PSCI Exam 1
A major difference between pseudoscience and science is that pseudoscience
has no tests for wrongness
As a clump of interstellar gas contracts to become a main-sequence star, its changing position on the H-R diagram tells us __________.
how its outward appearance is changing
Is the rate of Earth's rotation increasing or decreasing?
it is decreasing
The longest living stars are those of
low mass
The longest-lived stars are those of
low mass
A white dwarf is a former
low-mass star
The Big Bang
marked the beginning of space and time
In science, facts
may change
One of Edwin Hubble's discoveries is that the known universe is expanding. This means that
most all observable galaxies are moving away from each other.
A synthesis of facts and well-tested hypotheses is:
A theory
In science, a theory is
a synthesis of a large body of well-tested knowledge
Which is hotter−−a red star or a blue star?
blue star
A supercluster is a
cluster of galactic clusters
How many spiral galaxies are in the Local Group?
3
According to calculations made by modern astronomers, the age of the universe is close to
14 billion years
What is the approximate age of the universe?
14 billion years
Scientists estimate the age of our universe to be about
14 billion years old
Astronomers who subscribe to the Big Bang theory believe the Big Bang occurred
15 billion years ago and at the beginning of time
Natural philosophy
*Become science as answers were found *was at one time the study of unanswered questions about nature
In a scientific experiment, a control is
*a test that duplicates an experimental test except for one variable *a way to study the effects of just one experimental variable
An explanation or answer that is capable of being proved wrong is
A hypothesis
how deep is the Photosphere
500 km
What launched the era of modern science in the 17th century?
The era of modern science in the 17th century was launched when Galileo Galilei revived the Copernican view of the heliocentric universe, using experiments to study nature's behavior.
The observable universe is
The minor portion of the universe we can observe
What is meant by the term supernatural? Does science deal with the supernatural?
The term supernatural literally means "above nature." Science does not deal with the supernatural because it works within nature, not above it.
Luminosity is
The total amount of light energy that a star emits into space
Cosmic background radiation refers to
Uniformly distributed residual radiation that resulted from the Big Bang
Science and technology are
related to one another, but not the same thing
As the falling rocket plunges toward the event horizon, an observer in the orbiting rocket would see that the falling rocket __________.
slows down as it approaches the event horizon, and never actually crosses the event horizon
The Big Bang is regarded as the expansion of
space
On the H-R diagram our Sun is a
star of average luminosity and temperature
Because a white dwarf is no longer burning fuel, it is more accurately described as being a
stellar remnant
Relativity is the
study of how space, energy, and mass are related to time
The star nearest the Earth is
sun
Supernovae are one of the most extreme events in the known universe. They are caused by
the collapse of a supermassive supergiant star.
"Cosmological Redshift" refers to
the expansion of space itself
Evidence for the Big Bang is
the long wavelength radiation that permeates the universe and the slowing down of galaxies as they recede
What is the reference that astronomers use to denote the luminosity of stars?
the luminosity of the sun
What determines if a star becomes a white dwarf, a neutron star, or a black hole?
the principal factor is mass
Cosmology is the study of the overall structure and evolution of
the universe
The event that changes a protostar to a full-fledged star is
thermonuclear fusion.
A person who says "That`s only a theory" likely does not know that scientific theory is a
vast synthesis of well-tested hypotheses and facts
When does a newly forming star have the greatest luminosity?
when it is a shrinking protostar with no internal fusion
A scientific hypothesis may turn out to be right or it may turn out to be wrong. If it is a valid hypothesis, there must be a test for proving it
wrong
What will be the predominant element within the Sun after it has died?
carbon
Which of the following is not accepted evidence for the Big Bang?
dark energy
How far is a light year?
nearly 10 trillion km
Something that competent observers can observe and agree to be true is
A scientific fact
Which statement is not scientific hypothesis? 1. Albert Einstein was the greatest physicist of the 20th century 2. Atoms are the smallest particles of matter that exist 3. The Moon is made of Swiss cheese
Albert Einstein was the greatest physicist of the 20th century
The study of living matter is
Biology
Which of these often changes over time with further study?
Both facts and theories
The study of how matter is put together, how atoms combine to form molecules, and how the molecules combine to make the materials around us is:
Chemistry
Why do we believe that focusing on math too early is a mistake in an introductory science course?
Focusing on math too early is a poor substitute for concepts.
How did Galileo disprove Aristotle's idea that heavy objects fall faster than light objects?
Galileo showed the falseness of Aristotle's claim using experimentation.
Most of the constellations in use today originated in ________mythology
Greek and Middle Eastern
How is the definition of the word theory different in science versus in everyday life?
