chapter 1 homework

When a thin crescent of the Moon is visible just before sunrise, the Moon is in its

waning phase

Listed is an observable characteristic of an equinox or solstice in the continental United States (which means temperate latitudes in the Northern Hemisphere). What is the corresponding equinox or solstice to the characteristic? - "The noontime Sun casts the longest shadows"

winter solstice

Listed is an observable characteristic of an equinox or solstice in the continental United States (which means temperate latitudes in the Northern Hemisphere). What is the corresponding equinox or solstice to the characteristic? - "sunset occurs at its farthest point south of due west for the year"

winter solstice

Listed is an observable characteristic of an equinox or solstice in the continental United States (which means temperate latitudes in the Northern Hemisphere). What is the corresponding equinox or solstice to the characteristic? - "the Sun crosses the meridian 23.5 degrees lower in altitude than the celestial equator"

winter solstice

Calculate (3 × 10 ^ 4 ) + 10 ^ -1 .

3.00001 x 10 ^ 4 OR 30,000.1 because 10 ^ -1 = .1

Calculate (1.99 × 10 ^ 30) / (5.98 × 10 ^ 24).

3.33 x 10 ^ 5 OR 333,000

Write the following numbers in "normal" numerical form: 3.16 × 10 ^ 7 2.998 × 10 ^ 5 6.67 × 10 ^ -11 2 × 10 ^0.

31,600,000 299,800 .0000000000667 2

The following figures show a top view of Earth, sunlight, and six different positions of the Moon as it orbits Earth. Note that the distances shown are not drawn to scale. Rank each of the six lunar positions from left to right based on the amount of the Moon's illuminated surface that is visible from Earth, from greatest to least. (If two diagrams have an equal amount of illumination as seen from Earth, put one on top of the other.)

- full - waning gibbous - quarter(s) - waxing crescent - new

Shown following are five different phases of the Moon as seen by an observer in the Northern Hemisphere. Imagine that tonight the Moon is in the waxing gibbous phase (as shown at the far left (labeled "first") in the following ranking box). Rank the pictured phases from left to right based on the order in which you would see them over the next four weeks, from first seen to last.

- waning gibbous - third quarter - waning crescent - waxing crescent - first quarter

Calculate (3.16 × 10 ^ 7) × (2.998 × 10 ^ 5).

9.47 x 10 ^ 12 OR 9,470,000,000,000

A long, thin cloud that stretched from directly overhead to the western horizon would have an angular size of

90 degrees

One way to triangulate the distance to many remote objects, such as stars, is to observe the shifts in their location relative to more distant background objects. This apparent shifting of an object's location with respect to the background objects is known as parallax. Parallax is represented in the figure, where the top image shows the parallax shift that is observed along a baseline that runs from one side of Earth to the other. The bottom two images show what the observer sees from opposite sides of Earth. Using triangulation, the distance to the object can be calculated with simple trigonometric relations.

1. As the distance to the object increases, parallax decreases. 2. As the size of baseline increases, parallax increases 3. As the distance to background objects increases, parallax remains the same Measuring the parallax of a foreground object with respect to a more distant background of objects allows for the use of geometric triangulation to determine the distance to the foreground object. The key components include the baseline over which parallax is measured, the parallax that is measured, and the distance that is determined. Astronomers have used this technique to determine distances to the Moon and planets in the solar system. Parallax has also been used to determine distances to stars, but a much larger baseline involving Earth's orbit around the Sun is necessary to accurately measure parallax.

Suppose that instead of being inclined to Earth's orbit around the Sun, the Moon's orbit was in the same plane as Earth's orbit around the Sun. (Click "Show Moon with flat orbit" to see this situation.) In this hypothetical situation, approximately how many solar eclipses would occur each year?

12-If the Moon orbited Earth in the same plane that Earth orbits the Sun (the ecliptic plane), we would have a solar eclipse at every new moon. Because there are about twelve new moons in a year, we would have twelve solar eclipses. Of course, this isn't what really happens. Continue to Part B to study the real situation.

In reality, the Moon's orbit about Earth is tilted (by about 5°) with respect to Earth's orbit about the Sun. As a result, the actual number of solar eclipses that occur each year is approximately _____.

2 - There are generally two periods of time each year when eclipses are possible — the "eclipse seasons" — and there is a solar eclipse of some type (partial, total, or annular) during each of these eclipse seasons. (Because the time between eclipse seasons is less than six months, in some years there is a third eclipse season and hence a third solar eclipse.)

If you could change the layout of the solar system, which of the following would cause a lunar eclipse to occur at least once every month in this hypothetical situation?

Change the Moon's orbital plane so it is in the same plane as Earth's orbit around the Sun.

Geometric reasoning can be used to measure distances both on Earth and in space. Surveyors on Earth and astronomers both use the geometric technique of triangulation to determine the distances and sizes of remote objects. In order to determine the distance using the triangulation method, a few key geometric components must be known. Once the baseline and the sightline angles are determined, then the distance can be calculated with simple geometric reasoning.

Surveyors use triangulation to measure distances to objects on Earth. The same technique can also be used to determine the distance to nearby astronomical objects. Astronomers use Earth's diameter as the baseline in the triangulation method to measure distances to planets and other objects in our solar system.

What conditions must exist for a lunar eclipse to occur?

The phase of the Moon must be full and the Moon must be passing through Earth's orbital plane.

What conditions must exist for a solar eclipse to occur?

The phase of the Moon must be new and the Moon must be passing through Earth's orbital plane.

In Figure 1.28 in the textbook ("Triangulation"), using a longer baseline would result in

a smaller angle at point B.

