Sci 261 Quiz Answers

Front 1

The process of breaking light down into its component colors creates a/an

Back 1

spectrum.

Front 2

The prefix "kilo" added to a unit of measure (e.g., kilometers) means to

Back 2

multiply that unit of measure by 1000.

Front 3

An educated guess in science is known as a scientific

Back 3

hypothesis.

Front 4

The major source of information about bodies in the universe (outside of Earth) is through

Back 4

their light.

Front 5

A constellation shaped like the letter "W" in the northern sky is named

Back 5

Cassiopeia.

Front 6

The distance between any point on a wave and the next similar point is the

Back 6

wavelength.

Front 7

The positively charged particle contained within the core of an atom is the

Back 7

proton.

Front 8

Wein's Law is useful in astronomy to determine the

Back 8

temperature of a star.

Front 9

Spectroscopy is used in astronomy to

Back 9

determine composition, temperature, and the speed of a star towards or away from us.

Front 10

The visible spectral series (Balmer series) of the hydrogen atom spectrum is produced when electrons in hydrogen atoms transition from higher energy levels and end up on energy level labeled n =

Back 10

two.

Front 11

The Doppler effect can be used in astronomy to measure the

Back 11

speed of a star.

Front 12

A method for improving the images produced by ground-based optical telescopes despite blurring by the Earth*s atmosphere is called

Back 12

adaptive optics.

Front 13

The ability to distinguish between details or to distinguish two adjacent objects as separate is

Back 13

resolution.

Front 14

A radio telescope 100 meters across, when used to measure 10-centimeter waves, is

Back 14

1,000 wavelengths across.

Front 15

A curved lens or mirror can form an image by bringing light to a/an

Back 15

focus.

Front 16

The primary factor determining the resolution of an orbiting reflecting telescope is the

Back 16

diameter of the mirror compared with the wavelength of light being studied.

Front 17

Wet pavement seems darker than dry pavement at night because

Back 17

light from our headlights reflects through specular reflection into the eyes of oncoming drivers.

Front 18

A reflecting telescope of a given mirror diameter has several advantages over a refracting telescope with a lens of the same diameter. Some of these advantages include:

Back 18

Reflecting telescopes have no chromatic aberration and the mirror does not have to be perfectly clear glass like a lens does.

Front 19

An electronic device used to collect light and produce images in modern telescopes (instead of photographic film) is called a

Back 19

CCD.

Front 20

The most obvious difference between the images of planets and stars, as seen from the ground, is that stars

Back 20

twinkle.

Front 21

The annual path of the Sun through the sky, with respect to the stars, is the

Back 21

ecliptic.

Front 22

Many more people observe a lunar eclipse when it happens than would ever observe any solar eclipse because

Back 22

every person on the night side of Earth can observe a lunar eclipse, while a solar eclipse provides total darkness only along a narrow path on the surface of the earth.

Front 23

Suppose you are in California at 3 pm (local time) and you wish to look at the full Moon. The best idea would be to

Back 23

give up and try again later.

Front 24

Lunar eclipses do not occur with every full moon, nor do solar eclipses occur at every new moon, because

Back 24

the Moon and the Earth orbit the Sun in slightly different planes.

Front 25

A magnitude -1 star is about how much brighter than a magnitude +6 star?

Back 25

630 times.

Front 26

Christmas falls during the summer in Australia because

Back 26

the month of December is during summer in the southern hemisphere.

Front 27

Which of the following people important to the development of astronomy is given credit for the idea that the Earth is not the center of the solar system?

Back 27

Copernicus.

Front 28

A satellite orbiting just above the surface of the Earth orbits in about 1.5 hours, then at about how many Earth radii from the Earth's center must a satellite orbit to have a period of 24 hours?

Back 28

6.4.

Front 29

The Sun is positioned at one focus of the orbits of each of the planets in our solar system. What object is positioned at the other focus of these elliptical orbits?

Back 29

Nothing.

Front 30

If the size of an orbit of a planet around the Sun (i.e., its semimajor axis) is increased by a factor of four times, how will the period it takes the planet to orbit the Sun change?

Back 30

It will increase by eight times.

Front 31

Which of the following observational discoveries was made and reported by Galileo?

Back 31

Jupiter's four largest moons, the phases of Venus, craters and mountains on the Moon's surface, and a large number of stars in the Milky Way.

