Assignment 2

Earth is closer to the Sun in January than in July. Therefore, in accord with Kepler's second law:

Earth travels faster in its orbit around the Sun in January than in July.

Which of the following was not a major advantage of Copernicus's Sun-centered model over the Ptolemaic model?

It made significantly better predictions of planetary positions in our sky.

In the Greek geocentric model, the retrograde motion of a planet occurs when:

The planet actually goes backward in its orbit around Earth.

Kepler's third law states that for any planet orbiting the Sun, the orbital period squared (p2 ) is equal to the average orbital distance cubed (a3), or p2=a3 . This implies that __________.

a planet with a large average distance from the Sun has a longer orbital period than a planet with a smaller average distance from the Sun

What type of visible light spectrum does the Sun produce?

an absorption line spectrum

according to kepler's second law, jupiter will be traveling most slowly around the sun when at _______

aphelion

According to Kepler's second law, as a planet or other object moves around its orbit, it sweeps out equal __________ in equal __________.

areas / times

The set of spectral lines that we see in a star's spectrum depends on the star's:

chemical composition

Tycho Brahe's contribution to astronomy included:

collecting data that enabled Kepler to discover the laws of planetary motion

A star whose spectrum peaks in the infrared is:

cooler than our sun

Kepler's first law states that the orbit of each planet is an ellipse with the Sun at one focus. Which of the following statements describe a characteristic of the solar system that is explained by Kepler's first law?

earth is slihtly closer to the sun on one side of its orbit than on the other side the sun is located slightly off-center from the middle of each planet's orbit

the extent to which mars orbit differs from a perfect circle is called its _____

eccentricity

earth orbits in the shape of an _______ around the sun

ellipse

Consider two triangles that represent the swept-out area in some time period as an object orbits the Sun. If one triangle is short and squat (where the object is close to the Sun) and the other is long and thin (where the object is far from the Sun), then the object must have moved __________.

farther in the case where the triangle is short and squat

earth is located at one _______ of the moon's orbit

focus

shortest wavelength to longest wavelength

gamma rays, xrays, ultraviolet, visible light, infrared, radio waves

Blue light has higher frequency than red light. Thus, blue light has:

higher energy and shorter wavelength than red light

When we say that a planet has a highly eccentric orbit, we mean that:

in some parts of its orbit it is much closer to the Sun than in other parts

which forms of light are lower in energy and frequency than the light that our eyes can see

infrared and radio

Why is a sunflower yellow?

it reflects yellow light

The energy of a red photon is ____ the energy of a blue photon.

less than

Galileo's contribution to astronomy included:

making observations and conducting experiments that dispelled scientific objections to the Sun-centered model.

According to Kepler's second law, planets and other objects orbiting the Sun move fastest when they are __________.

nearest the sun

The neon "OPEN" sign appears reddish-orange because __________.

neon atoms emit many more yellow and red photons than blue and violet photons

If Earth were twice as far from the Sun, the force of gravity attracting Earth to the Sun would be:

one-quarter as strong

The time a planet takes to complete one orbit is called its __________.

orbital period

The point along a planet's orbit where it is closest to the Sun is called the orbit's

perihelion

according to keplers second law, pluto will be traveling fastest around the sun when at ________

perihelion

when considering light as made up of individual "pieces," each characterized by a particular amount of energy, the pieces are called

photons

Kepler's second law states that as a planet orbits the Sun, it sweeps out equal areas in equal times. Which of the following statements describe a characteristic of the solar system that is explained by Kepler's second law?

pluto moves faster when it is closer to the sun than whe it is farther from the sun

lowest energy to highest energy

radio waves, infrared, visible light, ultraviolet, xrays, gamma rays

lowest frequency to highest frequency

radio waves, infrared, visible light, ultraviolet, xrays, gamma rays

the mathematical form of keplers third law measures the period in years and the _________ ____ in astronomical units (AU)

semimajor axis

The higher the energy of a photon, the ________ its wavelength.

shorter

Which of the following conditions lead you to see an absorption line spectrum from a cloud of gas in interstellar space?

the cloud is cool and lies between you and a hot star

Kepler's third law states that a planet's orbital period, p, is related to its average (semimajor axis) orbital distance, a, according to the mathematical relationship p2=a3. Which of the following statements describe a characteristic of the solar system that is explained by Kepler's third law?

venus orbits the sun faster than earth orbits the sun inner planets orbit the sun at higher speed than outer planets