Please enter something

Astronomy Test Review #3

question

The planets in our solar system are thought to have come from
answer

the same cloud of gas and dust in which the Sun formed
question

As the solar nebula collapsed, it became a disk because
answer

the overall rotation of the nebula plus collisions between particles made the particles go in more or less the same direction
question

The outer planets are mostly large and gaseous because
answer

beyond the frost line, the gravity of large, ice-rich planetesimals captured the abundant light gases
question

Because of the temperatures in the protoplanetary disk,
answer

Rocks and metals froze in both the inner and outer regions, and ices froze only in the outer region.
question

As the solar nebula collapsed under its own gravity
answer

It heated and spun up
question

You are sent to find dense and rocky planets. Where in the Solar System should you look?
answer

close to the sun
question

A key characteristic of the cloud from which the Solar System formed was its
answer

rotation
question

Planetary systems form
answer

within the dense disks of material surroudnign ver young stars
question

The current arrangement of continents and oceans on the earth�s surface
answer

is the result of motion of plates
question

The earth’s atmosphere has
answer

changed due to volcanoes, rainwater induced chemical reations, and photosynthesis
question

A planet that is differentiated
answer

must have been sufficiently molten that the denser materials sank to the center
question

The magnetic field of the earth
answer

fluctuates in strength and reverses direction about every 20,000 years.
question

The most useful means to explore the crust and mantle of the earth is
answer

studying earthquakes and seismic waves
question

The convection of hot rocks in the mantle of the earth occurs because
answer

over some ranges of depth, the density is almost constant,
question

We know the interior of the earth is liquid because
answer

earthquake waves that cant go through liquids are blocked by the interior of the earth.
question

If there were no plate motions and continent building,
answer

everything would be under water
question

Continents stay at the surface of the earth because
answer

They are made of low density rock that floats on the mantle
question

Continental motions were first measured directly by
answer

military network of cameras set up to improve how accurately nuclear missiles could hit their targets
question

Craters are caused by
answer

objects crashing into a planet’s surface
question

What is the main reason Mercury is hotter than the Moon?
answer

Mercury is closer to the sun
question

The approximate age of the Solar System is
answer

4.5 billion years
question

A rock sample is analyzed and found to have only 25% as much of a radioactive element as it would have been predicted to contain originally. The half-life of the radioactive element is 8×108 years. How old is this rock?
answer

1.6X10^2
question

The lack of an atmosphere on the moon implies that
answer

it escaped because of the moon’s weak gravity
question

An object with no atmosphere or erosion processes is found in the Solar System with fewer craters on its surface than the lunar highlands. This object
answer

has had a new layer deposited on its surgace since it formed
question

Mercury’s surface looks a lot like
answer

the surface of the moon…
question

Observations of the Moon show that the lunar maria have only 3% as many craters as the lunar highlands. It can be reasoned that
answer

lunar lava flowed across the surface AFTER most of the Moon’s larger craters were created…
question

The composition of the moon is
answer

similar to the earth’s crust…
question

An important scientific result from the Apollo program to send astronauts to the moon is
answer

Bringing back samples that allowed us to determine the ages of the rocks in different areas on the moon…
question

Studying the craters on the moon shows that
answer

the rate of bodies striking the earth fell rapidly after the first 500 million years…
question

Greenhouse gases ____________.
answer

absorb infrared light and transmit visible light …
question

What would the temperature of a planet be if it reflected nearly all the sunlight?
answer

it would be very, very cold…
question

Mars’ surface temperature would be higher if _______
answer

its atmosphere contained more greenhouse gases…
question

The only body other than Earth to show signs of running water on its surface is
answer

Mars…
question

Volcanoes on Mars
answer

are much larger than on earth…
question

The concerns about global warming on the earth arise because
answer

humans are producing large enough amounts of carbon dioxide to increase the greenhouse effect significantly…
question

Our understanding of the temperature on the earth a long time ago is based on
answer

measuring the relative amounts of oxygen isotopes in ancient seashells…
question

The canals on Mars are
answer

an illusion caused by observers trying too hard to see features on the planet…
question

Ultimately, the reason the Martian volcanoes grew to their current sizes is
answer

because mars is too small to retain significant interior heat…
question

“Terraforming” refers to
answer

modifying the atmosphere of a planet to make its climate more like that of the earth…
question

