Earth's Rotation and Revolution

Earth's Rotation and Revolution

It is the study of the universe.
Universe - everything that exists.
Astronomer - scientist that studies the universe.
Telescope - magnifies distant objects to be studied.
Refracting telescope - uses lenses to gather light from a distant object.
Reflecting telescope - uses mirrors that focus light onto the lens.

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​Astronomy

The earth spins on its axis - an imaginary line that runs from the North to the South Pole.
One complete spin is called a rotation; this occurs every 24 hours. Rotation is what causes day and night.
Standard time zones - there are 24 time zones of around 15° wide in longitude where it is the same time.
International date line - West of this line, it is 1 calendar day in advance.

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Earth's Rotation

The earth's axis is tilted at 23.5°. As it goes around the sun, the tilt causes parts of the earth to receive more sunlight than other parts. The result is the distinct seasons of the year.
The earth takes 365.24 days to orbit the sun. This is called a revolution.

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Earth's Revolution

The shape of the moon that we see depends on how much of it is lit up by the sun as it orbits the earth.
The different shapes are called the phases of the moon.

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​Phases of the Moon

As the moon orbits the earth, and the earth orbits the sun, sometimes, they can block each other. If the moon blocks the sun perfectly - that is a solar eclipse.
If the earth blocks the light of the sun from hitting the moon - that is a lunar eclipse.

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Eclipses

The corona is the outermost part of the sun's atmosphere. It is usually hidden by the bright light, but it is easily viewable during a total solar eclipse.

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​The Sun's Corona

Tides are the regular rise and fall of the water level along a shore.
Tides are caused by the gravity of the moon, earth and sun.
The water on the side of the earth facing the moon bulges on both sides. This is a high tide.
When the sun, earth, and moon line up, tides can be stronger. (Search: spring tides and neap tides)

Tides