Previous tests Flashcards
Full Moon
Sun, Earth, Moon
New Moon (sun, moon, earth) -waxing crescent -first quarter -waxing gibbous Full Moon (sun, earth, moon) -waning gibbous -third quarter -waning crescent (light is right to left - so crescent on the left like a C - bc light is darkened right to left too)
What position would you expect to see the moon straight south at sunset?
first quarter
Which position would a total solar eclipse occur
New moon
Which position would moon be due south at 6 am?
third quarter
When the moon is at third quarter, how much of total surface of moon is illuminated directly by sun’s light?
1/2
Waxing gibbous looks like
right side is 3/4 covered - light moves right to left across moon - Dark C on left
What do we call the time from a 3rd quarter moon to the next 3rd quarter moon?
Synodic month
When we refer to something as sidereal it is with respect to what?
stars
By your watch (solar time) how long does it take the earth to make one rotation on its axis?
23 h 56 m
To be a partial lunar eclipse which of the following must be true
Moon passes through Penumbra, with only a part passing through umbra
As we watch the night sky on a single night the stars appear to move overall
East to west
Newton developed a general law described the physical attraction of two objects. Which of the following does not affect the gravitational force btwn the sun and earth?
Radius of earth (does not in ?)
- IS AFFECTED BY:
- —mass of earth, mass of sun, distance from the center the sun to the center of earth
Which of the following is the longest in terms of time?
Lunar or synodic month
-compared to solar day, sidereal day, sidereal month
How many times a year will the sun be directly overhead (at zenith) in Provo, Utah?
0
Holding a ball above ground and it is not moving it is
Potential energy
1 samuel 20:5 speaks of new moon. Which is description of new moon described in scriptures?
First thin crescent moon seen in the evening at twilight
Go out and see bright star Sirius rising over mountains at 10 pm. You wait two weeks and go out to look for sirius in night sky. Which describes position of sirius?
It rose at 9:04 pm
T/F planets orbit slower the further they are from the sun?
TRUE
T/F planets orbit slower the further they are from the sun?
TRUE
Which is highest energy photons in the entire electromagnetic spectrum
Gamma rays
If earth were to shrink to half its current radius, what would happen to the surface gravity (or the acceleration of earth’s surface?)
It would increase
Standing at Honolulu HI and its dark. The position of Honolulu on earth’s latitude is 21.3 N and longitude is 157.8 W - how high above the horizon is the north star?
21.3 degrees
Standing on surface of mars with telescope, which planet would show phases similar to the moon as i look at them through my telescope
Earth
If we saw hydrogen line in a stars spectra moving toward us, where would we expect to see the hydrogen alpha line in the spectra?
It would be moved to the blue by an amount based on the velocity approach
I have a telescope with a 5000 mm focal length for the objective lens - which eyepiece would I need to use to get a magnification of 200x?
5000/x = 200 = 25 mm
What is correct order of electromagnetic spectrum from SHORT to LONG wavelenghts
gamma-rays, X-rays, ultraviolet, visible light, microwave, radio wave
Which has longest wavelength in the visible part of the electromagnetic spectrum?
Red light
How long does it take a planet to go through retrograde motion?
few months
What is cosmogony?
scientific study of the earth’s place in the universe
What is weight on moon compared to weight on earth? (gravitational acceleration is less on the moon)
weight on moon will be less than on earth
If Northern hemisphere is tipped toward sun, why would southern hemisphere have cooler weather?
tip means light is spread out over larger area due to lower angle - there are less hours of sunlight due to the tip
During total solar eclipse what is true?
moon is btwn earth and sun - NEW MOON
In provo the sun reaches its highest northern point in the sky on…
summer solstice
direction of velocity on a circle moving left…
toward the bottom of the page
direction of velocity on a circle moving left…
toward the bottom of the page
As we watch moon over a month we see diff. portions of the moon or phases. Why?
half the moon is always illuminated by the sun, but we see a diff fraction as the moon orbits the earth
Earth currently tipped 23.5 degrees. If something happened to increase the tip of the earth to 28 degrees, what would happen?
for latitudes like provo we would see hotter summers and cooler winters
diurnal motion is
nightly movement of the stars
I hold a ball 10 ft above the floor. Release ball and it accelerates toward the floor. Which is true?
As ball falls potential energy is converted to kinetic energy and the sum equals the original potential energy
We have telescope that uses mirrors to focus light. What is this?
