.
4. Reflection. Example: Light reflecting off of a mirror.

Front 18

List the different forms of light in order from lowest to highest energy. Would the list be different if you went in order from lowest to highest frequency? From Shortest to longest wavelength? Explain.

Back 18

Radio Waves > Microwaves > Infrared > Visible Light > Ultraviolet > X rays > Gamma Ray. The frequency would be in the same order, while the wavelength would be in a reverse order. Frequency determines energy, and lower wavelengths correspond with higher frequency and energy.

Front 19

What determines an atom's atomic number? What determines its atomic mass number? Under what conditions are two atoms different isotopes of the same element? What is a molecule?

Back 19

An atom's atomic number is determined by the number of protons. The atomic mass number is determined by the mass of the protons and neutrons. Isotopes occur when there is the same number of protons, but a different number of neutrons, which would give it a different mass but the same atomic number. A molecule is when atoms of the same element combine.

Front 20

Describe the Doppler effect for light and what we can learn from it. What does it mean to say that radio waves are blueshifted? Why does the Doppler effect widen the spectral lines of rotating objects?

Back 20

The Doppler effect causes shifts in the wavelengths of light, and it can help us to determine the motion of distant objects relative to us. Blue-shifted radio waves means the object is moving towards us. The Doppler effect widens the spectral lines of rotating objects because the wavelengths changes from blue or red.

Front 21

How many galaxies are in the universe?

Back 21

about 100 billion

Front 22

Sizes (earth to universe)

Back 22

Earth > solar system > Milky Way > Local Group > Local Cluster > Universe

Front 23

Star

Back 23

ball of gas that generates heat and light through nuclear fusion

Front 24

Sun Grapefruit is equal to

Back 24

Earth Ballpoint

Front 25

Orion Nebula is an area where ______________ is being formed

Back 25

new stars

Front 26

How many stars are in our galaxy

Back 26

100 billion

Front 27

light year is equal to _______ not ________

Back 27

distance; time

Front 28

Across solar system to neptune

Back 28

60 AU

Front 29

Milky Way to Andromeda

Back 29

2.5 million ly

Front 30

a constellation is a ________ of the sky

Back 30

region

Front 31

how many constellations fill the entire sky

Back 31

88

Front 32

How old is earth

Back 32

4.5 billion years

Front 33

how many years for earth to go around milky way galaxy

Back 33

230 million years

Front 34

polaris is at ______ degrees

Back 34

40

Front 35

where does prime meridian run through

Back 35

greenwich, england

Front 36

the sky varies with ________ but not with _________

Back 36

latitude; longnitude

Front 37

the further away from the earth, the more ______ ______ the object has

Back 37

potential energy

Front 38

new moon and full moon cause what tides

Back 38

spring tide

Front 39

1st and 3rd quarter moon cause what tides

Back 39

neap

Front 40

why is the sunset red

Back 40

the angle limits blue light

Front 41

what are the black lights on the spectrum of the sun

Back 41

gases that absorb light

Front 42

measure the flow of energy in light in units of

Back 42

watts/ joules

Front 43

Names of the week

Back 43

Mon Moon
Tues Tiw (mars)
Wed Woden (mercury)
Thurs Thor (jupiter)
Fri Fria (venus)
satur saturn

Front 44

Eratosthenes

Back 44

worked at library of Alexandria in Egypt
knew the size of the earth

Front 45

stellar paralax

Back 45

The apparent change in the position of a nearby star when observed from Earth due to our planet's yearly orbit around the Sun.

Front 46

ptolemy

Back 46

predicted motion of planets very well. earth centered model. said planets made swirly motions around the earth which explained retrograde motion

Front 47

Copernicus

Back 47

aristarcus made sun centered model. later copernicus said the same thing, and people believed him. believed in circular motion around sun.

Front 48

Tycho Brahe

Back 48

had nose chopped off in dual. wore a metal nose. thought earth was at center of solar system, but thought other planets went around sun

Front 49

kepler

Back 49

worked under tycho brahe. figured out earth moved around sun in oval ellipse

Front 50

kepler's laws of planetary motion

Back 50

1. orbit of each planet around sun is an ellipse
2. as planet moves around its orbit, it sweeps out equal area in equal times
3. more distant planets orbit the sun at slower average speeds.

Front 51

keplers 3rd law equation

Back 51

p2 = a2

Front 52

galileo telescope

Back 52

did not invent it, but he improved it

Front 53

galileo theories

Back 53

showed objects would stay in motion unless acted upon, disproved heavenly perfection, explained stellar paralax.

Front 54

______ goes through same phases as moon

Back 54

venus

Front 55

who cast pope as simplicio

Back 55

galileo

Front 56

galileo named jupiters moons after?

Back 56

greek god jupiters lovers

Front 57

acceleration

Back 57

any change in velocity units of speed/ time (m/s 2nd)

Front 58

braking is?

Back 58

deceleration or negative acceleration

Front 59

heart energy is

Back 59

friction

Front 60

inertia =

Back 60

mass x velocity

Front 61

angular momentum conservation

Back 61

ballerina

Front 62

kinetic energy is

Back 62

motion

Front 63

radioactive energy is

Back 63

light

Front 64

potential energy is

Back 64

stored

Front 65

freezing point

Back 65

celsius 0
fahrenheit 32

Front 66

boiling point

Back 66

celsius 100
fahrenheit 212

Front 67

e=mc squared

Back 67

energy = mass x speed of light squared

Front 68

calculate gravitational pull at different distances

Back 68

Fg=G M1M2/ d2

Front 69

nothing can go faster than

Back 69

the speed of light

Front 70

frequency of which we can view light

Back 70

400-7 nanometers

Front 71

as train passes you, the frequency goes from

Back 71

high to low

Front 72

slow spinning objects gives off

Back 72

low intensity lines

Front 73

objects spinning fast has

Back 73

high intensity lines and a greater doppler effect