Exam Flashcards
The speed of light is….
300,000 km/s
The Big Bang created….
The universe
About how long does it take for light to travel from the Sun to Pluto?
5 hours
About how long does it take for light to travel from the Sun to Earth?
8 minutes
Most asteroids orbit the Sun between the orbits of….
Mars and Jupiter
Stars are born in regions of space containing….
Enormous clouds of gas and dust
A waning crescent moon rises….
Between midnight and sunrise
A waxing gibbous moon rises….
Between noon and sunset
The third quarter moon sets at about….
Noon
One of Copernicus’s great advances was to….
Determine the relative distances of each planet from the Sun
Which astronomer determined that gravity is responsible for keeping the Moon in its orbit around the Earth?
Newton
Eclipses can possibly occur about once every….
Six months
What causes the four seasons: Fall, Winter, Spring and Summer?
The 23.5 degree tilt of the Earth’s rotation axis
The Sun appears to travel south, then north, then south again during the year. The extreme north and south points of this apparent journey are called…..
Solstice points
The Moon’s orbit is tipped relative to the Earth’s orbit at an angle of about…..
5 degrees
The dates of solar eclipses get shifted from one year to the next because of….
Precession of the Moon’s orbit
What does it mean to say that the universe is expanding?
The average distances between galaxies is increasing
Epicycles were introduced into the ancient geocentric model of the solar system in an attempt to….
Better describe planetary motions
Overall, the universe appears to be…
Expanding, but at a rate that appears to be increasing
The evidence for the existence of “dark matter” within galaxies is that….
Visible matter within galaxies appears to be influenced by more force than can be accounted for by visible matter closer to the centre of the galaxy
If a star rises tonight at 10:00pm, tomorrow it will rise at about….
9:56pm
An equinox is a position on the Earth’s orbit for which….
The day and night are equally long
As seen from the Earth’s equator, the north celestial pole is….
On the horizon
On the first day of Spring, the Sun sets….
Directly west
As described by Kepler’s third law of planetary motion….
Planets closer to the Sun have shorter periods
Which of the following was a valid argument against the heliocentric model proposed by some ancient Greek astronomers?
Stellar parallax was not observed
The first use of telescopes in astronomy was by….
Galileo
At the time of Galileo and Kepler, which of the following observations was the strongest evidence for the heliocentric model of the solar system?
The gibbous and the quarter phases of Venus
An advantage of the Renaissance heliocentric model of the solar system (over the geocentric model) is that….
Apparent retrograde motions of planets is easier to explain
Kepler’s first law of planetary motion is a statement about
The shape of planetary orbits
What is inertia?
The tendency of a body to remain at rest or moving in a straight line at constant speed
According to Newton’s laws of motion, the acceleration of a body….
Is proportional to the net force acting on it and inversely proportional to its mass
According to Newton’s laws of motion, an object moving in a circle at a constant speed is subject to a force pointing….
Toward the centre of the circle
TRUE OR FALSE: It is possible to determine the mass of a planet from the orbital data (the period and the orbital radius) of one of its satellites.
True
We can tell that the net force acting on the Earth is not zero because….
The Earth’s path around the Sun is not a straight line.
The first scientist to propose that there must exist some force that holds the planets in their orbits….
Kepler
Your weight is….
Greater on Earth than it is on the Moon
The first scientist to propose a theory of gravity that was mathematical and to prove that an inverse-square force of gravity is consistent with celestial observations was….
Newton
The magnitude of the gravitational force that the Earth exerts on the Moon is equal to the magnitude of the gravitational force that the Moon exerts on the Earth. Therefore….
The resulting acceleration of the Earth is much less than the resulting acceleration of the Moon, because the Earth is much more massive than the Moon
Which type of radiation has the longest wavelength?
Radio wave
Red and green light differ because….
They have different wavelengths
Infrared radiation differs from red light in….
Its wavelength
Which type of radiation has the shortest wavelength?