Reflecting telescope
Absorption lines are formed when…
Photons are absorbed and cause an electron to move from a lower to higher energy state in the atom
in 1852 how was the calendar corrected
Pope Gregory XII caused 10 days to be dropped from 1852 and adjusted leap year
constellations visible in early evening change gradually over course of year due to…
revolution of earth about the sun
what is nature of light?
has properties of both particles and waves
what is sidereal day for earth?
23 h 56 m
What are Kepler’s laws of planetary motion
- orbit of every planet is an ellipse with sun at one focus
- line joining a planet and the sun sweeps out equal areas during equal intervals of time
- a^3 = p^2: wjere a is the semi-major axis and P is orbital period
Living on moon and watching earth what is true
Earth goes through phases, but they are opposite the moon phases as seen from earth
I look up into the sky and see a star appears yellow next to a red star. Why are they diff colors?
Yellow star is hotter than the red star and therefore gives off higher energy photon in the yellow region of the spectrum
To orbit earth’s surface an object must be going 17,000 mph. This would cause orbital period close to 90 min (once around earth). I want geosynchronous orbit (always above same location on earth). Where would this be?
btwn surface of earth and moon’s orbit
Constellations visible in early evening change gradually over course of year due to…
revolution of earth about the sun
constellations of zodiac most closely follow what line?
the ecliptic
sun reaches highest northern point in the sky on…
summer solstice
If the ecliptic and celestial equator matched (no tilt) what would happen?
we would have no seasonal changes
Suppose length of year was actually 365.2 days instead of 365.25 days. How often would we have leap year?
Every 5 years
T/F the only thing that impacts seasons is the earth’s tilt
FALSE
T/F an annular eclipse can only happen when moon is at apogee (furthest point from earth)
TRUE
T/F human eye can see majority of electromagnetic spectrum, but not all of it
FALSE
T/F we are standing on the roof of the ESC and see a star rise in NE. It will set in SW
FALSE
T/F a total solar eclipse can only happen when moon is at new moon
TRUE
T/F moon does not rotate on its own axis, we always see same face
FALSE
T/F phases of moon are caused by shadow of the earth
FALSE
T/F solar and lunar eclipses happen when moon is on the line of nodes
TRUE
T/F light travels from one place to another instantaneously
FALSE
T/F we can always apply modern astronomical definitions to scriptural references
FALSE
T/F according to Gregorian calendaring system 1600 was a leap year
TRUE
T/F a larger fraction of earth can see total lunar eclipse than can see a total solar eclipse
TRUE
T/F if i measure a redshift in a photon it means the object emitting that photon is moving away from me
TRUE
T/F if i measure a redshift in a photon it means the object emitting that photon is moving away from me
TRUE
Meridian
Line running from north, through zenith, to the south
Vernal equinox
Point where celestial equator and ecliptic cross, with sun going from south to north
opposition
point where planet is directly opposite sun from earth’s point of view
Ecliptic
path of sun through the stars over the course of a year
Zenith
point directly over your head
Elongation
Point where an inferior planet is as far away from the sun as it gets in the sky
Geocentric
model with earth as center
altitude
Height of a celestial object above the horizon
Jupiter’s moons
Ganymede, Europa, Lo
Uranus moons
Miranda, Juliet
Saturn moons
Enceledas, Prometheus, Titan
Neptune moon
Triton
Mars moon
Phobos
Asteroid
Apollo, Pallas
Dwarf planets
Makemake, Ceres
Orcus = TNO, Trans-Neptunian object not currently a dwarf planet
Was found by first predicting its position
Neptune
Object whose atmosphere has the strongest greenhouse effect
Venus
Object with largest temp. diff (1080 F) from the bright side to the dark side
Mercury
This planet has 67 confirmed moons, making it planet with the most moons - another planet has 62 unconfirmed
Jupiter
“Dwarf” planet with the most known moons
pluto
Terrestrial planet with the highest atmospheric pressure at the surface
Venus
On average the most distant (from the sun) of the objects listed
Eris
Planet with most reflective set of ring particles
Saturn
Has a storm in ats atmosphere that is 3x the size of earth
Jupiter
Entire system of rings and moons is laid over on its side from the plane of the solar system
Uranus
Dwarf planet found near the date of easter. Therefore its name comes from Easter Island mythology
Makemake
Once thought to be a desert world with a large irrigation system of canals on the surface to bring water from the poles
Mars
‘Dwarf; planet that is more likely rocky than icy
Ceres
Object which might break the rule of being in full hydrostatic equilibrium (spherical)
Hamea
Object with currently active plate tectonics
earth
Comet Shoemaker-Levy 9 provided a probe of this objects atmosphere
Jupiter
Discovered by william Herschel in 1781
Uranus
First seen in Feb 1930 on a pair of blinked photographic plates
pluto
Object with the highest average density
earth
Object with the highest average density
earth
In terms of radius, which are the smallest and largest plates in the solar system (just planet, not ring)
Mercury is smallest and Jupiter is largest
Which planets are currently geologically active?
