Final (Comprehensive) Flashcards
What is our cosmic address?
Earth, solar system, Milky Way Galaxy, local group, local supercluster, Universe
The start of the Universe’s expansion is commonly called ___ ___ ____.
The Big Bang
The farther away we look in the ____, the farther back we look in ____.
distance; time
Lightyears
The distance light can travel in one year
According to the Voyage Model, if the Sun was a grapefruit, the Earth would be a ____ ______. Jupiter would be a _____.
pen’s ballpoint; marble
The nearest star to the Sun is __ light years away.
4
If a light year is 1 mm, the Milky Way is the length of a _____ _____.
football field
If the time span between the Big Bang and now were a calendar, when would humans be?
Last 30 seconds of December 31
Earth’s daily rotation is…
how it spins on its axis
Earth’s orbit around the Sun is a _____.
revolution
Earth’s average orbital distance is equal to
1 au (astronomical unit)
1 au =
150 million km
Earth’s orbital path defines a flat plane called an ____ ____.
ecliptic plane
Does the solar system move in relation to other stars?
Yes
How fast does the solar system move in relation to other stars?
70,000 km per hour40,000 mph
Virtually, every galaxy outside the Local Group is moving ____ us.
away from
Who developed the first scientific model for astronomy?
Ancient Greeks
All scientific models are subject to being _____.
disproved
Always change the ____ rather than the ____.
model; data
A scientific model requires what 3 things?
Geometry, Physics, Aesthetics
What are the 5 steps of a scientific model?
“Real World” -> observe nature -> Model (geometry, physics, aesthetics) -> comparative observations -> revise model to match observations
Does a scientific model require accuracy to qualify as a model?
No
What type of universe did Ptolemy believe in?
Ptolemaic System: geocentric
Did the Ptolemaic System qualify as a scientific model? Was it accurate?
Yes; No
uniform circular motion
Move in a circle at a non-varying speed
Aristotelian Physics
The natural motion of all earthy materials is to fall towards the center of the universe (Earth)
What are the four earthy materials in Aristotelian Physics?
Earth, air, fire, water
According to Aristotelian Physics, what are the planets/heavenly bodies made of?
The 5th material, quintessence
Greeks were obsessed with perfect _____ and _____.
circles; spheres
What three things supported the Ptolemaic System?
uniform circular motion, Aristotelian Physics, Greek love of perfect circles and spheres
Greeks believed the heavenly bodies had no ____.
blemishes
Copernicus proposed a ____ model for the universe.
heliocentric
What did Copernicus believe orbited the earth?
Just the moon
What was the Copernican System’s primary motivation?
Aesthetics
Was the Copernican System more accurate than the Ptolemaic System? Why or why not?
No. Held flawed belief in uniform circular motion.
Did the Copernican System qualify as a scientific model?
No, there was no physics aspect.
What was the geometry aspect of the Copernican System?
uniform circular motion
Was the Copernican System a better or worse scientific model than the Ptolemaic System?
worse
What did Tycho Brahe contribute to astronomy?
astonishingly accurate naked-eye observations
How were Tycho’s observations so accurate?
he had a giant angle-measurer
How accurate were Tycho’s observations?
within an arcminute
What is an arcminute?
1/60 of a degree
Did Tycho side with Ptolemy or Copernicus?
Ptolemy
Tycho’s data allowed people to _______________.
test the Ptolemaic and Copernican models
What did Galileo contribute to astronomy?
he invented a stronger telescope
Galileo began the process of finding _____ to satisfy the Copernican System.
physics
What made Kepler a better scientist than those before him?
He tossed out ideas if they didn’t fit the model or agree with the data.
Kepler tossed out ideas if they didn’t fit the ____ or agree with the ____.
model; data
Kepler was _____’s apprentice.
Tycho
Did Kepler like the Ptolemaic or Copernican System?
Copernican
What did Kepler discover?
elliptical orbits
Kepler changed the ____ to fit the ____.
model; data
What is an example of Kepler changing the model to fit the data?
He substituted an ellipse for a circle in regards to orbits.
What is Kepler’s first Law of Planetary Motion?
Planets orbit the Sun in elliptical orbits with the sun at one focus.
