lecture1 Flashcards
(22 cards)
What occurs during a solar eclipse?
A solar eclipse occurs when the Moon’s shadow sweeps the surface of the Earth.
This phenomenon has fascinated many ancient and modern civilizations.
What is the Chinese folklore explanation for solar eclipses?
According to Chinese folklore, there is a ‘dog’ eating up the Sun during a solar eclipse.
Why are sunrises and sunsets red?
Sunlight passes through more atmosphere during sunrises and sunsets, scattering more blue light and leaving mainly orange/red light.
What causes the Moon to appear red during a lunar eclipse?
During a lunar eclipse, sunlight passes through the Earth’s atmosphere, scattering shorter wavelengths and leaving mostly red light to reach the Moon.
What is retrograde motion in astronomy?
Retrograde motion refers to the apparent westward movement of planets relative to stars for a few weeks.
What are the two conditions that must be met for an eclipse to occur?
- It must be a full moon (for a lunar eclipse) or a new moon (for a solar eclipse)
- The Moon must be at or near one of the two points in its orbit where it crosses the ecliptic plane.
What is the line of nodes in relation to the Moon’s orbit?
The line of nodes is the line joining the two points where the Moon’s orbit intersects the ecliptic plane.
What is an annular eclipse?
An annular eclipse occurs when the Moon is further away from Earth and does not completely cover the Sun, leaving a ring visible.
What is the eclipse path?
The eclipse path is the path swept out by the umbra of the Moon on the surface of the Earth during a total solar eclipse.
What types of lunar eclipses exist?
- Penumbral
- Partial
- Total
What causes lunar eclipses?
Lunar eclipses occur when the Earth blocks sunlight from reaching the Moon.
What are the phases of the Moon caused by?
The phases of the Moon are caused by different Sun-Earth-Moon orientations.
What is the difference between a sidereal month and a synodic month?
- Sidereal month: 27.3 days
- Synodic month: 29.5 days
What is the umbra in an eclipse?
The umbra is a region of total darkness during an eclipse.
What is the penumbra?
The penumbra is a region of partial darkness surrounding the umbra during an eclipse.
What happens to the Moon’s apparent size along its orbit?
The Moon’s apparent size varies along its orbit.
What is the angular size of the Moon compared to the Sun?
The angular size of the Moon is roughly the same as that of the Sun.
What is totality during a solar eclipse?
Totality is reached when the Moon completely blocks the Sun.
What color is the eclipsed Moon typically during a total lunar eclipse?
The eclipsed Moon typically has a reddish color.
True or False: Solar eclipses can occur only at new moon.
True
Fill in the blank: The Moon goes around the Earth once a _______.
month
What phenomenon explains why the sky is blue?
Scattering of light by molecules, where blue light is scattered more than red light.
