motion in the universe
DESCRIPTION
Motion in the Universe. Earth’s relative motion. Daily Review. Kepler’s 1 st law states that planetary orbits are _________________ shapes? Kepler’s 2 nd law states that 2 equal intervals of time an imaginary line connecting a planet and the sun will sweep an equal amount of ___________? - PowerPoint PPT PresentationTRANSCRIPT
MOTION IN THE UNIVERSE
Earth’s relative motion
DAILY REVIEW1. 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.
ESSENTIAL STANDARD 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,)
ESSENTIAL QUESTION How do galaxies and planets move in
the universe?
MOTIONS OF EARTH Rotation
Turning or spinning of a body on its axis Revolution
Motion of a body along a path around some point in space
PrecessionSlight movement of Earth’s axis
26,000 years
ROTATION Results in day and night
24 hours1,667 km/hr (1,036 mi/hr)
Prove Earth is Rotating? OK!
REVOLUTION 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 AND SEASONS 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
PRECESSION 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-SUN MOTION 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?!
MOTIONS OF THE EARTH-MOON SYSTEM Earth’s only natural satellite
Orbit’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 OF THE MOON 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
TIDES (PG 458) 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 mysterybay of fundy
NUTATION 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
BARYCENTER Point between 2 or more objects where
they balance each otherPoint where 2 celestial bodies orbit each
other
barycenter
barycenter animation
MORE BARYCENTER 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.
MAKE A FLYING GYROSCOPE! A gyroscope rotates allowing you to see precession,
rotation, and nutation Flying gyroscopes are able to fly extremely long
distances You are going to make a flying gyroscope out of
paper! We will launch these gyroscopes outside (weather
permitting or a hallway if not) to see who can get their to fly the farthest
As your gyroscope flies, imagine an axis running through the center of it, and try to see the rotation, precession, and nutation. You will describe it
make a flying gyroscope
EARTH’S SHAPE
EARTH’S SHAPE Not a true sphere Called an oblate spheroid, geoid, or
ellipsoid
CIRCUMFERENCE AND DIAMETER Not equal throughout Poles are squished making a bulge at
the equator Diameter and circumference are greater
at the equator than at the poles.
WHY? 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
LOCAL TOPOGRAPHY 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
REMEMBER You have a test on Thursday. We will review tomorrow.