Earth Science Chapter 22 BJU 5th ed

astronomical unit (AU)

What is the name for the average distance from the Earth to the Sun, about 93 million miles (150 million kilometers).

solar spectrum

The range of all the different wavelengths (colors) of light emitted by the Sun.

nuclear fusion

The process in the Sun’s core where hydrogen atoms combine to form helium, releasing a huge amount of energy.

Photosphere

The visible surface of the Sun from which light is emitted.

Chromosphere

A thin layer of the Sun’s atmosphere just above the photosphere, seen as a reddish glow during a solar eclipse.

Corona

The outermost layer of the Sun’s atmosphere, visible as a white halo during a total solar eclipse.

Prominence

A large, bright loop of gas that extends from the Sun’s surface, often looping back due to magnetic forces.

solar wind

A stream of charged particles released from the upper atmosphere of the Sun that travels through space.

Sunspot

A dark, cooler area on the Sun’s surface caused by magnetic activity.

sola flare

A sudden, intense burst of radiation from the Sun’s surface, caused by magnetic energy being released.

Ray

Bright streaks of material that radiate from a crater on the Moon, formed by impact explosions.

Mare

A large, dark plain on the Moon’s surface formed by ancient lava flows; Latin for “sea.”

Rille

A long, narrow valley or trench on the Moon’s surface, often formed by lava flow or collapsing ground.

Ecliptic

The apparent path the Sun takes through the sky over the course of a year, also the plane of Earth’s orbit.

Revolution

The movement of one object around another, like the Earth orbiting the Sun.

Rotation

The spinning of a planet or moon on its axis.

lunar phase

The changing appearance of the Moon from Earth, caused by the Moon’s position relative to the Earth and Sun.

Terminator

The dividing line between the lit and dark sides of the Moon or a planet.

solar eclipse

An event where the Moon passes between the Earth and the Sun, blocking sunlight from reaching Earth.

lunar eclipse

An event where the Earth passes between the Sun and the Moon, casting a shadow on the Moon.

The distance between the Earth and the Sun.

What is an astronomical unit (AU) defined as?

Visible light.

What type of electromagnetic energy does the sun produce that is visible to the human eye?

Red light has longer wavelengths.

What type of light from the sun appears deep red, and why?

The sun is mostly composed of hydrogen.

What is the sun mostly composed of?

Sunspots form due to magnetic activity that causes cooler areas on the sun’s surface.

What do astronomers believe causes sunspots to form on the sun’s surface?

Solar flares or coronal mass ejections (CMEs).

What are severe solar storms that can disrupt telecommunications on Earth called?

The New Moon phase.

Which moon phase marks the beginning of the lunar month?

Most likely because it spins slowly on its axis, creating little equatorial bulging.

Why does the moon have a nearly perfect spherical shape?

The Moon's average density is approximately 3.34 g/cm³, while Earth's average density is about 5.52 g/cm³. This means the Moon is significantly less dense than Earth, with its density being roughly 60% of Earth's density

How does the average density of the moon compare to Earth’s density?

The moon’s surface gravity is about one-sixth of Earth’s gravity.

How does the moon’s surface gravity compare to Earth’s gravity?

The moon has a very thin atmosphere because it lacks the necessary mass to hold a thick atmosphere.

Why does the moon have a very thin atmosphere?

Lunar mountains appear to be formed by ancient impacts and volcanic activity.

What do lunar mountains appear to be formed by?

The apparent path is called the ecliptic.

What is the path that the sun follows through the stars, as seen from Earth?

The moon rotates once during each revolution around the Earth.

How many times does the moon rotate during one revolution around the Earth?

Waxing.

What is the phase of the moon called when it is getting brighter each night?

Waning.

What phase comes after the full moon, when the moon starts to get darker each night?

Full moon.

What is the phase of the moon called when the entire face of the moon is illuminated?

A common year.

What do we call the 365 days from January 1st to December 31st?

The moon must be in the new moon phase during a total solar eclipse.

In which phase must the moon be during a total solar eclipse?

Photosphere.

What is the visible surface of the sun called?

Chromosphere.

What is the layer of the sun’s atmosphere located just above the photosphere?

Radiative zone.

What is the layer of the sun where energy is transferred through radiation?

Perihelion.

What is the closest point in a planet's orbit to the sun?

Core.

What is the central region of the sun, where nuclear fusion occurs?

Corona.

What is the outermost layer of the sun’s atmosphere that extends far into space?

Mare.

What is the large, flat, dark region on the moon’s surface, made of ancient lava flows?

Crater.

What is the bowl-shaped depression on the moon’s surface created by a meteor impact?

Plasma.

What is the state of matter where atoms are ionized and become electrically charged?

Rille.

What are the long, narrow valleys or channels on the moon’s surface?

Ejecta.

What is the material that is thrown out of a crater during an impact event?

Ray.

What is the bright, narrow streak that extends outward from a lunar crater?