The surface of Venus
answer

is dominated by volcanic geology…
question

Over decade-to-century time spans,
answer

independent measurements of the temperature on earth agree that it is going up…
question

The metallic hydrogen in Jupiter’s interior contributes to
answer

its strong magnetic field…
question

The thermal emission from several giant planets
answer

is larger than would be predicted from the amount of sunlight absorbed by the planets…
question

The high level of motions and activity in Jupiter’s atmosphere results from
answer

convection driven in part by the interior heat of the planet…
question

The low level of oxygen in Jupiter’s atmosphere suggests that:
answer

Jupiter formed around a core that contains a large fraction of its oxygen…
question

The poles and equator on Jupiter do not rotate at the same rate, implying that
answer

Jupiters visible surface is made of liquid or gas…
question

Some planets were able to retain their hydrogen and helium as they formed because
answer

They were cooler…
question

Aurorae are seen around the Earth and Jupiter because
answer

both have strong magnetic fields…
question

Landing a spacecraft on Jupiter would be challenging because
answer

the “surface” is liquid hydrogen…
question

Saturn is most similar to
answer

Jupiter…
question

Uranus is very similar to
answer

Neptune…
question

Moons that come too close to a planet
answer

Will disintegrate…
question

Rings around planets
answer

are common around giant planets…
question

Prior to the Cassini mission, we had not made a good map of the surface features on Titan because
answer

it has a relatively opaque atmosphere…
question

The densest of Jupiter’s large moons are found
answer

close to jupiter…
question

This moon of Jupiter has a relatively smooth icy surface suggesting an underlying ocean.
answer

europa…
question

Volcanoes may occur on a moon because of
answer

Tidal heating…
question

The rings of Saturn are made of
answer

small particles largely of ice…
question

Now that Huygens has landed on Titan, we see that its surface
answer

has drainage channels that look a bit like arroyos…
question

Gaps and sharp edges in Saturn’s rings are caused by
answer

gravitational effects of the planets moons…
question

Pluto’s atmosphere
answer

freezes on plutos surgace when it is far from the sun…
question

A key ingredient in discovering Pluto was
answer

comparison of photographs taken at different times…
question

We have determined the surface compositions of asteroids by
answer

finding pieces of them on the ground and studying spectra of sunlight reflected from them…
question

Comets originate
answer

from cloud surrounding the Solar System…
question

Pluto is likely one of the largest members of
answer

the Kuiper belt…
question

A meteor shower results when
answer

The earth passes through the remnants of a comet…
question

Comets are comprised mainly of
answer

ice…
question

If all the asteroids in the asteroid belt were assembled into a planet, it would be
answer

Less than 1/1,000 of earths mass…
question

No full-sized planet formed between Mars and Jupiter because
answer

Jupiters gravity kept stirring things up so no large object was safe from big collisions
question

The relative lack of craters on the surface of the earth is because
answer

they erode away…
question

What kind of experiment has proven most useful for finding planets around other stars?
answer

measuring accurate Doppler shifts in the stellar spectra to detect the effects of the planets graviational tugs on the stars’ motions…
question

How many planets have we discovered outside the solar system?
answer

about 700…
question

Planetary debris disks are
answer

dust and particles generated by collisions amon small planetary bodies…at least one…
question

The number of planets we know are suitable for life are
answer

at least one…
question

The average temperature at the earth has been constant for the 4 billion years over which life has developed because
answer

the carbon dioxide level in teh atmosphere has changed to produce a greenhouse effect that compensated for changeds in the sun…
question

The ice ages in the last few hundred thousand years seem to have been triggered by
answer

small perturbations in the orbit and polar inclination caused changes in the climate…
question

To determine when ice ages have occurred in the past, we
answer

analyze the isotopes of oxygen in shellfish fossils …
question

Looking back over hundreds of millions of years, the earth
answer

is cooler than average…
question

Planets in the “habitable zone” will
answer

may form life if they retain atmospheres, have the right amount of water, are on circular orbits, and meet other conditions…
question

Habitable zones are the regions
answer

around a star where water on the surface of a planet is likey to be liquid…
question

Life is unlikely to form on planets orbiting stars much more massive than the sun because
answer

they burn their nuclear fuels and evolve off the main sequence too quickly…
question

