Astronomy Homeworks

Which of the following is true about a comet that is on an elliptical orbit around the Sun?

The comet's speed is greatest when it is nearest the Sun

Because of ________, we can conclude that gravity works the same way on Mars as it does on Earth.

The cosmological principle

What do we mean by accretion in the context of planet formation?

The growth of planetesimals from smaller solid particles that collided and stuck together

What conditions are required for a lunar eclipse?

The phase of the Moon must be full, and the nodes of the Moon's orbit must be nearly aligned with Earth and the Sun.

What happens during the apparent retrograde motion of a planet?

The planet appears to move westward with respect to the stars over a period of many nights.

Which is not a reason that we suspect that the extinction of the dinosaurs was caused by an explosive impact by an explosive object? a. Many dinosaur fossils are found below the K-T boundary, but none above it. b. Soot is found in the material in the K-T boundary, which probably came from fires caused by the impact. c. The material in the K-T boundary is rich in iridium d. An impact crater has been found near Mexico's Yucatan Peninsula. e. The remaining meteorite has been identified on the bottom of the Gulf of Mexico.

The remaining meteorite has been identified on the bottom of the Gulf of Mexico

Which of the following general statements about Earth's atmosphere is NOT true? a. Atmospheric pressure decreases with altitude. b. Even in low-Earth orbit, some atmospheric gas is still present. c. Atmospheric scattering of light explains why our daytime sky is bright and blue. d. The sea level temperature depends primarily on the total amount of gas in our atmosphere

The sea level temperature depends primarily on the total amount of gas in our atmosphere

Which of the following statements is false? a. Impact craters on Earth are erased over time because of erosion due to water and the recycling of its crust. b. Darker regions of the Moon's surface have fewer craters and are approximately 1 billion years younger than the lighter regions. c. Volcanoes on Mars are larger, on average, than Earth's volcanoes because Mars does not have moving continental plates. d. The surface of Venus has very few craters primarily because asteroids burn up in its thick atmosphere. e. Geological features and the chemical composition of some rocks on Mars suggest liquid water flowed on the surface in the past.

The surface of Venus has very few craters primarily because asteroids burn up in its thick atmosphere

the number 12,300 written in scientific notation is

1.23 x 10^4

If there is a first quarter Moon out tonight, approximately how long from now will it be in the third quarter phase?

2 weeks

The age of our solar system is approximately

4.6 billion years

Assume you are observing the night sky from a typical city in the United States with a latitude of +40 degrees. Using the figure below, which constellation of the zodiac would be nearest to the meridian at midnight in September?

Aquarius

According to the figure, if you were to specify your address in the universe, listing your membership from the smallest to largest physical structures, it would be

Earth, Solar System, Milky Way, Local Group, Laniakea Supercluster, the universe

At midnight it is sometimes possible to observe the crescent Moon on the meridian. true or false?

False

How does the greenhouse effect work?

Greenhouse gases transmit visible light, allowing it to heat the surface, but then absorb infrared light from Earth, trapping the heat near the surface.

What makes the North Star, Polaris, special?

It appears very near the north celestial pole.

What is the importance of the carbon dioxide (CO2) cycle?

It regulates the carbon dioxide concentration of our atmosphere, keeping temperatures moderate

If the carbon dioxide in Earth's rocks were suddenly released into its atmosphere, what would happen?

It would cause a runaway greenhouse effect

If an object is moving in a circular orbit at a constant speed, which of the following is false? a. There is an unbalanced force acting on it. b. All the above statements are true. c. Its velocity is not zero. d. Its acceleration is not zero. e. Its acceleration is zero.

Its acceleration is zero

What is the reason Mercury has so little gas in its atmosphere?

Its mass is small, It has a high temperature, its escape velocity (the lowest velocity which a body must have in order to escape the gravitational attraction of a particular planet or other object) is low, it is close to the Sun

Which of the following statements is not an observed pattern of motion in our solar system? a. Most planets orbit at the same speed. b. Most planetary orbits lie nearly in the same plane. c. Most planets rotate in the same direction in which they orbit. d. Almost all moons orbit their planet in the same direction as the planet's rotation. e. All planets orbit the Sun in the same direction.

Most planets orbit at the same speed

The figure shows the continental plates of Earth and the locations of volcanoes and earthquakes. Which statement is False? a. Earthquakes happen where two plates come together and when they spread apart. b. Earth's crust is broken up into 13 separate continental plates. c. Volcanoes occur more often where two plates are coming together rather than spreading apart. d. The Atlantic Ocean is getting smaller with time e. Southern California in the United States and Baja in Mexico are sliding northeastward relative to the rest of the North American Plate.