Front 32

Kepler's Second Law (also known as the Law of Equal Areas) implies that

Back 32

planets orbiting our Sun move faster when they are closer to the Sun.

Front 33

The heat energy in the Earth's interior is due to

Back 33

natural radioactivity.

Front 34

Of the inner planets, which has the strongest magnetic field?

Back 34

Earth.

Front 35

The hypothesis that the Moon formed from a ring of material ejected from the Earth by a collision is the

Back 35

ejection of gaseous ring model.

Front 36

Compared with Earth's atmosphere, Venus' atmosphere has a very high concentration of

Back 36

carbon dioxide.

Front 37

High-resolution images from Mars Global Surveyor show layered features and gullies that appear to be

Back 37

due to water flow.

Front 38

Why does Mars appear reddish-orange from Earth?

Back 38

Its rocks have suffered 'rusting' and contain reddish-orange iron oxides.

Front 39

Which of the following statements about the Earth-Moon system is true?

Back 39

The orbital period of the Moon around the Earth and the rotation period of the Moon around its axis are equal.

Front 40

Astronomers have observed that the Moon is more heavily cratered than the Earth. This is primarily because

Back 40

the Moon experiences almost no erosion compared to the Earth, causing craters to remain much longer.

Front 41

Many scientists now believe that liquid water flowed on Mars at some time in the past because of

Back 41

spacecraft rovers' observations of parallel laminations in rocks, spacecraft rovers' observations of spherical beads of hematite, spacecraft rovers' spectrometric evidence of jarosite, orbiting spacecraft observations of fans and deltas in the sand, and spacecraft measurements of water ice in the polar regions.

Front 42

Which of these phenomena are believed to be associated with Earth's magnetosphere?

Back 42

The Van Allen radiation belts and aurorae.

Front 43

Violently volcanic, with perhaps the youngest surface in the solar system is the satellite

Back 43

Io.

Front 44

Compared with the other giant planets, Uranus is evidently unique in having no

Back 44

internal heat source.

Front 45

Neptune's characteristic color is caused by absorption by atmospheric

Back 45

methane.

Front 46

The low average densities of Jupiter and Saturn compared with the density of Earth suggest that

Back 46

they contain large quantities of light elements, such as hydrogen and helium.

Front 47

The planet that rotates 'on its side' as it revolves around the Sun is

Back 47

Uranus.

Front 48

The Roche limit of a planet is the

Back 48

distance from the planet outside which gas and dust could coalesce without being torn apart by tidal forces from the planet.

Front 49

Although supposedly discovered in 1846 after computing the location of an unknown planet that was perturbing the orbit of Uranus, it is likely that Neptune was actually observed by

Back 49

Galileo Galilei.

Front 50

Because of conditions on Titan, the role water plays on Earth may be played by liquid

Back 50

ethane.

Front 51

The name of the space probe that arrived at Saturn in 2004, and has been making scientific observations of Saturn and its moons since then is named

Back 51

Cassini.

Front 52

Which of the following is NOT a possible description of Pluto?

Back 52

A brown dwarf.

Front 53

The largest component of a comet is its

Back 53

tail.

Front 54

Most of the extrasolar planets detected since 1995 are unlikely to harbor life as we know it because

Back 54

they are gas giants, without solid surfaces.

Front 55

Modern theories of solar system formation posit that planets formed through aggregation of many smaller bodies, each perhaps only hundreds of kilometers in size, called

Back 55

planetisimals.

Front 56

Using ground-based telescopes, most massive exoplanets orbiting other stars have been found by

Back 56

looking for a periodic Doppler shift in the star's spectrum as a massive planet causes the star to "wobble" slightly.

Front 57

Jupiter's chemical composition is most similar to that of

Back 57

the Sun.

Front 58

The giant (jovian) planets are large compared with the terrestrial planets because the giant planets

Back 58

obtained and retained more gas and ice because of their large distance from the Sun.

Front 59

Most known comets do not reappear in our sky very often because

Back 59

the orbits of comets are highly eccentric and their semimajor axes are large.

Front 60

The major piece of evidence that Pluto has an atmosphere has been obtained from

Back 60

measuring the gradual decrease, then increase in the light of a known star as Pluto passed in front of (occulted) that star.

