Question 1

The one significant observation Galileo made through his home-built telescope that convinced him that the planets revolved around the Sun was the:

Accepted Answer

Galileo's observation of Venus following a cycle of phases, from crescent through quarter and gibbous phases to full, was proof that Venus must be orbiting the Sun, as the phases could only be explained by Venus orbiting between the Earth and the Sun. This observation supported the heliocentric model of the solar system proposed by Copernicus, and convinced Galileo that the planets do indeed revolve around the Sun.

Question 2

As Venus orbits the Sun,its angular size as viewed from Earth appears to change by what factor,from smallest to largest? (See Figure 2-10,Comins,Discovering the Essential Universe,6th ed.)

Accepted Answer

The angular size of Venus changes by a factor of 5.8 from its smallest to largest as it orbits the Sun, due to its varying distance from Earth.

Question 3

When viewed from Earth,which of the following planets shows the GREATEST change in angular size over one planetary orbit?

Accepted Answer

Venus has the shortest orbital period of about 225 Earth days and is also the closest planet to Earth, which means that it undergoes the greatest change in angular size during one planetary orbit. This is because the apparent size of a planet is directly proportional to its distance from Earth, and Venus comes closest to Earth during its inferior conjunction, which occurs about every 584 days. During this time, Venus appears as a large "dazzling star" in the evening or morning sky, which is why it has been known as the "Morning Star" or the "Evening Star" in ancient times. In contrast, Mercury has a longer orbital period but is much smaller and farther away, while Uranus has a longer orbital period and a smaller apparent size due to its greater distance from Earth. Jupiter has a relatively large apparent size but its orbital period is much longer than Venus, so it does not show as much variation in angular size over one planetary orbit.

Question 4

Galileo's early observations of the sky with his newly made telescope included the discovery of:

Accepted Answer

Galileo's observation of the phases of Venus provided evidence for the heliocentric model of the solar system proposed by Copernicus, which placed the Sun at the center and the planets revolving around it.

Question 5

The angular diameter of Venus appears largest when its phase is:

Accepted Answer

The angular diameter of Venus appears largest when its phase is crescent. This is because when Venus is in crescent phase, it is closer to Earth and appears larger in the sky.

Question 6

In the geocentric model of the solar system,which one of the following phases of Venus should be visible from Earth?

Accepted Answer

In the geocentric model of the solar system, Venus goes through phases like the Moon as seen from Earth. Since the geocentric model places Earth at the center of the solar system, Venus can only have the new phase when it is between Earth and the Sun. Therefore, the answer is B. Full phase would be when Venus is on the opposite side of the Sun from Earth, while gibbous phases occur when Venus is at other positions in its orbit.

Question 7

Which of the following observations of the motions of the large moons of Jupiter did Galileo find MOST significant?

Accepted Answer

Galileo's most significant observation was that the moons farther from Jupiter had longer periods, just as Copernicus had discovered for the planets around the Sun. This supported the Copernican model of the solar system where the planets revolve around the Sun rather than the Earth, which was a major shift in thinking at the time. The other options were also important, but not as crucial in supporting the heliocentric model.

Question 8

Galileo observed Venus to go through a full range of phases.Which other planet should also display a full range of phases when viewed from Earth?

Accepted Answer

Like Venus, Mercury's orbit is between the Sun and the Earth. Therefore, when viewed from Earth, it is possible to see the planet go through a full range of phases, including crescent, half, and gibbous phases. Other planets, such as Mars and Jupiter, do not exhibit a full range of phases when viewed from Earth because their orbits are outside of Earth's orbit.

Question 9

What did Galileo NOT observe with his new telescope?

Accepted Answer

Galileo did not observe Neptune as he did not have a powerful enough telescope to see it during his lifetime.

Question 10

How many moons of Jupiter did Galileo see?

Accepted Answer

Galileo observed four of Jupiter's largest moons (Io, Europa, Ganymede, and Callisto) using his telescope, which allowed him to see much farther and clearer than with the naked eye.

Question 11

Venus shows changes in angular size and also shows phases similar to the phases of the Moon.According to Galileo,who first saw the phases,these observations showed that Venus:

Accepted Answer

The observations of the changes in angular size and phases of Venus suggest that it orbits the Sun, and not Earth. This was a key observation in support of the heliocentric model of the solar system.

