Astr100 final exam

What did newton discover by comparing an apple on earth to the orbiting moon as seen in the mechanical universe video?
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What did newton discover by comparing an apple on earth to the orbiting moon as seen in the mechanical universe video?
Both fall toward the earth at different rates dependent on their distances from the earth's center, but independent of their masses.
Who described the motion of planets with 3 laws
Kepler
The strength of gravity between 2 objects is directly proportional to _____ and inversely proportional to___.
The product of their masses; the square of their separation
I'm the absence of air resistance, any free falling object near the surface of the earth will accelerate downward at 9.8 m/s/s no matter what mass it has
True
Applying the universal law of gravity for the moon we can see why things accelerate downward on its surface by what fraction of what we see for g on earth?
1/6
Horoscopes assign astrological signs based on where the Sun was in the sky when you were born. We saw that the Sun was not located in the astrologically expected constellation for a given birth date. Why was the Sun's position off by almost a full constellation?
Earth's precession causes a drift in the coordinate system, which changes modern positions of the Sun relative to the background stars and astrology was founded almost 2,000 yrs ago.
Which coordinate system described is only good for pinpointing something in the sky at your current location and time?
The horizon system
What 2 pieces of information do we need to know about a small planet in order to calculate the mass of its host star?
The semimajor axis of the planets orbit and the time it takes for the planet to orbit the star
Approximately how far up above the southern horizon would the celestial equator cross the local meridian for an observer just north of minnesota whose latitude is 50 degrees?
40 degrees
If the sun is crossing the celestial equator, what do we call this event? Choose all that apply
Vernal equinox, and autumnal equinox
During the winter solstice, the suns declination will be-23.5 degreesDuring the Vernal Equinox the Sun's Right Ascension will be...0 hoursIf you were located at the earths equator where would the celestial equator be located?It would run directly overhead from West to East.What is special about the constellations that make up the zodiac?They all lie along the eclipticWhat did the Cosmos video we watched in class at the beginning of the semester describe as the outer boundary of the Sun's gravitational influenceOort CloudThere hasn't been enough time in the 13.8 billion year lifetime of the Universe for the light to reach us beyond what?The cosmic horizon of the observable Universe.What is our "cosmic address" from small to large?Earth, solar system, Milky Way Galaxy, Local Group, Virgo Supercluster, observable universeYou hold a 1 kg mass in your hand while standing on earth. How much does this mass weigh?9.8 NThe measurement of how high in the sky an object is observed above the horizon from your location is known as...AltitudeWhat is true of the precession of earths axis?1 cycle is 26,000 yearsWhat is meant by synchronous rotation of the moon?It keeps the same side of the Moon towards the earth at all times and rotates once on its axis per orbit around the Earth.The natural tendency of an object to resist changes in motion is calledinertiaA solar eclipse can only occur when the moon falls of the____ and its phase is____Ecliptic; newThe first every asteroid from another solar system was recently discovers. What is true about its velocity in our solar system?It exceeds the escape velocity of the sun and is therefore in an open hyperbolic pathWhat causes the retrograde motion seen in the sky for mars?The earth overtakes the object as the earth moves faster in its inner orbit.If Earth were twice as far from the Sun as it is now, the gravitational force between Earth and the Sun would be1/4 as muchIf you go out at exactly 9 PM each evening during the course of a month, the position of a given star will appear to of moved westward by tens of degrees. what causes this apparent motion?The revolution of the earth around the sunAn object orbits the sun with a semi major axis of 35 A.U. About how long is its orbital period?207 yearsWhich choice is 380,000,000 in scientific notation?3.8 x 10^8Astronauts in orbit around earth float in their spacecraft becausethey are in free fall towards the earthWhich scientist is credited as the first astronomer to use telescopic observations to support the heliocentric modelGalileo GalileiHow would a planet at one AU orbit differently than a planet at 5 AU?It takes less time to orbitIf the earths axis was not tilted and the ecliptic and the celestial equator fell on the same plane, the seasonal variationsWould be almost nonexistentDeclination is measured fromcelestial equatorWhat must your latitude on earth be if you measure an altitude of Polaris to be 30° above the northern horizon?