What is Kepler’s second Law of Planetary Motion?
As a planet orbits the Sun, its distance from the Sun changes. If it’s closer to the Sun, it moves faster. If it’s farther from the Sun, it moves slower.
According to Kepler’s second law, planets move faster when they are _____ ____ the Sun.
closer to
According to Kepler’s second law, planets move slower when they are _____ ____ the Sun.
farther from
What is Kepler’s third Law of Planetary Motion?
There is a mathematical relation between a planet’s period (time it takes to orbit Sun) and its distance from the Sun.p^2 = K * a^3More distant planets orbit the Sun at slower average speeds, obeying the precise mathematical relationshipp^2 = a^3
In p^2 = K * a^3, what is p?
p = period
In p^2 = K * a^3, what is K?
K involves the mass of the Sunwith right units, K = 1, rendering it unnecessary in the equationp^2 = a^3
In p^2 = K * a^3, what is a?
a = distance between the Sun and the planetmeasured in au (astronomical units)
p^2 = K * a^3 can be used to determine the ____ of stars.
mass
Kepler’s third law is the only way we have of measuring the ____ of faraway space objects.
mass
How did Kepler’s model involve physics?
magnetic force between Sun and planets (incorrect)
How did Kepler’s model involve geometry?
ellipses
Isaac Newton built on _____’s model and _____’s data.
Kepler; Galileo
What does Newtonian Physics include?
Three Laws of Motion and Law of Gravity
Newton’s telescopes used ____ instead of lenses.
mirrors
Newton invented what mathematical discipline?
calculus
Newton’s Three Laws of Motion ____ (prove/disprove) Kepler’s Laws.
prove
Newton’s Laws explain the movement of ____.
planets or heavenly bodies
What is Newton’s first law?
Inertia. Every body continues in its state of rest or uniform motion in a straight line unless an external force acts. An object at rest tends to stay at rest, while an object in motion tends to stay in motion.
Velocity includes ____ while speed does not.
direction
acceleration
any change in velocity (speeding up, slowing down, changing direction)
A negative acceleration is _____ ____.
slowing down
A positive acceleration is ____ ____.
speeding up
G-force happens when you’re in something accelerating ____.
positively
Inertia happens when you’re in something accelerating ____.
negatively
What is the difference between G-force and inertia?
G-force: positive accelerationInertia: negative acceleration
In order to accelerate an object, you must apply __ _____ ____.
an external force
Applying a perpendicular external force to an object changes ____.
velocity
Applying a parallel external force to an object changes ____.
speed
To change an object’s velocity, you must apply a _____ _____ force.
perpendicular external
To change an object’s speed, you must apply a _____ _____ force.
parallel external
When applying the same force, more massive objects accelerate ____ and less massive objects accelerate ____.
less; more
What is Newton’s second law?
force = m*aforce = mass * acceleration
The rate of change of momentum of a body is proportional to ____ ______ ______.
the applied force
The rate of change of momentum of a body takes place in the direction ___ _____ _____.
the forces takes
What is Newton’s third law?
To every action, there is an equal and opposite reaction.
What is the reaction of Earth’s gravity pulling you down toward its center?
you pull the Earth up with the same amount of force
What is an example of an action/reaction pair?
you/EarthEarth/Sun
action = ?
action = change of momentum * distance over which momentum is changed
Earth pulls you down and you pull Earth up with a force equal to ____ ____.
your weight
Explain the fuel/rocket action/reaction pair.
The built up fuel pressure pushes out back of rocket, thrusting rocket up.
What is Newton’s Law of Universal Gravitation?
There is a force of gravitation between any 2 objects in the universe. More massive objects have a greater gravitational force.Force = G * [Mass(1) * Mass(2)] / (Distance)^2
_____ is also a factor in Newton’s Law of Universal Gravitation.
Distance
radius
the distance to the center
Give an example of distance being a factor in Newton’s Law of Universal Gravitation.
You -> EarthEarth -> Sun
Where should you measure the distance between two objects from?
their centersex.: Earth’s center -> your bellybutton
In Force = G * [Mass(1) * Mass(2)] / (Distance)^2, what is G?
gravitational constant
In Force = G * [Mass(1) * Mass(2)] / (Distance)^2, what is the distance?
between the two objects’ centers
Why don’t you fall toward other objects if there’s a gravitational force between you?
