Test 1 Flashcards
What are the Sciences that make up Earth Science?
Geology, Oceanography, Meteorology, Astronomy, Environmental Science
What is Geology?
The study of the solid Earth. Physical geology examines the materials that
comprise the Earth and historical geology aims to understand the origins and
development of the planet.
What is Oceanography?
Examines the composition and dynamics of the world’s oceans. It
also involves the study of coastal processes and seafloor topography as well as
marine life.
What is Meteorology?
The study of Earth’s atmosphere. It includes weather and climate.
What is Astronomy?
Examines Earth as a body in space, both as part of the solar system and
as part of a larger universe
What is Environmental Science?
Includes the study of natural resources, environmental
hazards, and how people influence their environments and Earth processes.
List at least four natural hazards. Aside from natural hazards, describe another important
connection between people and Earth Science.
Different natural hazards include: Earthquakes, Volcanoes, Floods, Tsunami, Hurricanes,
and Landslides. Humans influence Earth by altering its surface. People build cities and
roads, and engineer projects that alter river flooding patterns. People pollute the air, the
land, and the water, changing Earth from what is its natural state.
List two examples of size/space scales in Earth Science that are at opposite ends of the
spectrum.
1) A lightning flash happens within a fraction of a second but can instantly alter the
immediate landscape.
2) Uplift of mountain ranges takes tens to hundreds of millions of years to occur.
How old is the Earth?
Earth is 4.6 billion years old.
If you compress geologic time into a single year, how much time has elapsed since Columbus
arrived in the New World?
3 Seconds.
How is a scientific hypothesis different from a scientific theory?
A hypothesis is an untested explanation for an observed phenomenon. It requires further
observation or testing to see if it is valid. A theory is generally accepted by the scientific
community as the best explanation for observable facts, as it has been subjected to rigorous
scrutiny and tested repeatedly.
Summarize the basic steps used in many scientific investigations.
1)An observation is made about the natural world. 2)Data surrounding that observation are collected. 3)A working hypothesis is developed. 4)More observations and/or experiments are performed to test the hypothesis. 5)The hypothesis is accepted, rejected, or modified. 6)Data and results are shared with the scientific community for critical analysis and
further testing.
Name and briefly outline the theory that describes the formation of our solar system.
The theory that describes the formation of our solar system is the nebular theory, which
states that the early solar system originated as a cloud of dust and gas about 5 billion
years ago as a star gravitationally collapsed. This rotating nebular cloud eventually
contracted into a flattened, rotating disk. The cloud cooled and heavier metallic and rocky
material condensed and accreted into the inner planets. The outer planets formed from
residual gases and ices in the outer nebular cloud.
List the inner planets and outer planets. Describe basic differences in size and composition
Inner planets: Mercury, Venus, Earth, and Mars. These planets are relatively small and
rocky; they are made up largely of metals and silicate minerals.
Outer planets: Jupiter, Saturn, Uranus, and Neptune. These planets are much larger than
the inner planets and are composed of ices and gases.
List the four spheres that constitute the Earth system.
Atmosphere, Hydrosphere, Biosphere, and Geosphere
Compare the height of the atmosphere to the thickness of the geosphere.
The atmosphere is a very thin layer compared to the planet itself. The radius of the solid
Earth is about 6400 km (4000 mi) whereas the entire atmosphere is roughly 160 km (100
mi) thick.
How much of Earth’s surface do oceans cover? What percentage of Earth’s water supply
do oceans represent?
Oceans cover nearly 71% of the planet. They account for 97% of Earth’s water supply.
What is a system. List three examples.
A system is a group of interacting, independent parts that make up a complex whole.
Examples of systems include a city transportation system, a weather system, or an
automotive cooling system.
What are the two sources of energy for the Earth system?
The Sun and Earth’s interior are the two sources of energy for the Earth system.
Compare and contrast continents and ocean basins.
Continents are made of granitic rocks whereas oceans are made of basaltic rocks.
Continents are less dense and thicker than ocean basins
Name the three major regions of the ocean floor. What are some physical features
associated with each?
