Solar System Objects in the Solar System The

Solar System

Objects in the Solar System The Sun Planets Dwarf Planets Asteroids Comets

Astronomical Unit (AU) The average distance from Earth to the Sun About 150 million km Used to measure distances in our solar system

Motion of Planets Earth’s Rotation One day=24 hours Daytime �Facing the sun Nighttime �Facing away from the sun

Motion of Planets Apparent Motion Sun, moon and stars APPEAR to move in the sky BUT… Earth is rotating west to east

Motion of Planets Revolution Travel once around the sun One year

Motion of Planets Elliptical Orbit Planets travel in an elliptical (oval) orbit

Motion of Planets Seasons Tilted axis + revolution around sun = seasons One year Winter in northern hemisphere is summer in Ear tilt th’s a sa t 2 xis 3. 5 southern hemisphere

Motion of Planets Seasons Equinox �Days with equal amounts of light and darkness Solstice �The longest and shortest day of the year

After seasons experiment: Cause of seasons

After seasons experiment: What if the Earth had no tilt?

After first moon experiment: Synchronous Rotation

After first moon experiment: Same side of the moon

The moon Formation Moon formed 4. 5 billion years ago when a piece of Earth broke off Lunar Cycle Amount of light we can see on Earth from sun’s reflection off the moon

The moon Moon Motion Rotates once on its axis AND revolves around Earth in the same amount of time So…the same side of the moon is always facing Earth Waxing More of moon’s side facing light Waning Less of moon’s side facing light

The moon

The moon 1. 2. 3. 4. 5. 6. 7. 8. New Moon: Moon is not illuminated by sun Waxing Crescent: Moon starts to show more light First Quarter: Half of moon is lit Waxing Gibbous: Most of the moon is lit Full Moon: Entire moon is lit Waning Gibbous: Moon starts to lose some light Last Quarter: Half of the moon is lit Waning Crescent: Small portion is visible

Eclipses Eclipse One object casts a shadow onto another Penumbra Lighter part of a shadow where light is partially blocked Umbra Central, darker part of a shadow where light is totally blocked

Eclipses Solar Eclipse Moon casts a shadow on Earth Lunar Eclipse Earth casts a shadow on the moon

Tides Tidal Force Difference in gravitational force of the moon Tidal Range Difference between water levels at high and low tides

Tides High Tide Higher than average water level Spring Tide Largest daily tidal wave Low Tide Lower than average water level Neap Tide Smallest daily tidal range

The Planets

The Planets

The Planets Centripetal Force • Inward force of gravity that causes an object to move in a circular path

The Planets Gravity • Sun’s gravity holds planets in their orbit • Earths gravity holds moon in its orbit ‘ • Amount of gravity depends on mass and distance

Dwarf Planets Spherical object that orbits the Sun Not the moon of another object Does not have more mass than other objects nearby Made of rock and ice

Asteroids Small rocky objects Orbit the Sun in the asteroid belt between Mars and Jupiter

Comets Made of gas, dust, and ice Moves around Sun in oval shaped orbit

Meteoroids Meteoroid A small rocky particle that moves through space Meteor A streak of light in Earth’s atmosphere made by a glowing meteoroid Meteorite A meteoroid that strikes a planet or a moon Impact crater A round depression formed on the surface of a planet, moon or other space object by the impact of a meteorite

Meteoroids