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