Continental margins – contains the continental shelf, the continental slope, and the
continental rise. They are the boundary between continents and oceans.
Deep-ocean basins – include the vast, flat abyssal plains of the ocean bottom. They
also contain deep ocean trenches and seamounts in varied stages of erosion.
Oceanic ridges – are divergent plate boundaries where new igneous rock is
formed. These are vast winding ridges of underwater volcanic mountains that wind
around the Earth.
Describe the general distribution of Earth’s youngest mountains.
Earth’s youngest mountains are generally found at the margins of continents along as
opposed to the stable interior of continents.
What is the difference between shields and stable platforms?
A shield is a large stable area of very old crystalline rock. A stable platform is a shield
covered by sedimentary rock
Why did the ancients believe that celestial objects had some influence over their lives?
Early cultures noticed a connection between the seasons, tides, floods, and certain
celestial bodies. Because seasons, tides, and floods were important in their agriculture, they
believed that the heavenly bodies also controlled this part of their lives.
What is the modern explanation of the “guest stars” that suddenly appeared in the night sky?
They are normal stars that are usually too faint to be visible but increase in
brightness as they explosively eject gases from their surface. They are known as novae or supernovae
Explain the geocentric view of the universe.
The geocentric view of the universe places Earth at the center of all planetary bodies,
including the Sun and stars. The idea is that all other things revolve around a motionless Earth
Describe what produces the retrograde motion of Mars. What geometric arrangements did
Ptolemy use to explain this motion?
The retrograde motion of Mars is due to Earth having a faster orbital speed than
Mars. From the point of view of a stationary Earth, Mars appears to move backward, or
retrograde. Ptolemy described this motion geometrically by proposing that the planets orbited on
small circles (epicycles) revolving on large circles (deferents
What major change did Copernicus make in the Ptolemaic system? Why was this change
philosophically different?
Copernicus proposed a heliocentric model with the Sun at the center of the solar
system. It was philosophically different because it was considered heretical to not view
Earth as the center of the universe.
What data did Tycho Brahe collect that was useful to Johannes Kepler in his quest to
describe planetary motion?
Tycho Brahe collected precise observations about the locations of Mars.
Who discovered that planetary orbits are ellipses rather than circles?
Johannes Kepler discovered that planetary orbits are ellipses rather than circles
Explain how Galileo’s discovery of the phases of Venus supported the Copernican view of
a Sun-centered universe
Galileo discovered that the planet Venus exhibits phases that would be impossible in
Ptolemy’s geocentric model. In addition, the phases of Venus also changed size,
indicating that Venus was closer to Earth when a “crescent,” and farther away when
close to “full.” This could be most simply explained by saying that Earth and Venus
were both orbiting the Sun, with Venus’ orbit entirely inside the Earth’s orbit.
How are the constellations used in modern astronomy?
Modern astronomers use constellations to roughly identify the area of the night
sky they are observing.
How many constellations are currently recognized
Eighty-eight constellations are currently recognized.
Describe the celestial sphere
The celestial sphere is a conceptual sphere with Earth located at its center and
all objects in the sky projected upon the inner surface of the celestial sphere. The
poles of the celestial sphere are aligned with the poles of the Earth. The celestial
equator lies along the celestial sphere in the same plane that includes the Earth’s
equator.
Describe how you can use your outstretched hand to estimate angular distances.
With your hand held out at arm’s length, the angular distance represented by
your hand with fingers fully spread is about 20 degrees. The width of your index
finger is about 1 degree, and the width of your closed fist represents about 10
degrees.
Describe the three primary motions of Earth.
Rotation—Earth rotates on its axis once every 24 hours.
Revolution—Earth orbits the Sun once per year.
Precession—Earth’s axial tilt slowly changes direction every 26,000 years
Explain the difference between the mean solar day and the sideral day.
The mean solar day is the interval between noon on one day and noon the next day. The
sidereal day is how long it takes Earth to make one rotation, which is 23 hours, 56 minutes, 4
seconds.
Define ecliptic.
The ecliptic is the apparent path of the Sun during the course of one year.
