Jennifer Blazejack Lecture September 5

Celestial Sphere

Milky Way Galaxy

Ecliptic

Angular distance/size

Latitude/ Longitude

Solstice/Equinox

Solar/Lunar Eclipses

Moon Phases

Zenith, etc.

Introduction

We saw the power point and video for Chapter 2. We were also given a quiz and how Life in the Universe can be a subject for the term paper (all we have to do is ask for the book). The following is what was discussed in class.

Celestial Sphere

Is around the Earth and it has an equator called the Celestial Equator. The Celestial Sphere makes it seem that all stars are there when the stars actually lie in different distances. It’s important to remember the degree 23 ½ because that helps to keep one side of the world from being winter all the time or summer all the time.

Milky Way Galaxy

A band of light that makes a circle around the Celestial Sphere (the globe passed around in class).

Ecliptic

The Sun’s path and it is also in the Celestial Sphere.

Angular Distance/Size

Angular distance can be cut down into arcminutes and arcseconds (1˚ can be broken down into 60 arcminutes). You can use your hand to get an idea of angular distance. All you have to do is stretch out your arm and use a finger to measure degrees (one finger equals 1˚). To get the angular size of an object you have to follow a formula:

physical size × 360˚

2П × distance

Latitude/Longitude

Latitude measures north to south and longitude measures east to west. The sky varies with latitude and not longitude. Latitude can give a sense of time when lost, but without longitude many lost people die.

Solstice/Equinox

Solstice in Latin means “sun stops” and Equinox in Latin means “equal night”. There is a summer and winter solstice, and a spring and fall equinox. Human sacrifices were made back in ancient Mexico tell help the Sun come back into our night sky. The axis tilt is the key to the changing of seasons. Earth does not move away from the sun in winter, but only tilts away (that’s why it is colder in winter).

Solar/ Lunar Eclipses

Solar eclipses need a new moon while lunar eclipses need a full moon. Depending on where you live in the world you could be covered in the moon’s shadow, the penumbra or umbra. The umbra is the most intense part of the shadow. We can now predict when they will happen.

Moon Phases

During a new moon, the moon is directly in the sun’s path so you cannot see it during the day. There are waxing and waning phases of the moon and each contains a crescent, a gibbous, first quarter (for waxing) and third quarter (for waning). The moon takes 27.3 days to orbit around Earth.

Zenith, etc.

There are three parts when looking into the sky: the meridian (which has to go from north to south), the horizon (which changes depending on where you live) and the zenith (which is directly above you).

Conclusion

For the last bit of class we learned why it seems the planets (example: Mars) appear to go backwards at certain parts in time. It is actually the Earth surpassing Mars that it gives the impression it is moving backwards. We were briefed on the moon phases and we were reminded to hand in notes for the past chapters for next week.