H. 8) Solar System Motion (Student Copy)

SOLAR SYSTEM

MOTION

AT THE CENTRE

 _{For more than 2000 years, starting with the Ancient Greek} philosophers, human beings thought that Earth was the centre of the Universe and everything, including the Sun and other planets, rotated around us.

 _{_________________________ – model of the Universe in which}

Earth was the centre.

 _{It didn’t explain everything that happened in the sky} though.

 _{Some planets, like Mars, seemed to go in one direction,} stop, then move in the opposite direction.

 _{If all the planets circled the Earth, that would be} impossible!

NEW MODEL



_{In the 16}

century, Nicolaus Copernicus came up

with the

_________________________

, which predicted

that the

_________

was the centre of the Universe

and everything else around it.



_{It did a better job of explaining the motion of the}

planets.



_{Galileo used his telescope to verify that Copernicus}

was right.



_{By seeing that Venus had different phases, like our}

Moon, he concluded that the Sun was the centre of

the Universe.

GEOCENTRIC VS.

HELIOCENTRIC

MORE CELESTIAL

OBJECTS

 _{There are millions of smaller objects in our Solar System}

 _{______________ were previously talked about as small, irregular shaped}

celestial objects made of mostly rock and metal. They are typically ___ m to more than ____ km in diameter. Most of them are located between Mars and Jupiter in the _______________________.

 _{_____________ are a piece of rock or metal that are smaller than asteroids.}

 _{When a meteoroid enters Earth’s atmosphere, it starts to burn up in a}

bright streak of light across the sky, called a _____________. You would

typically call this a “shooting star”. When a meteor reaches the ground, it is called a _________________.

 _{_________ are a large chunk of ice, rock, and dust that orbit the Sun. They}

are from __ km to ___ km in diameter. When a comet gets close enough to the Sun, the frozen gases are evaporated by the Solar wind from the Sun. When this happens, you can see a glowing head and tail from Earth.

PLANETARY MOTION

_{Two types of Planetary Motion:}

 _{_________________}  _{______________}



_{The planets}

_{________________}

_{(orbit a central point or}

object) around the Sun in an oval or elliptical shape.



_{Earth takes 365 days or 1 Earth year to go around the Sun.}

_{The farther the planet is, the longer it takes to orbit the}

Sun because the distance it has to go is much larger and

the force of gravity acting on it is much weaker from the

Sun.

HOW LONG?

PLANET

TIME AROUND THE SUN

(EARTH DAYS)

Mercury

88

Venus

225

Earth

365

Mars

687

Jupiter

4380 (12 years)

Saturn

10 950 (30 years)

Uranus

30 660 (85 years)

PLANET ROTATION



_{You have probably noticed that the Sun rises in the East and sets}

in the West.



_{This is because Earth}

_{____________}

_{(moves, or turns around a}

centre point) on it’s

_________

(an imaginary line around which an

object rotates)



_{The axis goes from the}

_{_________________}

_{to the}

_{_________________}

_.

_{Earth and almost all the other planets rotate}

_{_______}

_to

_{_______}

_.

_________

is unique because it rotates in the opposite direction

from the rest of the planets.



_{As Earth rotates, the portion of the Earth that faces the Sun}

experiences

_____

. The portion of the Sun that doesn’t face the

sun experiences

___________

.



_{The amount of time it takes a planet to rotate on its axis tells us}

how long the days will last.



_{It takes Earth}

_{___}

_{hours to complete one rotation (360°), which}

HOW LONG?

PLANET

TIME IN ONE DAY

(EARTH HOURS)

Mercury

1416 (59 days)

Venus

5832 (243 days)

Earth

24

Mars

24.6 (1.026 days)

Jupiter

9.84

Saturn

10.2

Uranus

17.9

STAND UP



_{You are the Earth.}

_{Rotate slowly from}

left to right (west to

east) and tell me

which way the Sun on

the screen looks like

it is moving.



_{Next, as you rotate,}

once you can’t see

the Sun, that is when

you would experience

night time on Earth.

TIME ZONES

 _{Since the Earth is rotating and the Sun does not hit all parts of} the Earth at the same time, different hours of the day happen at different times around the world.

 _{Ex. When it is 5pm in Milton, it is 2pm in Los Angeles.}

 _{This is because the Earth is rotating from West to East, which} means we see the Sun before they do in California.

 _{To make sure we all use the same 24 hour clock, people created} areas on Earth that revolve around when these areas experience

___________ __________ (12:00pm) or when the Sun is directly above our heads.

 _{_________________ – a vertical section of Earth’s surface that has a}

uniform time.

CANADA’S TIME

ZONES

EARTH’S TILT

 _{Remember the theory of the Moon hitting the Earth and} knocking it off it’s original axis?

 _{The Earth currently sits tilted at ____ from the vertical axis} when you compare it to the Sun.

 _{This causes the Northern Hemisphere (above the equator)} and Southern Hemisphere (below the equator) to tilt away from the Sun every 6 months.

 _{When the hemispheres are tilted towards the Sun, it} experiences more hours of sunlight each day.

 _{This means that the amount of sunlight at the poles on} Earth is more extreme from sun all day to none at all depending on the time of year.

EARTH’S TILT & THE

SUN

SEASONS

 _{When the Northern hemisphere is tilted towards the Sun, a lot of}

sunlight spreads over a small part of Earth’s surface.

 _{This causes a temperature increase, which is when we experience} _____________.

 _{When the Northern hemisphere is tilted away from the Sun, sunlight}

spreads over a bigger area

 _{This causes the temperature to drop, which is when we experience} ____________.

 _{When it is Winter in the Northern Hemisphere, it is Summer in the}

Southern Hemisphere.

 _{At the Equator the amount of Sun’s rays changes very little, so they}

don’t have 4 seasons like us. Instead, they have a ________ and ______

WHEN WE HAVE

WINTER…

SOLSTICES &

EQUINOXES

 _{__________ – a day when Earth’s axis is most inclined toward,}

or away from, the Sun.

 _{In the Northern hemisphere, around June 21}st is the

___________ ___________ (longest day of the year for us) and around December 21st is the _________________ (shortest day of the year for us)

 _{______________ – days when the hours of daylight equal the}

hours of darkness.

 _{In the Northern hemisphere, between the solstices, we have}

two days where the day time equals the night time.

 _{Around March 21}st is called the _________________ and around September 21st is called the ____________________.

SOLSTICES &

EQUINOXES

SEASONS ON OTHER

PLANETS

 _{Other planets also experience seasons in our Solar System as long as}

they have a tilted axis like Earth does.

 _{Mars, Saturn, and Neptune are much further from the Sun than Earth is}

which means it takes longer for them to complete one revolution around the Sun.

 _{Their seasons are much longer and, in general, much colder than ours.}  _{Uranus has an axis that is tilted so much it is almost on its side.}

 _{The poles of Uranus face the Sun for long periods of time, making the}

seasons very extreme.

 _{The planets that do not have a tilt, which means they have no seasons,}

are _____________, ___________, and _______________.

 _{No tilt means that the planet gets the same amount of Sun at all times in}