Compare the synodic month with the sideral month
The synodic month is 29.5 days, or how long it takes for the Moon to pass through all its
phases. The sidereal month is how long it takes the Moon to orbit Earth, which is 27.3 days.
The moon rotates on its axis very slowly. How does this affect the lunar surface
temperatures?
Because the Moon rotates on its axis very slowly, there is a high temperature on the day
side of the Moon and a very low temperature on the night side
What phenomenon results from the fact that the moon rotates once on its axis for every
orbit that it makes around the Earth?
Because the Moon’s periods of rotation and revolution are the same, the same side of the
Moon always faces Earth
How many eclipses normally occur each year?
There are a total of four eclipses per year: two solar and two lunar.
Solar eclipses are slightly more common that lunar eclipses. Why, then, is it more likely
that your region of the country will experience a lunar eclipse than a solar eclipse?
A lunar eclipse is visible to anyone on the side of Earth facing the Moon but a solar
eclipse is only visible for a geographically narrow zone that is never wider than 275
kilometers, the diameter of the Moon’s shadow
How long and a total eclipse of the moon last? How about a total eclipse of the Sun?
A total eclipse of the Moon can last 4 hours and a total eclipse of the Sun can last 7
minutes.
Briefly outline the steps in the formation of our solar system, according to the nebular theory.
The Sun and planets began to form in a rotating cloud of nebular gas and dust. These materials
eventually clumped together with a hot protosun at the center and chunks of planetesimals rotating
around it. Through repeated collisions, the planetesimals grew into protoplanets, and eventually the
solar system came about.
By what criteria are planets considered Jovian or terrestrial?
Planets are considered either terrestrial or Jovian based on their location, size, and density
What accounts for the large density difference between Jovian and terrestrial planets?
Different chemical compositions.
Explain why the terrestrial planets have a meager atmosphere compared to the Jovian planets
Terrestrial planets were formed in a region where it was too hot for ice and gas to condense but
the Jovian planets formed in colder locations. The terrestrial planets also are too small to exert the
gravitational pull required to hold very light gases in their atmospheres.
Briefly describe the origin of the Moon.
A bolide the size of Mars collided with a young, molten Earth, causing ejected debris to be thrown
into orbit around the Earth. Eventually this material condensed into the Moon.
Compare and contrast the Moon’s maria and highlands
Maria are smooth, basaltic plains. Highlands are elevated several kilometers above the maria and
are breccias. The maria tend to appear dark and the highlands appear light from Earth.
How are the maria on the Moon similar to the Colombia Plateau in the Pacific Northwest?
They are both made from fluid basaltic lavas that spread across a flat area.
How is crater density used in the relative dating of the Moon’s surface features?
The greater the crater density, the older the feature is estimated to be.
Summarize the major stages in the development of the modern lunar surface.
Formation of the original crust, excavation of the large impact basins, filling of maria basins, and
formation of rayed craters.
What body in our solar system is most like Mercury?
Earth’s Moon is most like Mercury.
Venus was once referred to as Earth’s twin. How are the two planets similar? How do they differ
from one another?
Venus and Earth are of very similar sizes. Both are terrestrial planets, with volcanic activity,
surface topography, and mantle upwelling. However, the atmospheres of these two planets are
very different, as are the surface temperatures, with Venus being much hotter. As a result, Venus
has volcanoes that are shorter and wider
What surface feature do Mars and Earth have in common?
Volcanoes, polar ice caps, lava plains, and sand dunes are all surface features that Mars and Earth
have in common.
Why are the largest volcanoes on Earth so much smaller than the ones on Mars?
Mars lacks plate tectonics; successive volcanic eruptions will accumulate in the same place rather
than the volcanoes being relocated by way of plate motion.
What evidence suggests that Mars had an active hydrologic cycle in the past?
Stream-like features with teardrop shaped islands suggest flowing water, valleys that appear to have
been made by catastrophic flooding, dendritic drainage networks, and minerals that form only in the
presence of water are all found on Mars.
What is the nature of Jupiter’s Great Red Spot?
Jupiter’s Great Red Spot is a giant cyclonic storm.
What is distinctive about Jupiter’s satellite Io?