Blue light
Which type of photon has the lowest energy?
Microwave radiation
Which type of photon has the highest energy?
Red
Continuous spectra are produced by….
Solids or high-density gases
When a star’s light passes through its cooler atmosphere….
Photons of certain wavelengths are absorbed
Which is the most important power of a telescope?
Light-gathering
Some stars “twinkle” because of….
Atmospheric blurring
Which of the following types of radiation from outer space cannot be detected in a ground-based observatory?
X-ray
Wien’s law is typically used in astronomy to….
Determine the temperature of a star
When white light passes through a cool gas, we see….
An absorption line spectrum
The largest optical telescopes at present are….
Reflectors
An electron bound to an atom….
Can have only a certain energies, which depend on the atom
You observe two stars, one blue and the other red. What can you conclude?
The blue star is hotter than the red star
Protons and neurtrons in an atomic nucleus are held together by….
Strong nuclear forces
When an electron in an atom makes a transition from a higher energy level to a lower energy level, the atom….
Emits a photon of a specific frequency
If you heat a gas so that collisions are continually elevating electrons to higher energy levels, when the electrons fall back to lower energy levels, the gas produces….
An emission line spectrum
With a telescope that has a Newtonian focal arrangement, the viewing is done from….
The side of the telescope
Using spectroscopic parallax enables one to determine a star’s….
Distance (using the H-R diagram)
Which term describes a pair of stars that we can determine are orbiting each other only by measuring their periodic Doppler shifts?
Spectroscopic binary
Ockham’s razor….
Suggests that for scientific theories with equal predictive power, the simpler theory is better
The nuclear fusion of hydrogen into helium inside a star begins at a temperature of….
At least 10 million degrees
We know that the Sun’s energy does not result from a chemical burning process because….
The Sun would have burned up already
About _____ elapse between times of maximum solar activity.
11 years
Sunspots appear dark because….
They are fairly bright but appear dark against the even brighter background of the surrounding surface
Energy is transported from the Sun’s core to its surface mainly by….
Radiation and convection
When four hydrogen nuclei fuse to form a helium nucleus, the total mass at the end is _____ the total mass at the beginning.
Less than
Sunspots are areas on the Sun….
That are cooler
The Sun is supported against the crushing force of its own gravity by….
Gas pressure
Granulation of the Sun’s surface is a direct consequence of….
Convection
The Sun’s mass is about _____ times the Earth’s mass.
300,000
The diameter of the Sun is about _____ times the Earth’s diameter.
100
The thinnest layer of the Sun is the….
Photosphere
Which of the following parts of the Sun is hottest?
Corona
The layer of the Sun that we normally see is the….
Photosphere
A solar prominence is….
A huge plume of glowing gas that juts from the lower chromosphere into the corona
What causes aurorae on Earth and some other planets?
Solar wind
On a Hertzsprung-Russell diagram, stars that are cool and luminous are found towards the….
Upper right
On a Hertzsprung-Russell diagram, stars that are cool and dim are found towards the….
Lower right
On a Hertzsprung-Russell diagram, stars that have the largest radii are found towards the….
Upper right
On a Hertzsprung-Russell diagram, main-sequence stars that have the largest mass are found towards the….
Upper left
On a Hertzsprung-Russell diagram, white dwarf stars are found towards the….
Lower left
On a Hertzsprung-Russell diagram, red giant stars are found towards the….
Upper right
Main sequence stars that have low mass are….
Dim and cool
TRUE OR FALSE: The farther away a star is, the larger is its parallax angle.
False
Binary star systems are important because they are used to determine….
Masses of stars
Since most stars are born with approximately the same composition, what characteristic most determines how they will differ?
Their initial mass
Most stars are born with approximately the following composition.
About 75% hydrogen, about 25% helium, and less than 2% heavier elements
The most abundant chemical element in a main-sequence star is….
Hydrogen (H)
The star nearest to the Sun is at a distance of about….
4 light-years