+30 degreesMost of the planetary orbits in our solar system are circular and therefore have eccentricities that are approximately:0.0What is the phase of the moon if it is rising when the sun is setting?fullSolar and lunar eclipses are rare becausethe Moon's orbital plane is tipped by 5.2° relative to Earth's orbital plane.If the sun is located at one focus of earth elliptical orbit what is that the other focus?NothingThe ____ day is The true rotation of the earth with respect to the stars While the ___ day is the basis of our 24 hour daySidereal; synodicSince the moon orbits the earth in the same counter clockwise motion as the earth orbits the sun, how does the sidereal orbital period of the moon compared to the synodic period of the moon that we see as the time for a full cycle of phases?The sidereal period is a couple days shorterWe saw a video that showed an astronaut on the moon who dropped a ___ and a _____ that both fell with constant _____ and hit the ground at ____ timehammer, feather, acceleration, the sameThe light year is a unit ofdistanceIf you observe a full moon at midnight about how long will it be until there is a new moon?2 weeksA planet in retrograde motionshifts westward with respect to the starsAccording to newtons second law if the same force is applied to a second object with twice the mass of the first how will the second object moveWith half the accelerationIf the sun was magically removed from the universe the earth would continue in a nearly circular orbitFalseWhen you compare Newton second law ( with weight as the force) to the Universal law of gravity for an apple the____ cancels out leaving you with____Mass of the Apple; acceleration due to gravity "g"How are modern telescopes design to have an aperture greater than 40 inches in diameter?Make a primary objective mirror of the size needed Make a primary objective out of many smaller mirrors that add up to an effective primary of the size needed.A telescope has a primary objective with a focal length of about 2000 mm. What will the magnification be if we use a 20 MM focal length eyepiece?100xWhy is the Hubble space telescope resolution better than a similar telescope of the same size that is observing from earth?The Hubble space telescope is truly diffraction limited resolving power while the earth bound scope is dominated by atmospheric seeing.How much more light with a 16 inch telescope collect versus an 8 inch telescope4x as muchWhat variables determine the resolving power of a telescope?Aperture size, wavelength observedThe equation described in class allows for the magnification of a telescope to be found by....Dividing the primary objectives focal length by the eyepiece is focal length.A region around a star where a planet can have liquid water is considered a habitable region and is often referred to as the Goldilocks Zone.TrueThe first extrasolar planets discovered were found by which method?Doppler effectThe first reported extrasolar planet was discovered in ______ and was called __________.1995; 51 Pegasi bWhich method of extra solar planet discovery requires the planet to periodically pass in front of the host star?TransitThe radial velocity method using the Doppler effect of extrasolar planet discovery is the one that provides us with information on the planets massTrueIf we discovered a 4th planet around 51 Pegasi what would it be called?51 Pegasi eThe hot Jupiters that have been discovered with orbits close to their host stars also must have formed in that close proximity.FalseJeff Marcy is setting up to observe a star using the Keck telescope in Hawaii and the telescope operator comments that the seeing at the observatory is .85 arc seconds. Is this a good value for a ground based observatory?It's excellentIf someone tells you they have an 8 inch telescope what does this meanIt's The diameter of the primary objective or apertureOnly a few exoplanets have been detected by direct visual (or infrared) observations, Fomalhaut b is one example.TrueWhat is the difference between brightness and luminosity?Brightness is how bright the star appears to us; luminosity is how much light it emits.Star A has an apparent magnitude of 3 and star B has an apparent magnitude of 5. Which star is brighter in our sky?Star AGiven the inverse Square law for light and object that is three times farther away than another similar object will appearOne ninth as brightIf I stores parallax is .1 arc seconds what is its distance10 parsecsStellar trigonometric parallax is used to directly determine a stars...DistanceTo measure the parallax of nearby stars from earth, we would make two measurements of the stars position separated by6 monthsMagnification is the single most important characteristic of an astronomical telescopeFalseThe speed of light was first measured by what observations?Timing of Jupiter's moons as they move behind Jupiter in their orbitsHow do the wavelength and frequency of yellow light compared to the wavelength and frequency of green light?Yellow light has a longer wavelength and lower frequency than green lightList different types of electromagnetic radiation in order of increasing frequency from lowest to highestRadio waves, infrared, visible, ultraviolet, x-rays, gamma raysAs wavelength increases, the energy of a photon__ and its frequency ____Decreases; decreasesA