Summary

Summary of the Units

By:Mike (Yaobin Ma)

Class: L

This unit, I learned that astronomy is the study of stars. Geocentric model is a theory that found by Ptolemy that shows Earth is on the middle of the universe. But this theory was wrong, soon Copernicus found out that sun should be at the middle of the universe and this is the theory of Heliocentric model.

I also learned rotation, the spinning of it’s axis, it takes around 29 days for moon to run a complete rotation. Polaris is a north star that help people configure direction in the past and even today. The world is split into North hemisphere and South hemisphere, they both contain a pole, which is the coldest place in the world, since they always get indirect sunlight Although equator is the hottest place in the place because it always get direct sunlight.

As for revolution, it’s similar to rotation. It takes the Earth around 365 days to make a complete revolution by orbiting on it’s axis. Of course there is not only Earth in the universe, there are sun, moon and many many constellations. With the moon and sun, there will be a rare thing that will occur: solar eclipse and lunar eclipse, that when moon is covered by sun or sun is covered by moon. And with the distance between it, perihelion and aphelion had created to explain the differences. Also, solstice are split into summer and winter. Summer solstice happens between December 20 and December 23 in Southern Hemisphere and between June 20 and June 22 in the Northern Hemisphere. Winter Solstice happens between December 21 to 22 in the Southern hemisphere and June 21 to 22 in Northern hemisphere.

Lunar revolution is spinning on it’s axis. It take around 27-29 days to finish a rotation. There is total lunar eclipse and partial lunar eclipse. the differences are that when total is completely cover like umbra, and partial is only part of it got covered like penumbra. This theory goes for solar total eclipse and solar partial eclipse.

Phase of the moon is how the moon look like in different forms. Waning is a process that decrease part of the moon and waxing is increase the part of the moon. The phrase of the moon contain: new moon, gibbous moon, quarter moon, crescent moon, and full moon.

The tide in here is very interesting. It contain spring and neap tide. There are low and high tide, it cause by the gravitation of the moon, when moon, sun and earth line on at one line, it will become high tide. When moon, sun and earth line at 90 degree, it will have a low tide, plus all ocean level will be the same at the neap tide.

Time zone is a topic that teaches us the different time in different places. longitude is a line to specified east west to east position. A prime meridian is a longitude that located at 0 degree. The International Date Line is an imaginary line that go through North pole to South pole. Greenwich  Mean Time is a time that doesn't change with the seasons.