Motion in the Universe

Earth’s relative motion

1. 2.

3.

4. 5.

Kepler’s 1st law states that planetary orbits are _________________ shapes? 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 ___________? Kepler’s third law states that the innermost planets orbit ______________________ than the outermost planets. Rotation is the earth spinning on it’s _________________. 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?

 Rotation 

Turning or spinning of a body on its axis

 Revolution 

Motion of a body along a path around some point in space

 Precession 

Slight movement of Earth’s axis 

26,000 years

Prove Earth is Rotating? OK!

 Results  

in day and night

24 hours 1,667 km/hr (1,036 mi/hr)

 Earth

moves around the sun in an elliptical

orbit  

Speeds 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 Seasons

 Earth’s  

axis is tilted about 23.5º on its axis

This 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

Precession and polar shift

 Direction

which earth’s axis points changes very slowly over time without a change in tilt 

Takes 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.

Earth's not orbiting the sun?!

 Earth

accompanies the sun as the entire solar system speeds toward a distant star, Vega  The sun revolves around the galaxy  

Over 230 million years At 250 km/sec

 Now

Earth is approaching our nearest galactic neighbor, Andromeda

 Earth’s     

only natural satellite

Orbit’s Earth in one month When viewed from the North Pole, the orbit is counterclockwise Average distance is 384,401 kilometers Point close to the Earth is Perigee Point farthest from Earth is Apogee

Moon Phases supermoon

 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

tidal mystery bay of fundy

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

gyroscope demo

 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?

barycenter animation barycenter

 Point

between 2 or more objects where they balance each other 

Point where 2 celestial bodies orbit each other

 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 force 

The 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 