Long periods when the climate was warmer than average were probably caused by
answer

greenhouse warming due to carbon dioxide released by many volcanoes…
question

The weather is difficult to predict because
answer

weather is a chaotic system, that is, it is very complex and small changes can have larfe consequences …
question

Life could not form in the first few hundred million years of the formation of the earth
answer

because the rapid bombardment of the earth by large bodies made it very hostile to life…
question

The most critical aspects of life are
answer

to harness energy and to reproduce…
question

The very first forms of life we have found
answer

have survived apparently unchanged as the ultimate “living fossils”…
question

Stanley Miller’s experiment is famous because
answer

although eh had the wrong chemicals, he introduced the idea of trying to make chemical precursors to life in the laboratory…
question

Errors, or mutations, in the reproduction of early life
answer

were the underlying force for the development of improved life forms…
question

DNA replication carries the information for new organisms because
answer

DNA attracts bonds specific nucleotides that only pair with other specific nucleotides in the DNA chain, producing a negative copy of itself…
question

Mars is a high priority target for space exploration because
answer

it appears to have many of the conditions needed for life in its early history, so we might find signs that life formed…
question

Mars is an attractive place to look for early life forms because
answer

it is on the edge of the suns habitable zone-life might have formed when it still had oceans of water …
question

Multiple forms of complex animal life first appeared
answer

more than 3 billion years after the first life on earth…
question

Sex was an important development toward advanced life because:
answer

it greatly increased the genetic variety in living organisms…
question

Nucleated, complex cells appear to have formed
answer

by cells developing ways to live together to their mutual advantage …
question

Many Cambrian creatures are related to
answer

arthropods, the group that includes spiders, insects, crabs, lobsters…
question

The rapid development of a broad variety of animals in the Cambrian period occurred
answer

for reasons we are not entirely sure of, although we have a number of ideas…
question

A new development with the Cambrian creatures overall was
answer

hard shells for protection and predators that fed on other animals…
question

Judging by how long it took to happen, the most difficult step toward complex life was
answer

development of nucleated cells…
question

A disaster in which a large asteroid or comet strikes the earth is
answer

bound to happen sooner or later because the giant planets keep deflecting such objects into chaotic orbits…
question

“Chaos” means ___________ to a scientist
answer

the behavior of a system where very small changes can have very large consequences…
question

The means by which the K/T impactor probably killed most of the dinosaurs is
answer

material hurled up into space came back down, heating up to hgih temperature when it struck the atmosphere and baking them…
question

. After the K/T disaster,
answer

primitive mamals like opossums became abundant relatively quickly…
question

Mass extinctions
answer

occur roughly every hundred million years, probably from a variety of causes…
question

Evidence that an asteroid or comet killed the dinosaurs in the K/T extinction includes:
answer

the exsistence of a giant crater off the Yucatan Peninsula, and observations of the recent impacts of a comet on jupitar and a thin layer of iridium-rich material in rock around earth…
question

High iridium content indicates an object came from space because:
answer

iridium is a heavy material and therfore most of that in the earth has sunk to the center…
question

Evidence that large asteroids hit the earth from time to time includes
answer

the record of craters on other solar system bodies…
question

Convergent evolution means
answer

facing similar challenges, different types of animal ten to evolve toward similar solutions…
question

Brain sizes
answer

have tended to get larger with time…
question

Sophisticated, thinking brains and complex nervous and sensory systems developed
answer

to allow location of easily-digested foods…
question

Development of civilization on Earth has waited until sophisticated, thinking brains evolved and
answer

the climate entered a mild period that made it easier to grow food…
question

The number of civilizations we might be able to receive radio signals from
answer

is very hard to estimate- we can only try and see what happens …
question

The probability of a “fair” coin coming up heads is 1/2. What is the probability of it coming up heads three times in a row?
answer

1/8…
question

Animals with relatively large brains
answer

might just be extra-good at sensing and hunting their prey …
question

Infant humans
answer

use most of their body energy to support large and growing brains…
question

The biggest uncertainty in how many civilizations there are right now in other planetary systems around us is probably
answer

how long a civilization lasts before it dies out or destroys itself…
question

Science
answer

has some major events that it cannot explain, like what happend before the Big Bang…