In everyday speech, a theory is the same as a hypothesis −− a statement that has not been tested. In science a theory is a synthesis of a large body of verified information.
Polaris is always directly overhead at
North Pole
What are the outward and inward forces that act on a star?
Outward force is exerted by thermal pressure; inward force is gravitational contraction
The study of such concepts as motion, force, energy, matter, heat, sound, light, and the components of atoms is:
Physics
What type of galaxy is the Milky Way?
Spiral
The synthesis of a large collection of information that contains well-tested and verified hypotheses about certain aspects of the world is known as a scientific
Theory
From the viewpoint of an observer in the orbiting rocket, what happens to time on the other rocket as it falls toward the event horizon of the black hole?
Time runs increasingly slower as the rocket approaches the black hole.
Technology *is an important tool of science *is sometimes the fruit of science, as in medicine that cures diseases *is a human endeavor *can be used to elevate or to diminish the human condition
True
The fields of science *overlap *merge into one another, such as biophysics, biochemistry, geophysics, astrophysics, and bioastrophysics *are acknowledged to present a cohesive study of the natural world
True
If we can't see dark matter, how do we know it is there?
We can detect dark matter by its gravitational effects.
Specifically, what do we mean when we say that a scientific hypothesis must be testable?
We mean that it must be capable of being proved wrong.
In what sense do we say we are looking back in time when we are looking at the stars?
We see stars as they once were when their light reaches us.
Listed following are distinguishing characteristics of different end states of stars. Match these to the appropriate consequence of stellar death.
White Dwarf: •supported by electron degeneracy pressure •typically about the size (diameter) of Earth •has a mass no greater than 1.4 MSun •in a binary system, it can explode as a supernova Neutron Star: •sometimes appears as a pulsar •usually has a very strong magnetic field Black Hole: •size defined by its Schwarzschild radius •viewed from afar, time stops at its event horizon
A hypothesis that has been tested over and over and not contradicted is:
a law
What do astronomers expect will be left at the center of our solar system once the Sun has gone through all its life stages?
a planet-sized diamond
What is an H−−R diagram?
a plot of luminosity versus surface temperature for stars
After our Sun burns its supply of hydrogen, it will become a
a red giant
The Milky Way is
a spiral galaxy
The Milky Way galaxy is
a spiral galaxy, in the process of colliding with the Magellanic Cloud galaxies, where earth resides
What are the relative compositions of the materials from which stars form?
about 74% hydrogen, about 24% helium, no more than 2% other materials
If you were inside the rocket that falls toward the event horizon, from your own viewpoint you would __________.
accelerate as you fall and cross the event horizon completely unhindered
Using science to analyze nature
adds depth to our understanding and therefore adds to our appreciation of nature.
What is the relationship between the heavy elements that we find on Earth today and supernovae?
all elements beyond iron were once produced by supernova
An active galactic nucleus
arises from the gigantic black hole at the center of a galaxy
If you were inside the rocket that falls toward the event horizon, you would notice your own clock to be running __________.
at a constant, normal rate as you approach the event horizon
The "redshift" of a galaxy refers to the rate
at which is receding
How did Mr. Hubble calculate the age of the universe?
by measuring the rate of expansion of the universe
Rank these elements in order of increasing abundance in the universe: (a) helium, (b) hydrogen, (c) carbon.
carbon, helium, hydrogen
Edwin Hubble discovered that the farther away a galaxy is the
faster it is receding from us
When a newly forming star is at its greatest luminosity, what is its energy source?
gravitational contraction
Elliptical galaxies
have little in the way of dust and gas, are thought to be former starburst galaxies, and tend to be smaller than the other types of galaxies.
A star's brightness tells us
how much energy a star produces
Most of the atoms in the universe are thought to be
hydrogen
An explanation of answer that is capable of being proved wrong is:
hypothesis
In science, an educated guess is a
hypothesis
The North Star has very little apparent rotation in the night sky because
it lies directly in the Northern path of the projection of the Earth's axis of spin
What is the determining factor in the stages a star will progress through from birth to death?
its mass
A star's color tells us
its surface temperature
A galaxy contains
large amounts of gas, dust, and stars.
Of the sciences known as physics, chemistry, and biology, the most basic is
physics
The "Big Bang" refers to the
point in time in which the known (and perhaps knowable) universe came into being.
A black hole is
the remains of a giant collapsed star
a black hole is
the result of the collapse of supergiant star, .a region of space that is collapsed in on itself., and likely found at the center of each spiral galaxy.
If experimental findings are not reproducible,
the results are not considered valid
The event horizon of a black hole is
the surface below which no matter or energy can escape