Jupiter’s satellite Io is one of only three volcanically active bodies other than Earth known to exist
in the solar system.
How are Jupiter and Saturn similar?
Jupiter and Saturn both have dynamic atmospheres made of hydrogen and helium, both have rings,
both have many satellites, and both are the two largest planets.
Ring moons exert _ on rings by _ and they also sweep up _.
gravitational pull, altering their orbits, ring particles and subsequently eject them
Saturn’s satellite _ and Neptune’s satellite _ are both the only satellites in the solar system
known to have _.
Titan and Tritan. Substantial atmospheres.
Compare and contrast asteroids and comets. Where are asteroids found?
Asteroids are made of rocky and/or metallic material and are similar in composition to the
terrestrial planets. Comets are less consolidated and made of ice, dust, and small rocky particles
more typical of the outer portion of the solar system.
Where are most comets thought to reside? What eventually becomes of comets that orbit close to the
sun?
Comets are thought to reside in the Oort cloud and the Kuiper belt. Comets that orbit close to the
Sun eventually vaporize
Differentiate among the following solar system bodies: meteoroid, meteor, meteorite
A meteoroid is a small, solid particle that has entered Earth’s atmosphere from space. A meteor is
the streak of light seen as the meteoroid burns in the atmosphere. A meteorite is the remains of a
meteoroid that makes it all the way to Earth’s surface
What are the three main sources of meteoroids?
The three main sources of meteoroids are: interplanetary debris missed by the gravitational sweep
of the planets during the solar system formation, material that is ejected from the asteroid belt, and
the rocky and/or metallic remains of comets that once passed through Earth’s orbit.
What characteristic does a celestial body possess to be classified as a dwarf planet?
To be classified as a dwarf planet, a celestial body must orbit the Sun and be essentially spherical
due to its own gravity but not large enough to sweep its own orbit of debris.
What term is used to collectively describe gamma rays, X-rays, ultraviolet light, visible
light, infrared radiation, and radio waves?
Electromagnetic radiation.
What color in the visible spectrum has the longest wavelength? The shortest?
In the visible region of the spectrum, red has the longest wavelength and violet has the
shortest.
How does the amount of energy in a photon relate to its wavelength?
Shorter wavelengths have photons of higher energy
What is spectroscopy?
Spectroscopy is the study of the properties of light that are wavelength dependent.
What can be learned about a star (or other radiating objects) from its absorption line
spectrum?
Absorption line spectra can tell about the composition of a star or celestial object.
Describe the relationship between a radiating body and the wavelengths of light it emits.
Hotter objects radiate a larger proportion of their energy at shorter wavelengths.
Briefly explain the Doppler effect and explain how astronomers determine whether a star is
moving toward or away from the Earth.
In the Doppler effect, there is a shift in waves of all media when they are approaching an
object that is different from when they are moving away from an object. For light from a
star, its light appears redder than it actually is if it is moving away and its light appears
bluer than it really is if it is moving closer.
What two properties make telescopes with large mirrors more useful than those with small
mirrors?
Increased light-gathering area and greater potential resolution
List two advantages of Charged-Couple Devices (CCDs) over photographic film
Charge-coupled devices can detect more incoming light than film, and they are easily
calibrated for variations in wavelength sensitivity. They can also collect light over several
nights and synthesize it into one image.
Name the technique devised by astronomers to greatly eliminate the blurring caused by
atmospheric turbulence.
Adaptive optics is the technique devised by astronomers to greatly eliminate the blurring
caused by atmospheric turbulence
Why are radio telescopes much larger than optical telescopes?
Radio telescopes are much larger than optical telescopes because radio signals from space
are weak so large telescope dishes are needed to intercept a signal strong enough for
detection.
What are some of the advantages of radio telescopes over optical telescopes
Much radiation from space objects cannot penetrate the atmosphere and be detected by
optical telescopes but can be detected by radio telescopes; radio waves are much stronger
than visible radiation.
Explain why space makes a good site for an optical observatory.
Space is a good site for an optical observatory because there is no Earth atmosphere to
distort or prevent penetration of optical signals and there is no light pollution
Why is the Sun significant to the study of astronomy?