Venus and earth
If we look at the solar system what do we notice about the orbits of the planets?
All the planets orbit about the sun in the same direction
Around which planets do we find rings?
Jupiter, Saturn, Uranus, Neptune
Currently scientists favor the collision-ejection theory to be the origin of the moon. What evidence do they have?
The moon is made of less dense material than the earth and the apollo astronauts found anorthosite on the moon
Lo is currently thought to have a lot of active volcanoes on its surface, which means it is geologically active. Why is lo still geologically active
The tidal forces of Jupiter keep it from solidifying
Which type of object is most likely to become a SHORT period comet?
Scattered Kuiper belt Object (Centaurs)
What do we call an object we see as a flash of light in the night sky?
Meteor
What is the most abundant component of the earth’s atmosphere?
Nitrogen
What is true of earth’s magnetic field?
It protects the earth from the particles of the solar wind
What is true of the dust tail of a comet?
The white one - NOT THE BLUE
What part of a comet always points DIRECTLY away from the sun?
The ion tail
When talking about the objects of the solar system we often refer to them being differentiated. What does this mean?
The heavier elements tend to sink to the middle while the planet is entirely molten
Saturn’s rings are primarily made of what?
Ice balls and ice covered rocks about the size of a snow ball
What do we think causes the magnetic fields of Jupiter and Saturn?
A layer of liquid metallic hydrogen
The Titus-Bode law predicts that there should be a planet orbiting at 2.8 AU from the Sun. What objects are at this location?
A group of rocky bodies that if put together would form an object the size of a small moon
If we were looking for evidence of running water on Mars, which type of rocks would we look for?
Sandstone
There are a number of places in the solar system where we find rocks with long crystal structures. What process do we think causes these long crystals to form?
very lONG cooling time
Meteor showers happen throughout the year. What is the source of most meteor showers?
It comes from the debris left behind with the passing of a comet. The earth then passes through this material
For which of the following would you perform a Widmanstatten test?
an iron meteorite
The first group that is called dwarf planets was discovered in what year?
1801
A dwarf planet is a celestial object that…
has cleared the neighborhood around its orbit
If we found a solar system with a cooler central star what would be true?
Gas giant planets could be closer to the central star
Which planet has the most uniform temp. over its entire surface and why?
Venus bc of the greenhouse effect caused by its atmosphere
What is the definition of Astronomical Unit
The distance from the sun to the earth
Which moon in the solar system has the largest rocky surface?
Ganymede
If someone on one of these distant planets was trying to find planets in our solar system using the transiting method, what would be correct?
Finding Jupiter would be very difficult since it takes 12 years to orbit the sun
If we had a way to travel to other solar systems and we found a small rocky planet that was tidal locked to its star and had no atmosphere, what would be true of the surface temp?
It would have a very wide temp range from dark side to bright side
What is true about the relative sizes of planets, dwarf planets, and moons in the solar system?
Two moons in the solar system are larger than the planet mercury
Which large moon has a thick atmosphere of hydrocarbons, that some feel is much like the early earth?
Titan
The light form the sun hits the surface of a particular moon of another planet. For every 100 photons which hit the surface on average 34 are reflected. What is the albedo of the moon?
0.34
What is related to the magnetic field of the earth?
Aurora borealis - looks like bright lights
T/F scientists feel there will be no more dwarf planets found?
FALSE
T/F scientists feel there will be no more dwarf planets found?
FALSE
T/F Saturn’s rings are most visible bc they have the highest albedo?
TRUE
T/F in order for the solar nebular to begin forming our current solar system material had to be very hot
FALSE
T/F All asteroids are contained in the asteroid belt
FALSE
T/F The jovian planets are made primarily of hydrogen
TRUE
T/F Stony-iron meteorites are the most commonly found
FALSE
T/F there are currently 7 official dwarf planets and 8 classical planets
FALSE
T/F The moons of uranus are named for Shakespearian characters
TRUE
T/F Since the Jovian planets are further out in the solar system they are made entirely of gases, liquids, and ices
FALSE
T/F scientists believe that the planets formed in their current locations
FALSE
T/F Iron meteorites come from the deep interior of differentiated asteroids
TRUE
T/F Iron meteorites come from the deep interior of differentiated asteroids
TRUE
Stars on the main sequence generate energy by what process?