The gravitational force between you and the Earth is greater, because Earth has a greater mass than any object on it. Earth pulls you down.
If the distance between two objects doubles, there’s ____ the force.
1/4
If the distance between two objects triples, there’s ____ the force.
1/9
If the distance between two objects is 10 times, there’s ____ the force.
1/100
If an object weighs 100 N, and its distance from Earth doubles, what does it weigh now?
25 N (Newts)
The moon is basically ____.
falling
The more massive object has more force acting on it, thus it takes ___ force to accelerate it.
more
Two objects orbiting the same object will have ___ orbital periods/speed/etc.
equal
In general, for anything to move in a circular path, you have to have an inward force that’s constantly applied for a change in direction. What is this force?
centripetal force
centripetal force
a force that acts on a body moving in a circular path and is directed toward the center around which the body is moving
When the moon orbits Earth, ____ applies the centripetal force.
gravity
If centripetal force suddenly stops, the object will…
go in a straight line (Newton’s first law, inertia)
Do things fall on the moon?
yes
What fraction do objects weigh on the moon compared to Earth?
1/6
While falling, an object is ____.
weightless
What two modifications have been made to Newton’s laws?
Quantum Mechanics (atoms do not obey Newton’s laws)Einstein’s Relativity
What is the Law of Conservation of Energy?
total amount of energy in the universe always remains the same
How does the Law of Conservation of Energy work?
different types of energy (gravitational, motion, etc) convert into one another
Does mass affect orbital periods?
No
What affects orbital periods?
orbital distance
eccentricity
amount an ellipse is stretched compared to a circle; circles have zero eccentricity
Why can we use Kepler’s third law to calculate a planet’s average orbital speed?
The law relates a planet’s orbital distance to its orbital time (period).
How did Galileo answer the aesthetic objection to a heliocentric system?
Using his telescope, he proved the existence of sun spots and mountains & valleys on the moon.
stellar parallax
apparent shifting of an object against a background; parallax depends on distance, nearer objects experience greater parallax than more distant objects
What is Occam’s Razor?
the idea that scientists prefer the simpler or more aesthetically pleasing of two otherwise equal models
spectroscopy
the study of the interaction between matter and radiated energy; the measurement of radiation intensity as a function of wavelength
What is light?
wave of something in the electric field and the magnetic field
electric field
makes electric forces work
magnetic field
makes magnetic forces work
Which two scientists worked together to form spectroscopy? What two tools did they use?
Kirkoff - spectroscopeBunsen - Bunsen burner
What did Kirkoff and Bunsen do?
They put various things in a Bunsen burner and watched through a spectroscope.
What two fields oscillate back and forth to make a wave? How so?
magnetic and electriclarge positive > zero > large negative > zero > large positive > zero > large negative > zero…
What color has the longest wavelength?
red
What color has the shortest wavelength?
blue/violet
What are the characteristics of a red wave? (wavelength, frequency, energy)
long wavelength, low frequency, less energy
What are the characteristics of a blue wave? (wavelength, frequency, energy)
short wavelength, high frequency, more energy
frequency
number of times per second that a wave hits youlonger waves hit less often; shorter waves hit more often
Frequency is measured in ____.
Hertz
high frequency = ____ energy
more
low frequency = ____ energy
less
What are the characteristics of radio waves? (wavelength, frequency, energy)
long wavelength, low frequency, less energy
What are the characteristics of gamma waves? (wavelength, frequency, energy)
short wavelength, high frequency, more energy
How much energy do ultraviolet waves produce in relation to other waves?
a lot (hence sunburns), more than infrared but less than gamma rays
In modern astronomy, how much of the electromagnetic spectrum is used?
all
The formation of the three types of spectra are addressed in ____ Rules.
Kirkoff’s
What are the three types of spectra?
continuous, emission/bright line, absorption/dark line
Describe continuous spectra.
like a full rainbow, no discontinuous or stark changes
Describe emission/bright line spectra.
does not emit light; bright, narrow lines of color; opposite of absorption
Describe absorption/dark line spectra.
opposite of emission; looks like a continuous spectrum with lines missing
What is Kirkoff’s first rule? (How is a continuous spectrum produced?)
