Astronomy 127

Scientific Method

1. First observe something that you want to understand. gather data about it
2. Make a hypothesis about what is happening
3. test the hypothesis by making predictions. Modify the hypothesis according to results from new experiments. mature it into a theor


an educated guess based on all the knowledge you have


a well-developed set of hypotheses


law is a physical description. It does not include an explanation of what is observed. tells what is happening not why


a plausible scenario of what is happening


-Latin for group of stars
-88 constellations in the sky
-ancient people used them to preserve mythology
-orion is the dominant winter constellation
-stars of constellations are tens or hundreds of light years apart. placement is random
-use constellations


-study of the universe

moon phases

-moon like earth is always half in shadow and in light
-as the moon orbits, we see different portions of the light and dark sides
-full moon-waning gibbous, third quarter, waning crescent, new moon, waxing crescent, first quarter, waxing gibbous

new moon

moon is between earth and sun

full moon

Earth is between moon and sun


An arc drawn on a map between the North and South poles.

-when does full moon rise
-When is the full moon on the meridian
-when does full moon set


-when does first quarter moon rise
-When is the first quarter moon on the meridian
-when does first quarter moon set


-when does new moon rise
-When is the new moon on the meridian
-when does new moon set


-when does third quarter moon rise
-When is the third quarter moon on the meridian
-when does third quarter moon set


lunar rotation

-rotation of moon is same rate as revolution of moon about Earth. there is no permanently dark side

moon orbital plane

-moon doesn't orbit in the Earth-sun plane. its orbit is tipped by 5 degrees
-moon passs above or beneath the sun, but when the line of nodes aligns with the sun we get an eclipse

lunar eclipse

the blocking of sunlight to the moon that occurs when Earth is directly between the sun and the moon
-only when moon is full (behind earth. sun, earth, moon) and within the umbra

types of lunar eclipses

-total eclipse
-partial lunar eclipse
-penumbral eclipse