Earth’s relative motion. 1. Kepler’s 1 st law states that planetary orbits are _________________ shapes? 2. Kepler’s 2 nd law states that 2 equal intervals.

Earth’s relative motion

1. Kepler’s 1st law states that planetary orbits are _________________ shapes?

2. Kepler’s 2nd law states that 2 equal intervals of time an imaginary line connecting a planet and the sun will sweep an equal amount of ___________?

3. Kepler’s third law states that the innermost planets orbit ______________________ than the outermost planets.

4. Rotation is the earth spinning on it’s _________________.

5. One trip around the ______________ is called a revolution.

EEn.1.1 Explain the Earth’s role as a body in space. EEn.1.1.1 Explain the Earth’s motion through

space, including precession, nutation, the barycenter, and its path about the galaxy. Explain relative motion of the Earth in the

solar system, the solar system in the galaxy, and the galaxy in the universe—including the expanding nature of the universe; Orbital motion (Earth around the Sun- once/year, seasons depend upon an approximate 23.5 degree tilt); Rotation around our axis (day/night,)

How do galaxies and planets move in the universe?

RotationTurning or spinning of a body on its axis

RevolutionMotion of a body along a path around some

point in space Precession

Slight movement of Earth’s axis 26,000 years

Results in day and night24 hours1,667 km/hr (1,036 mi/hr)

Prove Earth is Rotating? OK!

Earth moves around the sun in an elliptical orbitSpeeds around 107,000 km/hr (66,500

mph)Average distance is 150 million kilometers

Perihelion is the point where earth is closest to the sun

Aphelion is the point where earth is farthest from the sun

Earth’s axis is tilted about 23.5º on its axisThis tilt brings the sun 23.5º south of the

equator on the winter solstace This tilt bring the sun 23.5º north of the

equator on the summer solstace

Earth's Seasons

Direction which earth’s axis points changes very slowly over time without a change in tiltTakes about 26,000 years to complete one

period Currently the axis points toward Polaris

making it the North Star, in 14,000 years Vega will be the North Star.

Precession and polar shift

Earth accompanies the sun as the entire solar system speeds toward a distant star, Vega

The sun revolves around the galaxyOver 230 million yearsAt 250 km/sec

Now Earth is approaching our nearest galactic neighbor, Andromeda

Earth's not orbiting the sun?!

Earth’s only natural satelliteOrbit’s Earth in one monthWhen viewed from the North Pole, the orbit

is counterclockwiseAverage distance is 384,401 kilometersPoint close to the Earth is PerigeePoint farthest from Earth is Apogee

Phases are the amount of moon that appears lit

Half of the moon is always illuminated

Phases result from the motion of the moon and the sunlight reflected from its surface

Every 29.5 days

Moon Phases

supermoon

Daily elevation changes of the ocean surface.

Rhythmic Caused by

gravitational pull of the moon Atmosphere and

ocean are fluids and free to move due to this force.

The sun is further away resulting in less tug

tidal mystery

bay of fundy

The moon pulls on Earth and Earth pulls on the moon

This pull causes the Earth to wobble on its axis by about ½ a degree.Changing in the tilt of the Earth’s axis

How does this differ from precession?

gyroscope demo

Point between 2 or more objects where they balance each otherPoint where 2 celestial bodies orbit each

other

barycenter

barycenter animation

When a moon orbits a planet or a planet orbits a star, both are actually orbiting a point outside the center of the larger body. The moon and earth actually orbit a spot

about 1,710 km below earth’s surface.

Not a true sphere Called an oblate spheroid, geoid, or

ellipsoid

Not equal throughout Poles are squished making a bulge at

the equator Diameter and circumference are greater

at the equator than at the poles.

Earth’s rotation and gravity Gravity pulls on the mass causing it to

contract Rotation causes earth to flatten due to

centrifugal forceThe force that causes objects to move

outward, away from the center of gravity We call this the coriolis effect

coriolis effect

Topography- study of surface shape and feature

On a global scale this difference is very small

Mt. Everest is about 8,850 m above sea level

The Mariana Trench is about 10,900 m below sea level

The difference is only about 19,000 m or 12 mi