Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
94 Cards in this Set
- Front
- Back
|
Large scale structure of universe (smallest to largest)
|
1. solar system
2. solar neighborhood 3. (Milky Way) galaxy 4. local group 5. local supercluster 6. universe at large |
|
|
what is the sun's nearest neighbor star
|
proxima centauri
|
|
|
most distant planet
|
neptune
|
|
|
how old is the solar system?
|
4.5 billion years old
|
|
|
how old is the universe?
|
14 billion years old
|
|
|
If the sun was the size of a ping pong ball, how far away would Neptune be?
|
500 ft away
|
|
|
If the sun was the size of a ping pong ball, how far away would the nearest star be?
|
700 mi away
|
|
|
Stars
|
-almost all visible matter of universe inside stars
-building blocks of larger astronomical systems |
|
|
Solar Neighborhood
|
-the "sea" of stars closest to the sun (within a few hundred ly)
-several 10s of 1000s of stars SO... -solar system very isolated from other stars -space empty of stars |
|
|
Galaxy
|
-large group of billions of stars
|
|
|
What is the name of our galaxy?
|
Milky Way Galaxy
|
|
|
What is the shape of Milky Way?
|
-spiral shape, flattened with central bulge (like fried egg)
|
|
|
Where is the solar system located in the Milky Way?
|
-the disk, far from the nucleus
|
|
|
If Neptune's orbit is the diameter of a ping pong ball, what is the diameter of a galaxy?
|
2000 miles
|
|
|
The Local Group
|
-group of about 50 galaxies
--ours --Andromeda |
|
|
If the diameter of the galaxy is the size of a ping pong ball, how close is Andromeda?
|
3 ft
all galaxies in Local Group fill volume of about 4 ft in diameter |
|
|
Virgo Cluster
|
-several thousand galaxies
-40 million ly away |
|
|
Local Supercluster
|
-10 galaxy clusters
-Local Group -Virgo Cluster |
|
|
What conclusion can be drawn from the fact that the light of stars in the nighttime sky is concentrated around the Milky Way Galaxy?
|
it is relatively flat
|
|
|
About how long would light take to travel from the center of our galaxy to the position of the solar system?
|
30,000 years
|
|
|
Time & Distance
|
-more distant objects are seen further back in time
-study of distant objects tells us DIRECTLY about the universe long ago |
|
|
Suppose a star explodes that's located 4000 ly away. If the explosion was observed on Earth in 1000 AD, when did the star actually explode?
|
3000 BC
|
|
|
Elementary particles
|
-no intrinsic size
-no internal structure -properties include mass and electric charge -12 types: 6 quarks, 6 leptons |
|
|
Quarks
|
-up
-down -have relatively high mass |
|
|
Lepton
|
-electron
-little or no mass |
|
|
Baryon
|
-3 quarks
-proton (2 up, 1 down) -neutron (1 up, 2 down) |
|
|
Atomic Nuclei
|
at least one proton and maybe neutrons
|
|
|
Atomic Number
|
-Z
-number of protons |
|
|
Atomic Mass Number
|
-A
-number of protons + neutrons |
|
|
What is the most fundamental difference between a nucleus of hydrogen and a nucleus of helium?
|
-hydrogen has 1 proton, helium has 2
-# of protons uniquely identifies an element |
|
|
Which elementary particle (of those that make up matter) is least massive?
|
electron
|
|
|
Protons and neutrons are examples of ______
|
baryons
|
|
|
How many protons and neutrons in 12C nucleus?
|
6 protons
6 neutrons |
|
|
How many protons and neutrons in 13C nucleus?
|
6 protons
7 neutrons |
|
|
What do two isotopes of the same element always have in common?
|
number of protons
|
|
|
How do two isotopes of the same element differ?
|
number of neutrons
|
|
|
What is the chemical composition of the universe?
|
the proportion of various nuclei in the universe (mostly stars)
|
|
|
Atoms & Ions
|
each consists of an atomic nuclei and one or more electrons orbiting nucleus
|
|
|
Atom
|
# of electrons = # of protons
|
|
|
Ion
|
# of electrons doesn't = # of protons
|
|
|
Molecules
|
-each consists of 2 or more atoms
-rare in universe, common on Earth |
|
|
The atomic number of oxygen is 8. Therefore, an 18O atom contains how many neutrons and electrons?
|
10 neutrons
8 electrons (always same # of protons and electrons) |
|
|
What fundamental force of nature is responsible for holding together planets like the Earth and Saturn?
|
gravitational force
|
|
|
Gravitational Force
|
-attractive
-affects particles with mass -weak -planetary to cosmic |
|
|
Electromagnetic Force
|
-attravtive & repulsive
-affects particles with electric charge (+ or -) -strong -atomic to human |
|
|
Strong Force
|
-attractive
-affects quarks and baryons -strongest (over short distance) -atomic nuclei |
|
|
Gravity
|
-holds together planets and stars
-binds planets to the sun -holds together galaxies -holds together galaxy clusters |
|
|
Is EM force likely to be effective in binding together protons and neutrons in an atomic nucleus?
