topic 5 Flashcards
where does the word planet come from?
The word planet comes from the Greek word planetes meaning wanderer
what is orbital inclination?
Not all planets follow this line exactly, they usually move a degree or two either side. This is called their orbital inclination.
As these are quite small the planets appear to move within the narrow Zodiacal band as they move around the Sun in roughly the same band/plane
what is a zodiacal band?
An extremely faint band of light that may be observed in the night-time sky along the ecliptic and which may merge into the zodiacal light.
what is retrograde motion?
Planets move eastward night by night, but sometimes they seem to reverse and go westward for a few months before returning to their usual eastward direction. This backward motion is called “retrograde motion” by astronomers.
whats it called When a planet lines up with the Sun as seen from Earth
conjunction.
whats it called When a planet is at a right angle to the Sun from the view point of earth?
it’s quadrature, western or eastern
when it’s directly opposite the Sun and in the middle is the earth?
opposition
define occulation?
An occultation happens when one object passes in front of another from an observer’s perspective, eg a solar eclipse. From a certain area on Earth, the moon passes in front of the sun and either partially or totally blocks the light. So we can say that the sun is “eclipsed” or “occulted”. A transit would be another example of this.
what are the four types of occultation?
Lunar
Asteroid
Planetary
Artificial
what are lunar occulation?
The Moon moves along the same path as the Sun and planets, called the ecliptic. Sometimes, it passes in front of distant planets and stars.
why does The Sun appears to move eastward across the sky during the year?
The Sun appears to move eastward across the sky during the year due to Earth’s orbit and its tilted axis. This movement is an illusion caused by Earth’s orbital motion and its axial tilt of 23.5 degrees compared to the ecliptic plane.