Question 12

In the heliocentric model of the solar system,which of the following phases of Venus should NOT be visible from Earth?

Accepted Answer

In the heliocentric model, all phases of Venus, including full, gibbous, and new, are visible from Earth as Venus orbits the Sun.

Question 13

Which of the following statements CORRECTLY states the significance of Galileo's observation that Venus shows phases?

Accepted Answer

The observation of Venus showing phases supported the heliocentric theory because the phases were correlated with angular size, which is what would be expected if Venus was orbiting the Sun rather than the Earth. This observation provided evidence against the geocentric model and helped to solidify the heliocentric model of the solar system.

Question 14

What did Galileo see when he observed Venus through his telescope?

Accepted Answer

Galileo observed that Venus went through phases like the Moon's, which provided evidence for the heliocentric model of the solar system.

Question 15

In the geocentric model of the solar system,which of the following phases of Venus should NOT be visible from Earth?

Accepted Answer

In the geocentric model, Venus is always between Earth and the Sun, so it cannot show a full phase.

Question 16

What did Galileo see when he observed Venus through his telescope?

Accepted Answer

Galileo observed that Venus exhibits phases similar to the Moon, and its largest angular diameter occurs when it is in the crescent phase, supporting the heliocentric model of the solar system.

Question 17

According to Galileo's observations of Venus,when Venus is at full phase,its angular size:

Accepted Answer

The answer of According to Galileo's observations of Venus,when Venus...

Question 18

Viewed from Earth,the LARGEST angular diameter of Venus occurs when it is at which phase?

Accepted Answer

Venus has the largest angular diameter when it is at the new phase because it is closest to Earth at this point in its orbit, appearing larger in the sky.

Question 19

At which point,as seen from Earth,will a planet appear exactly half-lit (looking like the first quarter or last quarter Moon)? (It may help to draw a diagram and show the sunlit side of the planet on it.)

Accepted Answer

At greatest elongation, the planet is at its maximum angular distance from the Sun as seen from Earth, making it appear half-lit, similar to the first or last quarter Moon.

Question 20

A planet will be observed (through a telescope)to have a crescent shape whenever it is close to which point as seen from Earth?  (It may help to draw a diagram and show the sunlit side of the planet on it.)

Accepted Answer

A planet will appear to have a crescent shape when it is in inferior conjunction, which means it is between the Sun and Earth. The sunlit side of the planet will be facing away from Earth, so only a crescent shape will be visible.

Quiz 2: Gravitation and the Waltz of the Planets

The one significant observation Galileo made through his home-built telescope that convinced him that the planets revolved around the Sun was the:

As Venus orbits the Sun,its angular size as viewed from Earth appears to change by what factor,from smallest to largest? (See Figure 2-10,Comins,Discovering the Essential Universe,6th ed.)

When viewed from Earth,which of the following planets shows the GREATEST change in angular size over one planetary orbit?

Galileo's early observations of the sky with his newly made telescope included the discovery of:

The angular diameter of Venus appears largest when its phase is:

In the geocentric model of the solar system,which one of the following phases of Venus should be visible from Earth?

Which of the following observations of the motions of the large moons of Jupiter did Galileo find MOST significant?

Galileo observed Venus to go through a full range of phases.Which other planet should also display a full range of phases when viewed from Earth?

What did Galileo NOT observe with his new telescope?

How many moons of Jupiter did Galileo see?

Venus shows changes in angular size and also shows phases similar to the phases of the Moon.According to Galileo,who first saw the phases,these observations showed that Venus:

In the heliocentric model of the solar system,which of the following phases of Venus should NOT be visible from Earth?

Which of the following statements CORRECTLY states the significance of Galileo's observation that Venus shows phases?

What did Galileo see when he observed Venus through his telescope?

In the geocentric model of the solar system,which of the following phases of Venus should NOT be visible from Earth?

What did Galileo see when he observed Venus through his telescope?

According to Galileo's observations of Venus,when Venus is at full phase,its angular size:

Viewed from Earth,the LARGEST angular diameter of Venus occurs when it is at which phase?

At which point,as seen from Earth,will a planet appear exactly half-lit (looking like the first quarter or last quarter Moon) ? (It may help to draw a diagram and show the sunlit side of the planet on it.)

A planet will be observed (through a telescope) to have a crescent shape whenever it is close to which point as seen from Earth? (It may help to draw a diagram and show the sunlit side of the planet on it.)