|
no, has no effect on neutrons and repels protons
|
|
|
Is the gravitational force likely to be effective in binding together protons and neutrons in an atomic nucleus?
|
no, EM force of repulsion is stronger
|
|
|
What fundamental force of nature is responsible for the mechanical strength of a concrete block?
|
electromagnetic
|
|
|
What force is responsible for all large scale (astronomical) structures in the universe?
|
gravitational
|
|
|
What force(s) affect(s) neutrons?
|
strong and gravitational
|
|
|
Light
|
-provides almost all info we have about universe
-travels through near vacuum of interplanetary space -reaches us in 8 mins |
|
|
Properties of light
|
-carries energy
-travels fast (186,000 mi/sec) -can travel through a vacuum |
|
|
Wave model
|
beam of light is a continuous train of waves of EM force
|
|
|
Photon model
|
-beam of light is a stream of massless "particles" called photons
-photons travel at the speed of light |
|
|
Wavelength
|
-λ
-distance between wave crests |
|
|
Frequency
|
# of waves passing fixed point/sec
|
|
|
Wave speed
|
-c
-speed of a given wave crest |
|
|
Which particle is affected by all three fundamental forces?
|
proton
|
|
|
If wavelength is 3 ft and frequency is 4 waves/sec, how fast is it traveling?
|
12 ft/sec
|
|
|
wave speed formula
|
λ x f=c
|
|
|
Properties of wavelength
|
-longer wavelength means lower frequency
-shorter wavelength means higher frequency |
|
|
photon energy formula
|
Eph=hxf
or Eph=hx(c/λ) |
|
|
Red
|
-longest wavelength
-lowest frequency -lowest energy per photon |
|
|
Blue
|
-shortest wavelength
-highest frequency -highest energy per photon |
|
|
Which carries more total energy (red/blue) per beam of light?
|
depends on # of photons in each beam
|
|
|
The full range of EM radiation (longest wavelength to shortest)
|
-light is only one type
1. radio 2. infrared 3. (visible) light 4. UV 5. x-rays 6. gamma-rays |
|
|
If a sound wave has a wavelength of 4 ft and a frequency of 300 waves per second, what is the speed in ft/sec?
|
1200 ft/sec
|
|
|
According to the photon model of light, how fast does a photon travel?
|
186,000 mi/sec
|
|
|
Which term refers to EM radiation having the highest frequency?
|
gamma rays
|
|
|
Brightness
|
-amount of energy from a light source falling on each square cm, each second at location of observer
-ergs per square cm/sec |
|
|
Luminosity
|
-amount of energy a light source emits each second in all directions
-ergs/sec -watts |
|
|
What is an intrinsic property of a light source?
|
luminosity
|
|
|
How does brightness decrease from one unit to two units of distance away from a light source?
|
1/4 as much
|
|
|
If you move from 2 ft to 10 ft away from a light source, how does the brightness change?
|
1/25
|
|
|
How are brightness and luminosity related?
|
brightness is DIRECTLY PROPORTIONAL to its luminosity
|
|
|
How are brightness and distance related?
|
brightness is INVERSELY PROPORTIONAL to the SQUARE of its distance
|
|
|
If 10 gallons of gas cost $30, how much do 20 gallons cost?
|
-$60
-directly proportional |
|
|
If you drive 80 mi at 40 mph, how long does it take?
|
-2 hours
-inversely proportional |
|
|
If two stars are at the same distance, but star A is 3x more luminous, which star is brighter? By how many times?
|
A, by 3x
|
|
|
If two stars have the same luminosity, but star A is 3x more distant, which is brighter? By how many times?
|
B, by 9x
|
|
|
If the distance between you and a light source increases, from 2 to 8 meters, the brightness becomes ____ as much
|
1/16
|
|
|
What happens to the heating element of an electric oven when you turn the oven up?
|
-luminosity increases
-color shifts from deep red to orange (shorter λ) |
|
|
EM radiation from "hot" objects
|
all objects (even cold ones) emit EM radiation
|
|
|
Gas
|
-each particle moves about randomly, often colliding with its neighbors
-each gas particle has kinetic energy (some have more/less at any given moment) |
|
|
Temperature
|
-measure of the AVERAGE kinetic energy of EACH gas particle
-high T doesn't necessarily mean lots of heat -in Earth's upper atmosphere T is high, but few gas particles |
|
|
Absolute zero
|
-temp at which particles have no kinetic energy
-lowest possible temp -0 on Kelvin scale |
|
|
Heat
|
-measure of the TOTAL kinetic energy of ALL particles in a volume
|
|
|
How is light emitted in an incandescent lamp?
|
by a filament (piece of wire heated by electric current)
|
|
|
As electric current and filament temperature increase...
|
1. luminosity increases dramatically
2. color shifts from deep red to orange |
|
|
Stefan-Boltzmann Law
|
L=σAT^4
L=luminosity (ergs/sec) A=surface area of emitting object (cm^2) T=temp (K) σ=constant (5.7x10^-5) |
|
|
If T doubled, by what factor does L increase?
|
16
2^4 |
|
|
If T tripled, by what factor does L increase?
|
81
3^4 |