Fusion of hydrogen into helium
When we examine the spectra of a main sequence M star we find bands from Titanium oxide and magnesium Hydride. We also see lines of neutral calcium and iron. What element/molecule is M star primarily composed
Hydrogen
When the first pulsar was discovered in 1967, what was the first theory to explain the regular pulses?
Signals from LGMs (Little gREEN MEN)
Why do sunspots appear dark on the surface of the sun?
The sunspot is cooler than the surrounding material
Why do sunspots appear dark on the surface of the sun?
The sunspot is cooler than the surrounding material
If stars are in a state of hydrostatic equilibrium then which of the following is true?
a combination of gas pressure, radiation pressure, and electron degeneracy pushing outward. With gravity pulling inward
I find a binary system with the following objects. Object A is a red supergiant of 20 solar masses and object B is a neutron star. What is true?
Object B came from a star that was more massive than object A
What critical piece of info can we get from observing binary stars
The sum of the masses of the two stars and the individual masses of each star
What objects does electron degeneracy balance gravity and stop the collapse?
Red dwarf stars, White dwarfs, and brown dwarfs
What is our own estimate of how long a star like the sun will burn hydrogen to helium? (What is the main sequence light-time for a G2 star)
10-11 billion years
We measure a parallax angle for a given star of 0.01 arctics, What is the distance of this star from our solar system
100 parsecs (1 / .01)
Why do we think all type IA supernova can be used as standard candles?
They are all similar white dwarf objects, just below the Chandrasakar limit - when enough material is added to reach the limit they explode
Why do brown dwarf objects never become stars?
Electron degeneracy stops the contraction before the core is hot enough for hydrogen fusion
I have a wide range of colors for stars on the main sequence. For which color would you expect the star to be the least massive?
Red
We see many kinds of nebula in the milky way. What type of nebula is star formation most likely to occur?
Dark nebula
I know as object is 30 parsecs away. How long would it take light to reach us from this object
97.8 years (3.26 * 30 parsecs) (1 parsec is 3.26 lightyears away)
I know as object is 30 parsecs away. How long would it take light to reach us from this object
97.8 years (3.26 * 30 parsecs) (1 parsec is 3.26 lightyears away)
On HR diagram, where do majority of stars reside?
Along the main sequence
I see the following stars Capella (yellow star), Betelguse (red star), Rigel (blue star), Alpha Centauri B (orange star), Sirius (white). What star has hottest surface temp?
Rigel - blue star
If a stellar remnant is too massive to be a white dwarf and too small to be aback hole, what is the force that prevents further collapse?
neutron degeneracy
Why are emission nebulae normally red in color
The hot stars in the field excite the hydrogen gas and the gas then glows from H-alpha emission
What do we cal transportation of energy by the rising of hot gas?
Convection
As we watch the sun over many years we can count the number of sunspots. The number rises and falls in a fairly steady pattern. How long does it take to go from a max number of sunspots to the next maximum
11 years
A standard candle has which of the following characteristics
A known absolute magnitude
Say we have a could with a mass less than .07 solar masses. This form into a brown dwarf with a surface temp. of 2300 K. over time war is true?
It will get cooler over time
A white dwarf gives off light bc why?
Just bc it is hot and gives off black body radiation
Why would it be very difficult to observe a young neutron star?
They have a very small radius and therefore the luminosity is small
Why would it be very difficult to observe a young neutron star?
They have a very small radius and therefore the luminosity is small
If I look up at the sun in the sky and see the disk of the sun, what layer am i seeing?
Photosphere
Proto-stars and pre-main sequence stars both give off light. What is the source of this luminosity
The change in gravitational binding energy as the object shrinks
Two stars with the exact same spectral type and luminosity class (A2 V) will NOT necessarily share what?
Chemical composition
-THEY WILL SHARE: intrinsic brightness, roughly same radius, same temp.
If we could observe the orbits of both halves of a binary system and if star C has a smaller orbit than star D, what is true of the two stars?
Star C is more massive than Star D (more massive = smaller orbit)
What is true of the life time of stars of the main sequence
The least massive stars will have the longest lifetime
As we look in the night time sky we see stars of different colors. What is the reason for the different colors?
The temperature of each star
We have a main sequence star 8 times more massive than our sun. What is generating the majority of the stars energy
Hydrogen fusion by the CNO cycle
When the sun finally reaches the end of its life what do we think will become its core?
It will become a white dwarf
When the sun expands to a red giant for the first time, how far out will the atmosphere extend?
Venus orbit
What evidence do we have that the upper layer of our sun is convective?
