Astronomy Final Exam: Chapters 3 & 4 Flashcards
What are the Moon phases?
New Moon, Waxing Crescent, First Quarter, Waxing Gibbous, Full Moon, Waning Gibbous, Third Quarter, and Waning Crescent
How long does it take for the Moon to complete its synodic cycle?
29.5 days
How long does it take for the Moon to complete its sidereal cycle?
27.3 days
Is the Moon larger on the horizon?
No, this is an illusion
When do lunar eclipses occur?
Only occur at full moon if the Moon’s path carries it through the shadow of Earth, sunlight is blocked, & the Moon gives temporary dim
When do solar eclipses occur?
When the Moon moves between Earth & the Sun w/ the Moon being the same angular diameter as the Sun
What is the umbra?
The region of total shadow w/ no sunlight (3x longer than the distance from earth to the Moon)
What is the penumbra?
The region of partial shadow & partial sunlight
What is a total lunar eclipse?
The Moon is COMPLETELY hidden behind Earth from the Sun causing a red glow of the Moon (Earth’s sunrise / sunset)
What is a partial lunar eclipse?
When the Moon does not pass through the center of the umbra of Earth’s shadow
What is a total solar eclipse?
The Moon covers the disk of the Sun completely
What is a partial solar eclipse?
The Moon covers only part of the Sun
Glow of the lunar eclipse is due to what?
The red tinted Moon is illuminated by some sunlight that is reflected (bent) through Earth’s atmosphere
What are elliptical orbits?
Oval-shaped path, like a slightly elongated circle
What is the Corona?
The part of the Sun visible during solar eclipses
What are Kepler’s Laws?
1.) Orbits are elliptical, with focal points of a star
2.) Orbits sweep out equal areas in equal times
3.) Square of a period equals the cube of a semimajor axis (Pr^2=aau^3)
What are ellipses?
A figure that can be drawn around 2 points, focis, in such a way that the distance from one focus to any point on the ellipse and back to the other focus equals a constant (the semi-major axis is half the longest distance)
What are eccentricities?
Half the distance between foci divided by the semimajor axis (close to 0=circular and 1=elliptical)
What was Brahe’s contribution?
-No direct contribution
-Value of his work lies in observational data & Rudolphines Tables
What was Galileo’s contribution?
-Observed Venus orbiting the Sun through phases that supported the Copernicus Model
-Use of the telescope = made observational data to make the book “Sidereus Nuncis” (The Sidereal Messenger)