Front 61

The light we receive from the Sun comes from the layer of the Sun's atmosphere called the

Back 61

photosphere.

Front 62

The solar corona is so hot it emits mainly

Back 62

x-rays.

Front 63

As the solar atmosphere expands outward into interplanetary space it becomes the

Back 63

solar wind.

Front 64

Areas of the Sun appearing relatively dark when seen in white light are

Back 64

sunspots.

Front 65

The orientation of the Sun's magnetic field changes, repeating a full cycle about every

Back 65

22 years.

Front 66

Which of the following is NOT influenced by the Sun's magnetic field?

Back 66

The Sun's blackbody spectrum.

Front 67

Solar filaments that project into space at the Sun's visible edge are called

Back 67

a prominence.

Front 68

Of the regions of the Sun listed below, which has the highest temperature?

Back 68

The core.

Front 69

Einstein's General Theory of Relativity published in 1916 was verified through which solar event in 1919?

Back 69

Total solar eclipse.

Front 70

Categories of stars based on their respective spectra are called

Back 70

spectral types.

Front 71

The angle at which a star appears to move when observed from the ends of a baseline of 1 A.U. is the star's

Back 71

parallax.

Front 72

A star that is 40 parsecs from the Sun, if moved to a distance of 10 parsecs, would be

Back 72

16 times brighter.

Front 73

A temperature-luminosity diagram of stars usually includes a diagonal band called the

Back 73

main sequence.

Front 74

Star Albert appears to have the same brightness through red and blue filters. Star Bohr appears brighter in the red than in the blue. Star Curie appears brighter in the blue than in the red. Which of the following orderings of these stars has them ordered from coolest to hottest?

Back 74

Bohr, Albert, Curie

Front 75

One can determine the radius of a nearby star (that is not necessarily on the main sequence) knowing only its

Back 75

apparent brightness, parallax, and surface temperature.

Front 76

The Doppler shift of a star depends only on the star's

Back 76

radial velocity.

Front 77

Cepheid variables are useful to astronomers for measuring distance to other galaxies because

Back 77

the period of their variation in brightness is correlated to their average intrinsic luminosity.

Front 78

A way of determining that a globular cluster is old is by charting the population of stars on a temperature-luminosity diagram and noticing that

Back 78

the massive, hot stars are missing from the chart.

Front 79

A stellar sized hot body that derives its energy from free-falling gravitational collapse is a

Back 79

protostar.

Front 80

The fusion process which produces energy in most stars forms helium from the nuclei of

Back 80

hydrogen.

Front 81

The number of neutrons in a neutral atom of 614C is (atomic number=6; atomic mass=14)

Back 81

8.

Front 82

The process of building heavier atoms from lighter ones is called

Back 82

nucleosynthesis.

Front 83

As a protostar is formed from a cloud of gas and becomes a pre-main-sequence star, which one of the following events does NOT occur?

Back 83

The protons in the gas begins to fuse.

Front 84

The amount of energy released in a nuclear fusion reaction is directly proportional to the

Back 84

mass difference between the initial reactants and final products.

Front 85

Brown dwarfs emit electromagnetic radiation primarily as which of the following types of light?

Back 85

Infrared radiation.

Front 86

The so-called neutrino problem of the 1980s and 90s was concerned with

Back 86

detection of only about one-third as many neutrinos from the Sun as were expected.

Front 87

After a star enters its red giant phase its core will heat up enough for the triple-alpha process to begin to produce

Back 87

carbon.

Front 88

When a star becomes unstable, it may eject shells of gas into space forming a/an

Back 88

planetary nebula.

Front 89

Stars retaining less than 1.4 solar masses after their unstable phase will become

Back 89

white dwarfs.

Front 90

Oscillating stars were ruled out as an explanation for pulsars because they would not have the correct

Back 90

period.

Front 91

If, after a Type II supernova, the stellar core is less than 2 solar masses, the result will probably be a

Back 91

neutron star.

Front 92

The Chandrasekhar limit is the

Back 92

theoretical maximum mass which a white dwarf can have without exploding as a nova.

Front 93

High-energy charged particles believed to be produced most of the time by supernovae are called

Back 93

cosmic rays.

Front 94

Which of the following statements about pulsars is true?