Consider the Moon and Sun. Their angular diameters are both equal to about .5 degree. If the Sun is roughly 400 times more distant than the Moon, how much bigger is the Sun's diameter than the Moon's?

about 400 times bigger - Proportional reasoning shows that the Sun, being about 400 times more distant than the Moon, must be about 400 times larger in order to have the same angular diameter as the Moon, because angular distance is proportional to diameter divided by distance: (Diameter×(57.3 degrees))Distance=Angular Diameter

According to Figure 1.15 in the textbook ("The Zodiac"), in January the Sun is in the constellation According to Figure 1.15 in the textbook ("The Zodiac"), in January the Sun is in the constellation

aquarius

Listed is an observable characteristic of an equinox or solstice in the continental United States (which means temperate latitudes in the Northern Hemisphere). What is the corresponding equinox or solstice to the characteristic? - the Sun has declinatio of 0 degree today, but will have a negative declination tomorrow

fall equinox

Today, distances to stars are measured by

geometry

If Earth orbited the Sun in 9 months instead of 12, then, compared with a sidereal day, a solar day would be

longer

If the Moon's orbit were a little larger, solar eclipses would be

more likely to be annular.

Listed following are the declinations of five different stars. Rank these declinations from left to right based on the maximum altitude (on the meridian) each star reaches for an observer at latitude 60°N, from lowest altitude (nearest the horizon) to highest altitude (farthest above the horizon). - dec = -5 degrees - dec = -20 degrees - dec = +10 degrees - dec = +0 degrees - dec = +30 degrees

nearest the horizon - dec = -20 degrees - dec = -5 degrees - dec = +0 degrees - dec = +10 degrees - dec = +30 degrees farthest above the horizon

Listed following are the latitudes of several locations on Earth. Rank these latitudes from left to right based on the maximum altitude (on the meridian) at which the celestial equator passes through the local sky, from lowest altitude (nearest the horizon) to highest altitude (farthest above the horizon). - latitude 70 degrees N - latitude 40 degrees N - latitude 50 degrees N - latitude 10 degrees N - latitude 30 degrees N

nearest the horizon - latitude 70 degrees N - latitude 50 degrees N - latitude 40 degrees N - latitude 30 degrees N - latitude 10 degrees N farthest above the horizon

Listed following are the latitudes of several locations on Earth. Rank these latitudes from left to right based on the maximum altitude (on the meridian) at which you would see a star with a declination of 0°, from lowest altitude (nearest the horizon) to highest altitude (farthest above the horizon). - latitude 70 degrees N - latitude 10 degrees N - latitude 30 degrees N - latitude 50 degrees N - latitude 40 degrees N

nearest the horizon - latitude 70 degrees N - latitude 50 degrees N - latitude 40 degrees N - latitude 30 degrees N - latitude 10 degrees N farthest above the horizon

The vernal equinox is now just entering the constellation Aquarius. In what constellation will it lie in the year A.D. 10000?

scorpio

Each item following represents an amount of time. Recall from your reading that "sidereal" refers to events that are timed with respect to the distant stars, and "synodic" refers to special alignments of astronomical bodies, such as the Earth, Moon, and Sun. Rank the items from left to right in order of the amount of time they represent, from shortest time to longest time. If two items represent equal amounts of time, show this equality by dragging one on top of the other.

shortest time - sidereal day // one rotation of earth on its axis - solar day - sidereal month // one moon orbit around earth - synodic month // one full cycle of moon phases longest time The first three times relate to Earth's rotation: A sidereal day is equal to Earth's rotation period of about 23 hours and 56 minutes; our 24-hour solar day is slightly longer because Earth is moving around its orbit at the same time that it rotates. The last four items are related to the Moon's orbit around Earth, The Moon's true orbital period is the sidereal month, which is about 27 1/2 days. The synodic month, which is equal to the time from one new moon to the next, is longer (about 29 1/2 days) because Earth and the Moon are moving around the Sun at the same time that the Moon orbits Earth.

Listed is an observable characteristic of an equinox or solstice in the continental United States (which means temperate latitudes in the Northern Hemisphere). What is the corresponding equinox or solstice to the characteristic? - "The sun rises due east today, but will rise slightly north of due east tomorrow"

spring equinox

If the Moon orbited Earth twice as fast, but in the same orbit, the frequency of solar eclipses would

stay the same

Listed is an observable characteristic of an equinox or solstice in the continental United States (which means temperate latitudes in the Northern Hemisphere). What is the corresponding equinox or solstice to the characteristic? - "longest day (most daylight) of the year"

summer solstice

Listed is an observable characteristic of an equinox or solstice in the continental United States (which means temperate latitudes in the Northern Hemisphere). What is the corresponding equinox or solstice to the characteristic? - "the noontime Sun reaches its highest point of the year"

summer solstice

Listed following are a series of statements that each make a claim. Classify these as either testable by accepted methods of science or non-testable by accepted methods of science. Be sure to note that this question does not ask whether a statement would pass or fail a test; it only asks whether it is testable in principle. - Hurricane Katrina was an act of God - bacteria acquire resistance to antibiotics through changes in their DNA - Earth orbits the Sun every 365.25 days - Mars once had liquid water on its surface - Vince Young is the greatest quarterback of all time - people born under the sign of Sagittarius are twice as likely to be teachers as anyone else - there will be a solar eclipse next tuesday at 11 am

testable by science - bacteria acquire resistance to antibiotics through changes in their DNA - Earth orbits the Sun every 365.25 days - Mars once had liquid water on its surface - people born under the sign of Sagittarius are twice as likely to be teachers as anyone else - there will be a solar eclipse next tuesday at 11 am not testable by science - Hurricane Katrina was an act of God - Vince Young is the greatest quarterback of all time