Astronomy

Chapter 1: Earth in Space

Astronomy

Study of moon, stars, and objects in spaceNot “astrology”

The Big Bang Theory

the universe was created between 10 billion and 20 billion years ago

explosion that hurled matter and in all directions.

1927, Georges Lemaître and Edwin Hubble

1964 by Arno Penzias and Robert Wilson

Movements of the Earth

Rotation is equal to 24 hours Axis – imaginary line that passes

through the earth’s center. Points to the North Star.

Rotation – Earth’s spinning on its axis in an eastward direction.

creates day and night

Movements of Earth

2. Revolution

Movement of Earth around the sun.Creates a year of time.Ellipse – shape of the orbit The earth is not

always the same distance from the sun.

What causes the seasons?

The tilt of the Earth, not the rotation around the sun.Axis is tilted 23.5 degrees

Summer Solstice

June 21 or 22Longest day length in Northern HemisphereShortest day length in Southern Hemisphere.

Fall Equinox

September 22 or 23Equal hours of day and nightSuns rays directly at the equator

Winter Solstice

December 21 or 22Northern Hemesphere – shortest day light hoursSouthern Hemesphere – longest day length

Spring Equinox (Vernal)

March 21 or 22Equal day and night hours

Section 2: Phases, Eclipses, Tides

Earth – Moon System Average Earth- Moon distance =

240,000 miles Average distance of sun-Earth =

93,000,000 miles Earth’s Diameter = 8,000 miles Moon’s Diameter = 2,000 miles

Earth is 4x the size of the moon

If 1” = 2,000 miles

Earth will be 10 feet away from the moonEarth-Moon system will be ¾ mile away from the sun.

Physical Properties of Moon

Weak gravityNo atmosphereHighlands – light areas, light rockMaria – dark patches, smooth, dark lavaCraters – 4 billion years old

Giant Impact Hypothesis

Mars sized body hit the Earth about 4 billion years agoFragments from the collision joined to form the moonSurface covered by hot molten rock

                                                           

                

Movements of the moon

Moon rise and sets 50 minutes later each nightRotation: 27.3 daysRevolution around the Earth – 27.3 daysRotation on Earth’s

Phases of the moon – Caused by the position of the Earth, moon, and sun

Animation of phases

2 Main phases of the moon

Waning – Moon getting smaller, less lit up

Waxing – Moon appears to get larger, more lit up

Eclipses:

Solar Eclipse: When moon’s shadow hits Earth

Umbra: total

Penumbra - partial

Lunar Eclipse:

Earth’s shadow hits the moon

Tides:

Occur due to differences in how much the moon pulls on different parts of Earth.

Spring Tide

Takes place during new or full moon – Gravity of sun/moon pull in the dame directionCauses a greater difference between High and Low tide

Neap Tide

Least difference between High and Low tide

Intertidal Zone

Under water at high tide and dry during low tide.

Rockets and Satellites

Artificial Satellites: any artificial object that orbits around the Earth: Comminications,

navigation, collecting weather information, data, research, relay TV signals.

Satellite : ex. Space Stations

1973 – skylab1986 – MirToday – international space station

Space Shuttles

1970’sreusable