Mastering Astronomy 101- Chapter 3

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.

Tycho Brahe's contribution to astronomy included:

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

Which of the following is not true about a scientific theory?

A theory is essentially an educated guess.

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

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.

According to Kepler's 3rd Law:

Jupiter orbits the Sun at a faster speed than Saturn.

When would you expect to see Venus high in the sky at midnight?

Never

Which of the following is not true about scientific progress?

Science advances only through the scientific method.

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

The planet actually goes backward in its orbit around Earth.

In Ptolemy's Earth-centered model for the solar system (not shown), 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.

In Ptolemy's Earth-centered model for the solar system (not shown), 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

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.

When Einstein's theory of gravity (general relativity) gained acceptance, it demonstrated that Newton's theory had been

incomplete.

Galileo's contribution to astronomy included:

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

What is Eris's (orbits the Sun every 557 years) average distance (semimajor axis) from the Sun?

67.7 AU

How does Eris's (orbits the Sun every 557 years) average distance compare to that of Pluto?

Eris orbits farther than Pluto.