The Sun is significant to the study of astronomy because it is the only star close enough to
Earth to allow easy study of its surface.
Why is the photosphere considered the Sun’s “surface”?
The photosphere is considered the Sun’s surface because it makes up the bulk of the bright
disk that we see and is separate from the incandescent gases that surround it.
What fuel does the Sun consume?
The Sun consumes hydrogen (protons) as fuel in a nuclear fusion process.
What did Galileo learn about the Sun from his observation of sunspots?
Galileo was able to determine that the Sun rotates on its axis about once a month by his
observations of sunspots.
Briefly describe the 11 year sunspot cycle
The number of sunspots on the sun varies in an 11-year cycle; similar numbers of sunspots
occur every 11 years. This cycle is driven by the Sun’s magnetic field.
Why are sunspots cooler than the surrounding photosphere?
Sunspots are cooler than the surrounding photosphere because the Sun’s magnetic field
disrupts the convective flow below the sunspot, which would normally allow hot gasses to
reach the surface.
How does the Sun compare in size and brightness to other main-sequence stars?
Our Sun is in the midpoint of the range for these stars and considered to be average in
terms of size and brightness.
Define absolute magnitude.
Absolute magnitude, or luminosity, is the true brightness of stars compared to a standard
Describe how the H-R diagram is used to determine which stars are “giants”
These stars are compared with stars of known size that have the same surface temperature.
If one red star is more luminous than another red star, it must be larger. Stars with large
radiating surfaces are classified as giants and exist in the upper-right portion of the H-R
diagram.
Describe how main-sequence stars become giants
The usable hydrogen is consumed and a helium-rich core is left. With no energy source, the
core lacks gas pressure needed to support itself against the gravitational pull. The core
contracts and gravitational energy is converted to thermal energy, some of which is
radiated outward, generating more hydrogen fusion in the region around the core. This
additional heat expands the star’s outer gaseous shell and it becomes a large red giant star.
Why are less massive stars thought to age more slowly than more massive stars, despite the
fact that they have much less “fuel”?
The less massive stars burn energy more slowly and never reach high enough temperature
and pressures to fuse helium.
List the steps thought to be involved in the evolution of Sun-like stars.
The steps involved in the evolution of Sun-like stars includes: nebula, protostar, main-
sequence star.
Explain how it is possible for the smallest white dwarfs to be the most massive
The atoms in these white dwarfs have been squeezed together so tightly that the electrons
are pushed very close to the nucleus.
What is the final state of a medium-mass (Sun-like) star?
The final state of a medium-mass (Sun-like) star is a white dwarf.
How do the “lives” of the most massive stars end? What are the two possible products of
this event?
The most massive stars end in a supernova. The two possible products of this event are a
neutron star or a black hole.
Compare the three main types of galaxies.
Spiral galaxies are flat and disk-shaped with a greater concentration of stars in the center.
They have spiral arms extending from the center. Elliptical galaxies are ellipsoid to nearly
spherical like spiral galaxies, but they lack the spiral arms. Irregular galaxies might once
have been spiral or elliptical galaxies but were distorted by gravity. These galaxies have no
symmetry.
What type of galaxy is our Milky Way?
Our Milky Way galaxy is a spiral galaxy.
Describe a possible scenario for the formation of a large elliptical galaxy?
Two smaller spiral galaxies converged in the same area and merged, forming a large
elliptical galaxy.
Explain how Edwin Hubble used Cepheid variables to change our view of the structure of
the universe.
These bright variable stars cycle through brightness at a known rate. Hubble examined
these in fuzzy patches in the sky and determined that these fuzzy patches, now known as
galaxies, lie outside the Milky Way. Thus astronomers came to realize that the universe
was much larger than had been thought
In your own words explain how astronomers determined that the universe is expanding.
Astronomers determined that the universe is expanding by measuring red shifts due to the
Doppler effect as they observed galaxies.
Which view of the universe is currently favored: the Big Crunch or the Big Chill?
The Big Chill is the currently favored view of the fate of the universe.
