BJU Earth Science Fourth Edition Chapter 22 Review

How do astronomers know about the sun's composition?

Astronomers have a tool called a spectroscope that "fingerprints" light from stars and planets. When an element becomes hot enough, it gives off separate, distinct colors that only that element produces. The sun's emission spectrum helps astronomers catalog which elements are present at its visible surface.

How does the sun's activity affect the earth?

At the peak of a sunspot cycle, the sun emits more energy, even though the sunspots are cooler and darker. The opposite is true at times of fewest sunspots. These have small but measureable effects on Earth's climate. During active periods, solar flares can damage. The ozone layer can thin, allowing too much UV light past the atmosphere. Massive solar flares can disrupt radio communications on Earth and damage satellites and electrical power grids.

(True or False) Dramatic changes in the sun's magnetic field at its surface seem to produce sunspots, solar flares, and prominences.

False

(True or False) During a lunar eclipse, the moon blocks the sun's light.

False

(True or False) Our eyes can detect yellow light waves.

False

(True or False) The earth's orbit is inclined 23.5° to the ecliptic.

False

(True or False) The moon has no atmosphere.

False

(True or False) The nearly perfect spherical shape of the moon is an indication that it is spinning very rapidly.

False

(True or False) The simplest method to compute a year is to count a certain number of new moons.

False

(True or False) You would weigh half as much on the moon as you do on Earth if you were dressed the same way in both.

False

Where does the sun's energy come from? How is it released into space?

In the core, nuclear reactions generate the sun's energy. Physicists believe that nuclei of hydrogen atoms combine under intense heat and pressure to form the nuclei of helium atoms in a process called nuclear fusion. This process releases tremendous amounts of energy. After leaving the core, concentrated electromagnetic energy moves outward through the radiative zone. Once coming out of there, they enter the convective zone. Here, the energy gets to the sun's surface. There are also things like plages, faculae, solar wind, solar flares, and prominences that contribute to releasing energy

Can we see most of the sun's electromagnetic energy? Explain.

No. We can only see the small visible spectrum. Most of the sun's energy is not visible to the human eye.

Make a sketch of the current model of the moon's interior. Label each section.

On separate sheet of paper

Describe the general shape of the moon's orbit around the earth and any special positions in its orbit.

The moon revolves around the earth as it rotates on its own axis. The plane of the moon's orbit is tilted 5.4° to the ecliptic plane. The moon's orbit is an ellipse. The moon orbits in a counterclockwise direction. Sometimes, solar eclipses and lunar eclipses can occur. Solar eclipses occur when the moon completely covers the sun's disk. A lunar eclipse occurs when the earth blocks the sun's light that normally shines on the moon.

What causes the apparent motion of the sun along the ecliptic?

The sun is a star snuggled into a gap between two arms of the Milky Way galaxy. The galaxy slowly turns like a giant pinwheel. Each star travels in its own orbit around the center of the galaxy.

How is the sun a special star?

The sun is our largest energy source. It heats our planet and gives us seasons. It helps plants grow. It gives living things energy.

What kinds of things happen in the sun's atmosphere?

The temperature is extremely high in the sun's atmosphere. Pointed masses of hot plasma called spicules leap 6000 miles or more from the chromosphere's surface. The clouds in the chromosphere are called plages and faculae. There are also prominences in the corona. The corona eventually becomes the solar wind.

Describe the appearance of the sun's photosphere.

The visible surface of the sun is the photosphere. It's a fluid. It looks like a seething pot of boiling water as mounds of hot plasma rise from the sun's interior. These mounds are called granules. You can also find sunspots and solar flares here.

Why do craters, mountains, and even astronauts' footprints on the moon remain crisp and clear over time?

There is no weathering by rain or wind.

Why don't lunar eclipses occur with every full moon?

They don't happen at every full moon because of the tilt of the moon's orbit.

Why are earth tides much smaller than ocean tides?

Tidal forces deform the earth's crust just as they do the oceans. Earth tides don't work quite the same way as ocean tides. The gravitational pulls of the moon and sun set up various kinds of oscillations in the crust that don't match their daily pulls as the earth rotates. Many factors between the sun and the moon, such as the earth's gravity's pull on the moon at its apogee and the force of the moon exerted on earth and vice versa.

(True or False) A solar eclipse can occur only at a new moon.

True

(True or False) The hottest part of the sun itself is its corona.

True

(True or False) The moon is slowly drifting away from the earth.

True

(True or False) The most common element in the sun is hydrogen.

True

(True or False) The sun rotates faster at its equator than it does at the poles.

True

(True or False) The sun's motion through the heavens as viewed from Earth is an optical illusion.

True

(True or False) you can still see the moon during a lunar eclipse.

True

How would life on Earth be different if there were no moon?

We would have no light at night. We wouldn't have tides. We wouldn't be able to observe the sun as well as we could with it. We wouldn't have our months the same.

How would you determine, by observing from the Northern Hemisphere, whether a crescent moon is waxing or waning?

When a crescent moon is waxing, the dark area seems smaller. When it is waning, the dark area seems larger.