Granules in the photosphere
If i find a star closer made primarily of old red stars what is most likely true?
It is a globular cluster in the halo of the galaxy
When the sun dies it will become a red giant. Why does this happen?
An energy increase form a hydrogen burning shell caused the atmosphere to expand. The atmosphere therefore cools off
When the sun dies it will become a red giant. Why does this happen?
An energy increase form a hydrogen burning shell caused the atmosphere to expand. The atmosphere therefore cools off
I need to DIRECTLY measure the distance of a nearby star. What method would i use?
Stellar parallax
We sometimes see large groups of stars called star clusters. What do we NOT assume about stars in the cluster
They all have the same mass
THEY ARE THE SAME WITH:
- started to form at the same time
- stars all have same composition
- stars are roughly same distance from earth
When a star like the sun reaches the AGB stage it can’t burn any further fuel and will lose about 60% of its mass as a planetary nebula. How is the planetary nebula created from the upper material of the star?
A series of thermal pulses that lifts the upper regions of the star off the core
What is true of the highest mass stars that we can know of?
They can burn everything up to iron
What is true of the highest mass stars that we can know of?
They can burn everything up to iron
We observe an unexpected brightening in the nighttime sky. We have data from before the brightening that indicates a single star was at the location before the brightening occurred. Now the star is no longer there. What kind of event happened?
Type II supernova
If the core remaining after this event has a mass of 2.3 solar masses what kind of object will it become?
-a neutron star
If we had instead found a star and a white dwarf in the data before the brightening and that both the star and white dwarf are around after the brightening, what is possible event?
-a nova
What two elements is the white dwarf above made of?
-carbon and oxygen
What is the source of the pulses we see from a pulsar
Jets caused by the magnetic field of the neutron star
Some stars can only burn up to helium. Why can’t these stars of beyond this point and burn carbon and oxygen?
Electron degeneracy doesn’t allow the core to shrink enough so the core can become hot enough to burn these heavier elements
We go out and observe a cluster of stars with characteristics
1) some stars if spectral type A and F (order: OBAFGKM)
2) 500,000 stars total
3) cluster is in halo of galaxy
4) stars are very low in metal content
5) star A is an A5 V and the bluest star on the main sequence
6) Star B is a K8 V
Only knowing star A is the bluest star on the main sequence, what can we determine?
—-the age of the cluster
What would ALWAYS be correct
—star B is less massive
Both Star A and star B are making what conversion in their cores?
—hydrogen to helium
If star B is stable on the main sequence it is said to be in a state of…. HYDROSTATIC EQUILIBRIUM
What is the heaviest element that the most massive stars in this star cluster could form in their core?
—iron
A star in this cluster is using the Proton Proton (PP) cycle to burn hydrogen to helium. What is possible spectral type and luminosity class for this star? ---G2 V
We go out and observe a cluster of stars with characteristics
1) some stars if spectral type A and F (order: OBAFGKM)
2) 500,000 stars total
3) cluster is in halo of galaxy
4) stars are very low in metal content
5) star A is an A5 V and the bluest star on the main sequence
6) Star B is a K8 V
Only knowing star A is the bluest star on the main sequence, what can we determine?
—-the age of the cluster
What would ALWAYS be correct
—star B is less massive
Both Star A and star B are making what conversion in their cores?
—hydrogen to helium
If star B is stable on the main sequence it is said to be in a state of…. HYDROSTATIC EQUILIBRIUM
What is the heaviest element that the most massive stars in this star cluster could form in their core?
—iron
A star in this cluster is using the Proton Proton (PP) cycle to burn hydrogen to helium. What is possible spectral type and luminosity class for this star? ---G2 V
How do we build the elements heavier than iron and nickel in the period table?
R and S process during a supernova explosion
What is population II stars look like
lots and lots of stars in a big group
T/F a star is formed and stars burning hydrogen on the main sequence as on AO star. As the star burns its fuel supply it will move to cooler spectral types and burn out its fuel as an F5 star
FALSE
T/F One person can watch a high mass star go through its entire life cycle
FALSE
T/F some astronomers believe a quark star is possible once we get beyond a neutron star
TRUE
T/F All energy is transported through the sun’s interior by convection
FALSE
T/F sunspots are related to magnetic field lines in the sun
TRUE
T/F If we see a flat bottom on a eclipsing binary light curve it means that it is a partial eclipse
FALSE
T/F the lower the mass of a white dwarf the smaller its radius
FALSE
T/F a pulsating star pulsates bc of an opacity flip from opaque to transparent and back
TRUE
