What advantage do you gain by having two eyes that are separated on your face, rather than being very close together?
Better collecting area, which allows you to see dimmer objects
Double vision, which allows you to see multiple objects at once
Color vision, which allows you to determine temperatures
Stereoscopic vision, which allows you to determine distances
Better magnification, which allows you to see smaller objects
To measure the parallax of the most distant stars measurable, we would make two measurements of the star's position on the sky separated by:
Stars A and B appear equally bright, but star A is twice as far away from us as star B. Which of the following is true?
Star A is twice as luminous as star B
Star A is four times as luminous as star B
Star B is four times as luminous as star B
Star B is twice as luminous as star A
Star A and star B have the same luminosity because they have the same brightness
Which sequence correctly lists the spectral classes of stars in order from hottest to coolest?
The faster-moving star in a binary is:
The less massive star
The more massive star
The smaller radius star
The larger radius star
The lower temperature star
On a typical H-R diagram, where are the stars with the largest radii located?
In the upper left corner
in the upper right corner
In the center
In the lower left corner
In the lower right corner
The one property of a main-sequence star that determines all its other properties is its:
Hydrostatic equilibrium is a balance between:
Heat and centrifugal force
Core temperature and surface temperature
Pressure and gravity
Radiation and heat
Centrifugal force and gravity
The majority of the Sun's energy come from:
Nuclear fission of uranium
Burning material as in a fire
If the core of the Sun were hotter than it is now, how would the Sun's energy production change?
It would produce less energy per second then it does now
It would produce more energy per second than it does now
Its energy production would vary more than it does now
Its energy production would be more stable than it is now
The Sun's energy production would not change
What do astronomers mean when they say that the Sun makes energy by hydrogen burning?
The Sun is combusting hydrogen in a fire and releasing energy
The Sun is fusing hydrogen into uranium and releasing energy
The Sun is made of mostly hydrogen at very high temperature
The Sun is fusing hydrogen into helium and releasing energy
The Sun is accumulating hydrogen from the solar wind and releasing energy
Which of these can travel directly from the center of the Sun to Earth in about 8 minutes?
The magnetic field of the Sun is continuously produced and deformed by:
Its differential rotation
The solar wind
Changes in the rate of nuclear fusion in the core
Liquid conducting layer in the interior
This is a trick question, the solar magnetic field is primordial
If you could watch stars forming out of a gas cloud, which stars would form first?
The ones with most natural talents
Stars with more heavy elements
Warm ionized gas in the interstellar medium appear _____ when imaged in the optical region of the electromagnetic spectrum.
21-cm radiation is important because:
It allows us to study the deep interiors of stars
It allows us to image magnetic fields directly
It allows us to study neutral hydrogen in the interstellar medium
It is produced by every object in the universe
It is the longest wavelength of light that can naturally be produced
An accretion disk forms around a collapsing protostar because infalling material must conserve:
The source of energy for a contracting protostar comes from:
Gravitational potential energy
Of the following processes at work in molecular clouds, which is the one that inevitably dominates the clouds's evolution?
Conservation of angular momentum
What critical event transforms a protostar into a normal main-sequence star?
Planets in the accretion disk
The star grows suddenly larger in radius
Triple alpha reactions begin in the core
Nuclear fusion begins in the core
Convection begins throughout the star's interior
A nova is the result of which explosive situation?
Mass transfer onto a white dwarf
Helium burning in a degenerate stellar core
A white dwarf which exceeds the Chandrasekhar limit
The collision of members of a binary system
Runaway nuclear reactions in the core
The principal means by which high-mass stars generate energy on the main sequence is called:
The proton-proton chain
The carbon-carbon reaction
The triple-alpha process
The CNO Cycle
Massive stars synthesize chemical elements going from helium up to iron:
Throughout the interior
Primarily at the surface
Only in the core of the star
Along the equator of the star
In a deep convection zone in the interior of the star
What causes massive stars to expel their outer layers?
High magnetic fields
Emission of neutrinos
During the main-sequence evolution of a massive star, increasingly heavier elements are fused in the core, giving the core support for:
Longer and longer times
Shorter and shorter times
An approximately equal amount of time
Approximately 10,000 years
Only a few days
The Crab Nebula is an important test of our ideas about supernova explosions because:
People saw the supernova and later astronomers found a pulsar inside the nebula
The system contains X-Ray binary
The nebula is expanding slowly, as expected from mass loss rates in massive stars
Crabs must have evolved before humans
Astronomers observed the merger of the two stars
Which of these begins first in the core of a massive star?
Silicon fusion to iron
Neon fusion to magnesium
Carbon fusion to neon
Helium fusion to carbon
Hydrogen fusion to helium
Where did all heavy elements in the Sun come from?
Previous generation of stars seeded the interstellar medium out of the Sun formed
Nearby supernova explosions directly contaminated the Sun's surface
Nucleosynthesis within the Sun generated all the elements we see in the solar spectrum
The Sun gobbled up some planets during the early days of our Solar System
The solar wind carries away hydrogen and helium, leaving behind the heavy elements
Iron has 26 protons in its nucleus, and gold has 79 protons. Where did all the gold on the Earth come from?
Nucleosynthesis on the surfaces of neutron stars
Nucleosynthesis that took place in supernova explosions
Nucleosynthesis in the cores of low-mass stars
Nucleosynthesis in the cores of massive stars
Nucleosynthesis in red giant and horizontal-branch stars
According to Einstein's relativity, which two quantities are different manifestations of the same thing?
Mass and gravity
Light and energy
Energy and mass
Temperature and energy
Distance and time