Astronomy Ch. 3 The Solar System
How do the densities of the jovian and terrestrial planets compare?
All terrestrials are more dense than any of the jovians.
the jovian planet that orbits closest to the Sun.
Jupiter
For what other motion would your weight also be greater than your normal weight?
The elevator moves downward while slowing in speed.
Imagine that Venus is in its full phase today. If we could see it, at what time would the full Venus be highest in the sky?
at noon
When would a new Venus be highest in the sky?
at noon
Rank the planets from left to right based on their average orbital distance from the star, from longest to shortest.
biggest to smallest
rank the planets from left to right based on the amount of time it takes each to complete one orbit, from longest to shortest.
biggest to smallest
Most of the surface is covered with liquid water
earth
The Ptolemaic model of the universe
explained and predicted the motions of the planets with deferents and epicycles.
In Ptolemy's Earth-centered model for the solar system, Venus's phase is never full as viewed from Earth because it always lies between Earth and the Sun. In reality, as Galileo first recognized, Venus is __________.
full whenever it is on the opposite side of the Sun from Earth, although we cannot see the full Venus because it is close to the Sun in the sky
Suppose you are in an elevator. As the elevator starts upward, its speed will increase. During this time when the elevator is moving upward with increasing speed, your weight will be __________.
greater than your normal weight at rest
A contribution of Newton to astronomy
his differential calculus lets us calculate planetary motions more accurately. The Moon pulls as strongly on us as we do on it. Artificial satellites could be put into orbit about the Earth. The Sun's gravity is greatest on a planet at perihelion, so the planet must speed up.
Scientists today do not accept the Ptolemaic model because
it was too complicated, compared to Copernicus' heliocentric model.
Suppose you are in an elevator that is moving upward. As the elevator nears the floor at which you will get off, its speed slows down. During this time when the elevator is moving upward with decreasing speed, your weight will be __________.
less than your normal weight at rest
Use Kepler's third law to rank the planets from left to right based on their orbital periods, from longest to shortest
longest- three earth masses, one earth mass 2 au shortest- two earth masses, one earth mass 1 au
The only rocky planet to have more than one moon
mars
The planet that orbits closest to the Sun
mercury
about 30 times as far from the Sun as our own planet.
neptune
When would you expect to see Venus high in the sky at midnight?
never
The planet with the lowest average density
saturn
rank the planets from left to right based on their average orbital speed, from fastest to slowest.
smallest to biggest
A planet whose distance from the Sun is 3 AU would have an orbital period of how many Earth-years?
square root of 27 = 5.2
If you are standing on a scale in an elevator, what exactly does the scale measure?
the force you exert on the scale
true or false ? Kepler found the orbits of planets are ellipses, not circles.
true
has a rotational axis that is tilted so much it lies nearly in the plane of its orbit.
uranus
the planet with the highest average surface temperature.
venus
In Ptolemy's Earth-centered model for the solar system, Venus always stays close to the Sun in the sky and, because it always stays between Earth and the Sun, its phases range only between new and crescent. The following statements are all true and were all observed by Galileo. Which one provides evidence that Venus orbits the Sun and not Earth?
we sometimes see gibbous (nearly but not quite full) Venus
