PowerPoint Presentation

Chapter 1"Earth, Moon, and Sun"

AstronomyThe study of the moon, stars, and other objects in space.

Axis:An imaginary line that passes through Earths center at the North and South polesEarths axis is tilted at an angle of 23.5 degrees from verticalThis tilt of Earths axis is what causes the Seasons

Earth in SpaceStand in place, and make one complete turn.You have just rotated. Take a trip around your desk.You have just revolved.What does it look like when you rotate and revolve at the same time?

THREE "R's" OF ASTRONOMYROTATION - MOTION WHERE AN OBJECT TURNS ON AN IMAGINARY AXIS. This causes

REVOLUTION - PLANETARY MOTION WHERE AN OBJECT MOVES AROUND THE SUN. This causesDay and NightA yearRETROGRADE - PLANETARY MOTION WHERE THE PLANET MOVES EAST TO WESTOPPOSITE FROM THE NORM.5Earth in Space

Earth rotates eastward, and a point on the equator rotates at about 1600 kilometers in an hour!Earth in Space

Earths path around the sun is called an orbit.Notice, our orbit is not a perfect circle! It is called an .EllipseEarth in Space

Earth

causingcausingrevolvesrotates

YearsDay and night

On its axisAround the sun

Understanding the seasonsLatitude:The measurement of distance from the equator, expressed in degrees north and south.Solstice:One of the two days each year, when the noon sun is overhead at 23.5 degrees north or south latitude.In the Northern hemisphere, the noon sun is at 23.5 degrees south during the Winter solsticeThe date for this would be(what is the shortest day of the year?)Around Dec. 21st

Equinox:Halfway between the solstices, neither hemisphere is tilted toward or away from the sun. This only occurs twice a year, and during this time the noon sun is directly overhead at the equator.Vernal equinox:spring equinox occurs around March 21st, and marks the start of spring in the Northern Hemisphere.Autumnal equinox:Occurs around September 23, and marks the start of fallDay and night would be aboutequalHow do seasonal changes affect living things?

Earth in Space

Earth in Space

The MoonThe moon is about 384,400 kilometers from Earth. The positions of the moon, Earth, and the sun cause the phases of the moon, eclipses, and tides.It takes the moon about 27.3 days to revolve around the Earth in a non-circular orbit.The moon rotates on its axis every 27.3 days. Its day and year are equal, so we only ever see one side of the moon.Phases: the different shapes of the moon you see from Earth.

The MoonNew Moon

The moon produces no light of its own. It only reflects sunlight.

The MoonNew Moon Waxing Crescent

The phase of the moon you see depends on how much of the sunlit side of the moon faces Earth.

The MoonNew Moon Waxing Crescent First Quarter

The MoonNew Moon Waxing Crescent First QuarterWaxing Gibbous

The MoonNew Moon Waxing Crescent First QuarterWaxing GibbousFull Moon

The MoonNew Moon Waxing Crescent First QuarterWaxing GibbousFull Moon Waning Gibbous

The MoonNew Moon Waxing Crescent First QuarterWaxing GibbousFull Moon Waning GibbousThird Quarter

The Moon

New Moon Waxing Crescent First QuarterWaxing GibbousFull Moon Waning GibbousThird Quarter Waning Crescent

Eclipse:Occurs when the moons shadow hits Earth, or Earths shadow hits the moon.Solar eclipse:Occurs when the moon passes between Earth and the sun, blocking the sunlight from reaching Earth.Umbra:The darkest part of the moons shadow (its cone shaped. Light from the sun is completely blocked by the moon.Penumbra:The shadow cast by the moon that is not as dark as the umbra. Part of the sun is visible from Earth. People in this area, only see a partial eclipse.Solar Eclipse

Corona The outer layer of the suns atmosphere It is only visible during an eclipse.

Occurs at a full moon when Earth is directly between the moon and sun.Lunar eclipse:

Unlike a solar eclipse, a lunar eclipse can be seen anywhere on Earth that the moon is visible.A lunar eclipse can be partial or total. It all depends on the alignment of the Earth, moon, and sun.

EclipsesTides:The rise and fall of water (oceans), every 12.5 hours or so. The water rises for 6 hours, then falls for 6 hours. Tides occur mainly because of differences in how much the moon pulls on different parts of Earth.Gravity:The force that pulls two objects (Earth and moon) toward one another.Mass versus Weight:Mass is the amount of matter in an object, while weight is a measure of the force of gravity on an object.Spring tide:A tide that has the greatest difference between high and low tide. Occurs during new moon, when gravity of the sun and moon pull in the same direction.Neap tide:Occurs twice a month (during 1st and last quarter). The sun & Earth & moon are at a right angle.