prism is able to spread white light into a spectrum of colors based on the process ofrefractionAn object is observed in the visible (around 550 nm) by 2 telescopes: telescope a has an objective that is twice the size of telescope b. How does the defraction limited resolving power of telescope a compare to telescope bTwo times smaller which is better than telescope BThe hydrogen gas tube demonstrated in class produce what kind of spectrumEmissionA black body radiates at 10,000 K. The peak of this blackbody curve will occur at what wave length?290 nmEvery element has its own unique pattern of spectra, which allows us to identify substances by analyzing their lightTrueA signal sent to the nearest star will get there faster sent by x-rays rather than radio wavesFalseWhich conservation law of physics is responsible for the surrounding area of a protostar to form a disk from which the planets are formedConservation of angular momentumObservatories that use adaptive optics provide higher spatial resolution images primarily becauseadjustable mirrors are used to correct the blurring due to Earth's atmosphereUltraviolet radiation is hard to observe primarily becauseEarth's atmosphere easily absorbs it.What causes molecular clouds to collapse to form a solar systemSelf-gravityWhat must occur for a protostar to become a starfusion in its coreYou record the spectrum of a star and find that the calcium absorption line, who's rest wavelength is 393. Three NM, has an observed wavelength of 392.6 nm. What is true about the radio velocity of this star?It is moving towards us at approximately 500 km/sWhen an electron moves from a higher energy level of an atom to a lower energy levela specific frequency of photon is emittedThe HR diagram is a plot of stellarLuminosity (y axis) vs temperature or spectral type (x axis)About what mass (in solar masses) is the upper limit for what we would consider a low mass star?8 solar massesIn the video about Solar neutrinos it said that they are produced by the first step in the proton proton chain. How was their travel through the sun described?Near the speed of light and shooting straight out of the sun in about two secondsIn the video about solar neutrinos, what was the initial problem with detecting solar neutrinos?Only a third were detected.I'm the video about solar neutrinos, What was discovered about them that solve the solar neutrino problem?They change flavor as they travel from the sun and were detected in their different forms by several detectors around the world, there by accounting for all of themHow many flavors of neutrinos were discovered?3The nature of neutrino flavors means that they are not completely masses, which may have implications on describing the mass of the universeTrueWhat happens during the 11 year solar cycle?Dark spots go through A complete cycle of few or none, to Many, and back to few, or none againWhere are we in the current solar cycleGoing from min to max in the next few yearsAs the sun ages, but before the ultimate end of its life, the outer layers will _____ white the core____ leading to a ____ surface thereby becoming a_____Expand; contracts; cooler; red giantWhy is Neil Degrasse Tyson wrong about the fate of serious and it's White dwarf companionThe orbital size is too great for the red giant ever spell matter over two as white dwarf companyWhile a nova event can happen many times from matter of a companion star dumping onto a white dwarf it will completely explode if the white dwarfs mass reaches about 1.4 solar masses in a type Ia supernova.TrueWhat particles experience a degeneracy in a solar type star, which provides the pressure needed to hold up a white dwarf against gravity in the absence of nuclear fusion?electronsVery low mass stars are convective to the core, unlike the sun, and can use almost all of the hydrogen for fuelTrueA very low mass star is called a _________ and can live for ________ years.red dwarf; a trillionA star like the sun (1 solar mass) will be able to fuse up to what element before shedding its outer layers and ending its life as a white dwarf?CarbonHow might the earth escape being engulfed by the suns later red giant phase?The Sun's loss of a third to about half its mass will move the Earth to a larger orbit.Degenerate matter in the core of a solar type star is responsible for the helium flash as well as the final state as a white dwarfTrueApproximately what is the Swharzchild radius for a black hole that has a mass of 10 solar masses?30 kmWhat is true about a star on the main sequence with more mass compared to one with less mass?It has more fuel, but will burn through it faster and live shorterA seven solar mass star will fuse up to iron in the car and ultimately explodeFalseType II Supernovae come from a wide range of high mass stars, therefore they make great standard candlesFalsePulsars are associated with what type of star?neutron starsType La supernovae can't be classified as standard candles because they are caused by a wide range of high mass starsFalseIntrinsically variable stars that actually pulsate (change their sizes and surface temperatures) on a regular basis and are on the upper mass range with periods of 