Astronomy Midterm - Eclipses
What are the two conditions which must be met in order for an eclipse to occur?
1. The phase of the moon is full (lunar eclipse) or new (solar eclipse) 2. The new or full moon occurs at a time when the moon is very close to a node.
What is the difference between the moon's umbra and penumbra?
The umbra is the central where the sunlight is completely blocked. The penumbra is the surround shadow where sunlight is only partially blocked.
How is an annular eclipse different from either a partial or a total solar eclipse?
An annular eclipse occurs when the moon is in it a part of its orbit that puts it father from the Earth and the umbra does not reach the Earth's surface
Why does the moon appear reddish during a total lunar eclipse?
Earth moves between the Sun and the Moon and cuts off the Moon's light supply. When this happens, the surface of the Moon takes on a reddish glow instead of going completely dark.
Where would you have to be on Earth to see a total lunar eclipse?
Everyone on the night side of the Earth can see a total lunar eclipse
During a solar eclipse, describe what type of eclipse you would be seeing if you were standing on Earth inside the moon's umbra, inside it's penumbra, or neither
Inside moon's umbra: total solar eclipse Inside moon's penumbra: partial solar eclipse Inside neither: No eclipse
What are the stages of a lunar eclipse? Go through what you would observe over the course of the night
Penumbral eclipse begins: Penumbral part of Earth's shadow starts moving over the Moon. Partial eclipse begins: Earth's umbra starts covering the Moon, making the eclipse more visible. Total eclipse begins: Earth's umbra completely covers the Moon and the Moon is red, brown or yellow in color. Maximum eclipse: This is the middle of the total eclipse. Total eclipse ends: Earth's umbra starts moving away from the Moon's surface. Partial eclipse ends: Earth's umbra completely leaves the Moon's surface. Penumbral eclipse ends: Eclipse ends and Earth's shadow completely moves away from the Moon.
Explain how the nodes of the moon's orbit determine whether we will see an eclipse or not each month?
Since the moon's orbit is slightly inclined to the ecliptic plane, the moon spends most of its time either above or below this surface. It crosses through this surface only twice during each orbit: once coming out and once going back in. These two points are called the nodes and they lie along a nearly straight line with the Sun and Earth. Eclipses can only occur during these periods.
Where does the moon have to be in orbit for an annular eclipse to occur?
The moon has to be in a part of its orbit that puts it farther from the Earth
Name the three types of lunar eclipses and what each looks like from Earth
Total Lunar Eclipse: When sun, earth, and moon are perfectly aligned. Moon is red Partial Lunar Eclipse: When only part of full moon passes through the umbra. Most of moon is dark. Penumbral Lunar Eclipse: When moon passes through only Earth's penumbra. Part of moon is dark.
What are the three types of solar eclipses and what do each look like from Earth?
Total solar eclipse - Occurs in the umbra, moon completely overlaps the sun Annular Eclipse - When the moon's umbral shadow does not reach the earth and a ring of sunlight surrounds the earth. Partial solar eclipse - Occurs in the lighter area surrounding the area of totality. Moon partially overlaps the sun.
Why do we not have an eclipse every time the moon is full or new?
We don't have a eclipse every time the moon is full or new because the new or full moon must occur at a time when the moon is very close to a node.
If you were standing on the moon during a lunar eclipse, what would you see?
You would see the Earth eclipse the Sun.