The Atlantic Ocean is getting smaller with time

Which of the following statements about the Moon is true?

The Moon's distance from Earth varies during its orbit.

A "light year" is a way to measure distance. true or false?

True

The Moon is constantly falling towards Earth. true or false?

True

Which of the following worlds has the greatest difference in temperature between its "no atmosphere" temperature and its actual temperature? a. Mercury b. Mars c. Venus d. Earth e. the Moon

Venus

Which of the following worlds has the most substantial atmosphere? a. the Moon b. Mercury c. Venus d. Earth e. Mars

Venus

All of the following statements are true. Which one follows directly from Kepler's third law? a. Venus orbits the Sun at a slower average speed than Mercury. b. Venus takes longer to rotate than it does to orbit the Sun. c. Venus has a thicker atmosphere than Mercury. d. Venus is more massive than Mercury.

Venus orbits the Sun at a slower average speed that Mercury.

Which of the following is farthest from the Sun? a. a comet in the Kuiper belt b. an asteroid in the asteroid belt c. Neptune d. a comet in the Oort belt e. Pluto

a comet in the Oort belt

The reason that small planets tend to lose interior heat faster than larger planets is essentially the same as the reason that

a large baked potato takes longer to cool than a small baked potato

How long is your day (i.e. from sunrise to sunset) if you live on the Moon?

a lunar month

Which of the following best describes the Milky Way Galaxy?

a spiral galaxy with a disk about 100,000 light-years in diameter and containing between 100 billion and 1 trillion stars

The thermosphere is warm because it

absorbs x-rays

Where are most of the known asteroids found?

between the orbits of Mars and Jupiter

At which lunar phase(s) are tides most pronounced (e.g., the highest high tides)?

both new and full moons

Plate tectonics is NOT responsible for a. ocean trenches b. canyons c. continental drift d. mountain ranges e. volcanoes

canyons

A planet is most likely to have tectonic activity if it has a. low internal temperature. b. high surface gravity. c. a dense atmosphere. d. low surface gravity. e. high internal temperature.

high internal temperature

Which of the following is not a factor that helps explain Earth's lack of crater compared to the Moon? a. higher density interior b. liquid water on surface c. active tectonics and volcanism d. wind erosion e. larger atmosphere

higher density interior

Heat escapes from a planet's surface into space by thermal radiation. Planets radiate almost entirely in the wavelength range of the

infrared

Why does Earth have the strongest magnetic field among the terrestrial worlds?

it is the only one that has both a partially molten metallic core and reasonably rapid rotation

There are no aurora on Venus because it

lacks a strong magnetic field

When someone on Earth observes the Moon in the full phase, someone on the Moon facing Earth observes Earth in the: (hint: draw a picture!)

new Earth phase

In science, an idea that cannot be tested is

not a scientific idea

Why are terrestrial planets denser than jovian planets?

only dense materials could condense in the inner solar nebular

What would happen if photosynthesis were to disappear on Earth?

oxygen would disappear from the atmosphere

Galileo observed all of the following. Which observation offered direct proof of a planet orbiting the Sun? a. The Milky Way is composed of many individual stars. b. patterns of shadow and sunlight near the dividing line between the light and dark portions of the Moon's face c. phases of Venus d. four moons of Jupiter

phases of Venus

Which internal energy source is the most important in continuing to heat the terrestrial planets today?

radioactivity

What was the frost line of the solar system?

the distance from the Sun where temperatures were low enough for hydrogen compounds to condense into ices, between the present-day orbits of Mars and Jupiter

According to our theory of solar system formation, which law best explains why the solar nebula spun faster as it shrank in size?

the law of conservation of angular momentum

The Orion Constellation is visible on winter evenings but not summer evenings because of

the location of Earth in its orbit

What is the primary basis upon which we divide the ingredients of the solar nebula into four categories (hydrogen/helium; hydrogen compound; rock; metal)?

the temperatures at which various materials will condense from gaseous form to solid form

Astronauts orbiting Earth in the space shuttle feel weightless in space because

they are in constant free fall around Earth

If the Moon is rising at midnight, the phase of the Moon must be

third quarter

Why would the weather become more severe as the greenhouse effect increased?

warming would increase the evaporation of the oceans, leading to more water in the atmosphere and more frequent and severe storms

Which of the following properties of an astronaut changes when he or she is standing on the Moon, relative to when the astronaut is standing on Earth?

weight