1 to 100 days are associated with what type of star?CepheidsCepheids and RR Lyrae stars vary in brightness with periods that are directly linked to what property?luminosityA standard candle means we know it's____ and can use it to compare to its measured apparent___ to solve for its____Luminosity; brightness; distanceHow did we derive the Swharzschild radius (Rs) formula for a black hole?It was simply a special case of the escape velocity formula where Vesc was made to be the speed of light CDue to special relativity what can you say about the time a photon experiences relative to you since it was produced in the Big Bang?It would not experience any time before entering your eye nearly 14 billion years laterWhy do sunspots appear dark?they are cooler than their surroundingsThe Sun will likely stop being a main-sequence star in5 billion yearsAn iron core cannot support a massive main-sequence star because ironcannot fuse with other nuclei to produce energyEssentially all the elements heavier than iron in our galaxy were formed:by supernovaeSunspots, flares, prominences, and coronal mass ejections are all caused bymagnetic activity on the sunGeneral RelativityIs a better description of gravity as matter bending space-time around itA neutron stars mass is contained in a sphere with a diameter approximately the size of:A citywhite dwarf stars mass is contained in a sphere with a diameter approximately the size of...EarthPhotons have no mass, and Einstein's theory of general relativity saystheir paths through spacetime are curved in the presence of a massive body.Black holes are stellar remnants with nearby stellar companions can be found by searching for....Variable x-ray sourcesOn average it can take the energy of a gamma ray photon produced in the core about a year to find its way to the outer layers of the sunFalseIn order for the lighthouse effect in pulsars to work, what must be true?Their magnetic axis is not aligned with their rotational axisWhich of the following contributes the largest percentage of total mass of a spiral galaxy?dark matterIn astronomy, isotropy means that the universe is the same __________, and homogeneity means that the universe is the same __________.in all directions; in all locationsAstronomers determined the radius of an AGN by measuring howQuickly it's light variesWhat best summarizes the existence of supermassive black holes?Supermassive black holes occur in most, if not all, large galaxies.The distances to Galaxies used to establish Hubble's law are found from:Standard candles, such as supernovaThe light that comes to us from active galactic nuclei comes from a volume about the size ofsolar systemThe orbits of stars in elliptical galaxieshave random orientationsAll the light in an AGN outburst is emittedat the same timeEvidence of a supermassive black hole at the center of the Milky Way comes fromdirect observations of stars that orbit it, strong radio emission from the region of the accretion disk, and X-rays from material that is falling in.Hubble's law was discovered using measurements of two properties of a galaxy: _______ and _______.distance; recession velocityAn elliptical galaxy may appear round ifit has one axis shorter than the other two but is viewed parallel to the short axis, all three axes are the same; it is spherical in shape, all three axes are different lengths, but it is viewed from a special angle, and it is elongated along one axis, but it is viewed parallel to the long axis.What most accurately describes the spiral arms?The stars move in and out of the arms while they rotate around the galaxy center.Both red and blue stars form inside the spiral arms. Then both stores begin to move out of the arms, but the blue stars die before they can get very far.TrueDescribe the visible distribution of mass within the galaxyThe highest concentration of mass is in the center of the galaxy, and it decreases with increasing distance from the centerWhat does the abundance of heavy elements tell you about the origin of a star?The more heavy elements a star has the more recently it was formedAstronomers know that dark matter is present in galactic halos because the speeds of orbiting stars___ far from the center of the galaxyRemain about constantHow do astronomers detect dark matter?by comparing luminous mass to gravitational massThe Milky Way has globular clustersTrueThe Milky Way is an elliptical galaxyFalseThe Milky Way has 2 major armsTrueThe Milky Way is mostly dark matterTrueOlder stars are found farther from the midplane of a galactic disk becausethe stars have lived long enough to move thereWhy are most of the Milky Way satellite galaxies so difficult to detect?They are very faintCosmic rays arehigh energy particlesLooking toward the galactic center, we see no red shift or blue shift this tells us:The sun in the center are not moving toward or away from each otherDark matter was first detected because the _________ for the amount of gravity that could be present due to the luminous mass.rotation speed of galaxies was too highWhy is the Andromeda galaxy now moving toward us?This is due to the mutual gravitational attraction between the Milky Way and Andromeda galaxies.