A continuous spectrum is produced when you have hot solid, hot liquid, or hot compressed gas.ex. incandescent lightbulb; sun’s core
What is Kirkoff’s second rule? (How is an emission line spectrum produced?)
Emission line spectra are produced by hot thin gas. The wavelengths (colors) of the emission lines depend on the chemical compound.ex. Sodium burns yellow.
What is Kirkoff’s third rule? (How is an absorption line spectrum produced?)
You must have a continuous spectrum first passed through a cool (lower temperature than whatever caused the continuous spectrum) thin gas. Wavelengths reflect the composition of the cool thin gas not whatever caused the initial continuous spectrum.
The sun is hotter in its ___ than its ____ ____.
core; outer atmosphere
What is the spectral result of the sun’s core being hotter than its outer atmosphere?
The core is the continuous spectrum source and the outer atmosphere provides a cool thin gas to create an absorption spectrum.
You must have a ____ spectrum before you can have an absorption line spectrum.
continuous
Can you tell what element is involved by the continuous spectrum?
no
Who figured out the structure of the atom?
Neils Bohr
What did Bohr determine about atoms in relation to element identification?
The number of protons in an atom’s nucleus determines the element.
Electrons orbit the ____ at different levels.
nucleus
Can an electron orbit the nucleus between levels?
no
Can an electron jump from one orbital level to another?
yes
To jump from a lower level to a higher level, an electron needs more ____.
energy
Where does an electron obtain the energy needed to jump to higher levels?
the electron absorbs photons of light
What type of spectrum is produced when an electron jumps to a higher level? Why?
absorption line spectrumthe photon/wavelength of light disappears because it was absorbed by the electron
What type of spectrum is produced when an electron jumps down a level? Why?
emission line spectrumWhen it jumps down, it emits a wavelength of light and releases energy.
In what direction is the light from an electron emitted?
randomnot necessarily in the same direction it was absorbed from
Every element has its own unique set of ___ levels.
energy
Each element emits and absorbs a different amount of ___.
energy
The Doppler effect applies to ___ and ____.
sound; light
Doppler effect
higher pitch means it is moving toward you; lower pitch means it is moving away from you
What are the characteristics of a high pitch sound? (frequency, wavelength)
higher frequency, shorter wavelength
What are the characteristics of a low pitch sound? (frequency, wavelength)
lower frequency, longer wavelength
What happens during a blueshift?
whole pattern shifted toward shorter wavelengths
What happens during a redshift?
whole pattern shifted toward longer wavelengths
Closer stars’ spectral patterns are shifted towards ___.
blueThis is not enough to actually affect the color of the star.
Farther stars’ spectral patterns are shifted towards ___.
redThis is not enough to actually affect the color of the star.
Why are telescopes placed on mountaintops?
to be above the atmosphereless light pollution
What are the three function of an astronomer’s telescope?
1- Light gathering power2- Resolving power3- Magnifying power
What is the least important function of a telescope?
magnifying power
What is the most important function of a telescope?
light gathering power
Telescopes: ____ power is not worth it if you do not have good ____ and ____ power.
Magnifying power is not worth it if you do not have good resolving and light gathering power.Before you get a large image, you must first have a quality image.
resolving power
image claritygood- sharpbad- fuzzysecond most important telescope function
light gathering power
allowance to gather or collect light to view faint/faraway objectsmost important telescope function
What determines the magnifying power of a telescope?
focal length or eyepiece
Resolving power is determined by the main ____ or ___.
mirror; lens
If a telescope’s lens is doubled in diameter, you can see things that are ___ as big.
half
Lens diameter is directly related to…
what size objects you can see
If a telescope’s lens diameter is increased more than about 20 inches, the resolving power is determined by ____ _____.
Earth’s atmosphere
How does the Hubble telescope achieve better resolving power?
It is positioned above Earth’s atmosphere.
What is the formula for the area of a circle?
πr^2
Telescopes are like funnels in order to…
collect more light
If you double the diameter, the area increases by ___.