Back 94

Pulsars cannot be rotating white dwarfs because their rotation rate is so high that a white dwarf would be ripped apart.

Front 95

When a main-sequence star runs out of hydrogen fuel in its core,

Back 95

the core contracts and thus heats up.

Front 96

If, after a supernova, the stellar core retains more than 2 or 3 solar masses, the result will be a

Back 96

black hole.

Front 97

The spherical surface around a collapsed star in which light can orbit is the

Back 97

photon sphere.

Front 98

The presence of a black hole in a galaxy core can be inferred from

Back 98

the velocities of stars near the core.

Front 99

What three quantities completely define the physical characteristics of a black hole? These characteristics can be used to discriminate one black hole from another black hole.

Back 99

Mass, spin rate, and electric charge.

Front 100

Gamma-ray bursts have been found to be have sources

Back 100

in galaxies billions of light years away.

Front 101

If a massive star (more than ten times the mass of the Sun) should form a black hole, a companion star that had been orbiting this now black-hole-star at a distance of one light-year would

Back 101

continue to orbit in its original orbit.

Front 102

Astronomers believe that when our Sun becomes a black hole far into the future

Back 102

Wait! Our Sun is too small to ever form a black hole.

Front 103

Which one of the following observations is one of the pieces of evidence used by astronomers to detect an object that could potentially be a black hole?

Back 103

Flickering x-rays from an accretion disk around the black hole.

Front 104

A cloud of dust and gas that scatters the light of nearby stars is a/an

Back 104

reflection nebula.

Front 105

The symbol H II would denote a hydrogen atom with a charge of

Back 105

+1.

Front 106

The large (60,000 light-year radius) sphere of older stars and globular clusters around the central region of the Galaxy is the

Back 106

halo.

Front 107

The "spiral arms" of the Galaxy are embedded in the

Back 107

disk.

Front 108

To trace out the spiral structure of our Galaxy we should look at

Back 108

very young objects.

Front 109

The spectral line that has a wavelength of 21 cm is believed to be produced by

Back 109

hydrogen.

Front 110

The astronomer who is credited with first arguing in 1917 that Earth is not at the center of our galaxy is

Back 110

Harlow Shapley.

Front 111

Which one of the following statements about our Milky Way Galaxy is FALSE?

Back 111

Globular star clusters reside in the halo, and contain main-sequence stars spanning all spectral types, from O through M.

Front 112

What were originally called spiral nebulae are now more accurately called

Back 112

spiral galaxies

Front 113

Galaxies are classified according to their

Back 113

shape.

Front 114

In 1929, Hubble announced that a galaxy's distance from us is directly proportional to its

Back 114

redshift.

Front 115

Which of the following are primary distance indicators?

Back 115

Cepheid variables.

Front 116

The discovery that some clusters of galaxies do not have enough visible mass to maintain the structure of the cluster has become known as

Back 116

the missing mass problem.

Front 117

Why is it not surprising that very little star formation is found in elliptical galaxies?

Back 117

Elliptical galaxies tend to consist mostly of old stars and have very little free gas and dust.

Front 118

Astronomers cannot determine the distance to other galaxies using the geometric method of parallax as we do for some stars because

Back 118

galaxies are so far away that any parallax angle would be far too small to measure.

Front 119

The Milky Way Galaxy is a type of galaxy called

Back 119

spiral.

Front 120

Many astronomers believe that most of the dark matter of the universe does not consist of "normal" matter made of protons, neutrons, and electrons, but probably consists of

Back 120

WIMPs.

Front 121

The principle relating the distance of a galaxy and its measured recessional speed is known as

Back 121

Hubble's Law.

Front 122

Astronomers discovered quasars while trying to correlate optical objects in the sky with

Back 122

radio sources.

Front 123

The word "quasar" came from the acronym that was used to identify a

Back 123

quasi-stellar radio source.

Front 124

By current consensus, quasars have at their centers large

Back 124

black holes.

Front 125

The multiple images seen in a gravitationally lensed quasar have all but which of the following?

Back 125

The same light path through space.

Front 126

Galaxies that radiate strongly at radio and x-ray wavelengths are called

Back 126

active galaxies.

Front 127

How does a QSO differ from a QSR?

Back 127

QSO's do not produce much radio frequency radiation, while QSR's produce much radio radiation.

