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45 terms

Astronomy Test 1 Ch 1-4

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On a scale where the sun is about the size of a grapefruit and earth is about 15 meters away, how far away are the nearest stars besides the sun?
about the distance across the united states
how are galaxies important for our existence?
galaxies recycle material from one generation of stars to the next, and without this recycling we could not exist
Which of the following best describes the galaxy?
a spiral galaxy with a disk about 100,000 light years in diameter and containing between 100 billion and 1 trillion stars
Light takes approximately one second to travel from the earth to the moon. this means that the moon is approximately
300,000 kilometeres from the earth
Suppose we look at a photograph of many galaxies. Assuming that all galaxies formed at the same time after the big bang, which galaxy appears to us as the youngest?
the galaxy that is furthest from us
Suppose we imagine the sun to be about the size of a grapefruit. Which of the following describes the size and distance of the earth on the same scale?
earth is the size of a point about 15 meters away from the sun
which is longer, a solar year or a lunar year?
a solar year, because a lunar year is 12 lunar months that are 29-30 days long each, for a total of 354-355 days
a scientific model
uses math and logic to describe and predict the behavior of a real-world system
on the scale of the cosmic calendar in which history of the universe is compressed to 1 year, how long has the human civilization existed?
a few seconds
In the greek geocentric model, the retrograde motion of a planet occurs when
the earth is about to pass the planet in its orbit around the sun
How long does it take our solar system to complete one orbit around the milky way galaxy
230 million years
according to Keplers third law
jupiter orbits the sun at a faster speed than saturn
what do we mean when we say that the universe is expanding
average distance between galaxies is increasing with time
What is the sun mainly made of
hydrogen and helium
an astronomical unit (AU) is
the average distance between earth and the sun
based on observations of the universal expansion, the age of the universe is about
14 billion years
the term observable universe refers to
the portion of the universe that can be seen by the naked eye
how many arc seconds are in one degree
3,600
which of the following statements about circumpolar stars is true at all latitudes
they always remain above your horizon
what makes the north star, polaris, special?
it appears very near the north celestial pole
which of the following statements is true?
Both the northern and southern hemispheres recieve the same amount of sunlight on the equinoxes

the northern hemisphere recieves the most direct sunlight on the summer solstice
which of the following statements about constellations is false
most constellations will be unrecognizeable hundreds of years from now
Which of the following is not a phase of the moon
half moon
if the moon is setting at 6 am the phase of the moon must be
full
if the moon rises around 3 am its phase must be
wanning crescent
in addition to the conditions required for any solar eclipse, what must also be true in order for you to observe a total eclipse
the moons umbra must touch the area where you are located
when are eclipse seasons
when the nodes of the moons orbit are nearly aligned with the sun
ancient people who knew the aros cycle could
predict when an eclipse would happen, but not necessarily what type and where it would be visible
what happens during the apparent retrograde motion of a planet
the planet appears to move eastward with respect to the stars over a period of many nights
why were ancient peoples unable to detect stellar parallax
they did not have the ability to measure very small angles
at approxiamtely what time would a first quarter moon rise
noon
why did ptolemy have the planets orbiting earth on circles upon circles in his model of the universe
to explain the fact that planets sometimes appear to move westward rather than eastward relative to the stars in our sky
he discoverd that orbits of planets are ellipses
kepler
he discovered that jupiter has moons
galileo
the point along a planets orbit where it is closest to the sun is called the orbits
aphelion
what is acceleration of gravity of earh
9.8 m/s^2 downward
if your mass is 60 kg on earth what would your mass be on the moon
60 kg
what quantites does angular momentum depend upon
mass, velocity, and radius
the amount of gravitational potential energy released as an object falls depends on
the distance it falls
considering einstaeins famous equation, e= mc^2 which of the following statements is true
a small amount of mass can be turned into a large amount of energy
which of the following statements correctly describes the law of conservation of energy ?
the total quantity of energy in the universe changes
the mass of jupiter can be calculated by
measuring the orbital period and distance of one of jupiters moons
gasoline is useful in cars because it has
chemical potential energy
which of the following correctly lists our cosmic address from small to large
earth, solar system, milky way galaxy, local group, local supercluster, universe
consider the statement "theres no gravity in space" the statement is
completely false