4
The light gathering power of a telescope depends on the….
square of the diameter
Resolving power depends on the ____.
diameter (of the main lens)
The diameter of the main mirror/lens determines the ____ ____ power and the ____ power.
light gathering; resolving
Lenses ____ and mirrors _____.
Lenses refract and mirrors reflect.
Refracting telescopes use ____ lenses.
convex (curves outward, as opposed to concave)
refract
light bends
focal length
distance from lens to focal point (eyepiece)
Formula: magnifying power =
focal length / distance to object
If a lens is heavy, it will…
sag or curve
What are the 2 primary disadvantages of a refracting telescope?
1- Limit to how big you can make them2- Very expensive
What are the 2 types of reflecting telescopes?
Newtonian DesignCassegrain Design
What are the 2 main features of a reflecting telescope?
eyepieceprime focus configuration
What are 2 benefits of a reflecting telescope?
very large telescopeputs astronomer at eyepiece
Describe a Newtonian Design telescope.
low cost, cheap, good qualityhas secondary mirror
Describe a Cassegrain Design telescope.
eyepiece at bottom for ease of use
What is the most common type of large telescope?
Cassegrain Desgin
Describe a Schmidt Cassegrain telescope.
a little more expensive (than Cassegrain), better image quality, correcting lens
What is the structure of a refracting telescope?
Rays from distant point source=======>LENS—(focal length)—>eyepiece (focal point)
Studying the sun helps us understand ____ ___.
other stars
The mass of a star can be determined using what?
Kepler’s 3rd law (as modified by Newton)planets orbiting the star or binary system orbits
Many stars are in ___ orbits.
binary (2 stars orbiting each other)
A star’s energy output depends on ___ and ____.
temperature; distance
What is the formula to determine the surface area of a sphere?
4πr^2
To determine a star’s energy output, you must know…
how bright it appears to be and distance
Luminosity is measured in…
watts (Joules per second)
luminosity
how much energy is put out per second
What is the sun’s energy output?
3.8 * 10^26
A red star is ___ than a blue star.
cooler
A star’s colors tells us its approximate ____.
temperature
Where a star’s brightness peaks (on the color spectrum) is directly related to ___ and nothing else.
temperature
How does the sun get its energy?
nuclear fusion
How hot is the sun?
6000º K
E=mc^2
energy = mass * (speed of light)^2
In Einstein’s E=mc^2, ____ and ____ are interchangeable.
energy; mass
What is the speed of light?
186000 miles per second3 * 10^8 meters per second
nuclear fission
something (such as heavy elements or heavy atoms) splitting and releasing energy
What is the sun’s composition?
98% H and He2% every other element
nuclear fusion
lighter elements combing to make heavier elements
The sun, at its start, had enough H fuel to last ___ years. It has ___ years left.
10 billion; 5 billion
What is the process of the sun’s nuclear fusion?
4 H atoms make 1 He atomthat difference in mass is converted to energy according to E=mc^2High density forces repel protons together
Where do the sun’s nuclear fusion reactions take place?
in the core
What is the purpose of a convection current on the sun?
transfers heat to its surface
Sun: granules
bubbles from convection currents
Sun: corona
very thin gas only visible during solar eclipse
What are the four parts/layers of the sun?
core, photosphere, chromosphere, corona
Who discovered sunspots? When?
Galileo; 1610
sunspots
areas of sun that are a little coolerwhere convection currents are not going or where energy is passing over
Sunspots have very strong ___ fields.
magnetic
Sunspots deflect ___ currents.
convection
Different colored areas of the sun indicate a difference in ___.
temperature
solar flare
brighter regions of the sun
Sunspots and solar flares are directly related to the sun’s ___ field.
magnetic
When sunspots and solar flares are present, the sun is ___.
active
How long is a solar activity cycle?
about 11 years
solar minimum
few sunspots or solar flaresslightly lower luminosity
solar maximum
lots of sunspots or solar flaresslightly higher luminosity
Describe a solar activity cycle.
(1-4 years) solar minimum -> (next 5-11 years) solar maximum -> (next 1-4 years) solar minimum -> (next 5-11 years) solar maximum -> (next 1-4 years) solar minimum…
coronal mass ejections
material flying out of suncould interact with Earth’s magnetic field