Front 128

The spectra of quasars differs from that of normal stars in that it

Back 128

is greatly red-shifted.

Front 129

Quasars are probably powered by

Back 129

material falling into a central supermassive black hole.

Front 130

Which of the following statements about quasars is true?

Back 130

Quasars probably faded with time, and have now evolved into relatively normal galaxies.

Front 131

The "fuzz" seen around some quasars is evidence for which of the following surrounding the quasar?

Back 131

Galaxy.

Front 132

"Why is the sky dark at night" is an age-old question generally remembered as

Back 132

Olber's paradox.

Front 133

The assumption that the Universe is homogeneous and isotropic is called

Back 133

the cosmological principle.

Front 134

The notion that the Universe had an instant when it began is implied by its

Back 134

expansion.

Front 135

If the expansion of the Universe will eventually stop and reverse, then the Universe is said to be

Back 135

closed.

Front 136

A Universe in which composition and density are the same everywhere at a given time is

Back 136

homogeneous.

Front 137

What kind of universe has a density greater than the critical density?

Back 137

Closed.

Front 138

The cosmological principle states that the universe is assumed to be

Back 138

isotropic and homogeneous.

Front 139

The standard candles that were used to measure distances to other galaxies which led to the discovery of what is now called "dark energy" were

Back 139

Type Ia supernovae.

Front 140

A time far in the future of the Universe, when the density of photons and elementary particles will be very low is known as

Back 140

the dark era.

Front 141

Many astronomers now believe that the expansion of the universe is accelerating, driven by the repulsive effect of the cosmological constant, perhaps caused by something known as

Back 141

dark energy.

Front 142

The force holding the nuclei of atoms together is the

Back 142

strong force.

Front 143

A universe that has not expanded uniformly, but for some very short period in its history expanded rapidly, is called

Back 143

inflationary.

Front 144

Quasars and the cosmic background radiation are the strongest evidence against the

Back 144

steady-state theory.

Front 145

The relative abundances of protons and neutrons was set when the age of the Universe was about

Back 145

1s.

Front 146

One success of the inflationary theory of the Universe is that it can explain why the Universe appears to be

Back 146

flat.

Front 147

The lightest elements (H, He, and Li) formed shortly after the big bang in a fusion process known as

Back 147

primordial nucleosynthesis.

Front 148

There are good reasons to believe that at one time the Universe expanded extremely rapidly. This "inflation" occurred primarily

Back 148

within the first 10-30 seconds after the Universe started expanding.

Front 149

Which of the following prevented photons from traveling long distances in the early Universe?

Back 149

Free electrons easily interacted with the photons, scattering them in many directions.

Front 150

Most scientists now believe that protons and neutrons are not fundamental particles, but consist of small particles called

Back 150

quarks.

Front 151

The hypothesis that other universes (potentially with different physical laws and constants) exist is known as the

Back 151

multiverse hypothesis.

Front 152

In the 1950s scientists at the University of Chicago synthesized complex organic molecules by passing sparks through a mixture of

Back 152

water vapor, methane, and ammonia.

Front 153

The planetary satellite that is thought to have below its surface the liquid water necessary for life as we know it is

Back 153

Europa.

Front 154

The organic molecules that have been found in some meteorites are

Back 154

amino acids.

Front 155

A well-known effort to find intelligent life elsewhere in the Universe is or was called

Back 155

SETI.

Front 156

What is meant by the term "organic compound"?

Back 156

A chemical compound containing carbon.

Front 157

The name given to one equation estimating the probability of life in the Galaxy is the

Back 157

Drake equation.

Front 158

Why do most astronomers dismiss the notion that UFOs indicate that Earth has been visited by extraterrestrial beings?

Back 158

Because of the great distances involved in any intelligent beings travelling to Earth when nothing can travel faster than the speed of light.

Front 159

Around which of the following objects is there thought to be the best chance of finding life outside the solar system?

Back 159

A main-sequence F-type star.

Front 160

Searches for signals from intelligent extraterrestrial life have been conducted mainly at

Back 160

radio wavelengths.

Front 161

According to William Dembski, most people identify designed objects through their

Back 161

complexity and specificity.

Front 162

The ability to distinguish between details or to distinguish two adjacent objects as separate is

Back 162

resolution.