Effects of Gravity on Planetary Orbits The Suns

Effects of Gravity on Planetary Orbits · The Sun’s gravitational attraction, along with the planet’s inertia, keeps the planets moving in elliptical orbits and determines how fast they orbit.

Gravity TAB Gravity is affected by mass Mass= amount of matter in an object Inertia is affected by mass Inertia is an objects desire to continue doing what it is doing. EX. An object in motion will stay in motion unless a force is acted upon it EX. An object at rest will stay at rest until a force is acted upon it

• Planets nearer the Sun orbit faster than planets farther from the Sun because the gravitational attraction is greater. • When a planet is farther from the Sun, the gravitational attraction between them decreases and the planet orbits slower.

Space Trash Tab: Comets are small objects with a main body or head made of dust and ices of water, methane, and ammonia.

Comets have a tail that only emerges as the comet gets closer to the Sun during its orbit. The tail always points away from the Sun. Comets have unique long, narrow elliptical orbit. http: //www. windows. ucar. edu/tour/link=/comets/comet_model_interactive. html

Space Trash Tab: Meteoroids • Meteoroids are chunks of rock that move about within the solar system. • Location and movement result in the different terms: ¬Meteor – when the chunk of rock burns up in a planet’s atmosphere; or ¬Meteorite – when the chunk of rock strikes the surface of a planet or moon.

Meteoroid

Meteorite

Most meteoroids are no bigger than a pebble. Large meteoroids are believed to come from the asteroid belt. Medium sized meteoroids may have come from the Moon or Mars. If a meteoroid falls into the Earth's atmosphere, it will begin to heat up and start to glow. This is called a meteor. Most of the original object burns up before it strikes the surface of the Earth (falling stars). Any leftover part that does strike the Earth is called a meteorite.

A meteorite can make a hole, or crater, in the ground when it hits.

What causes the seasons? 1. The tilt of the Earth on its axis 2. The length of the day 3. The angle of the Sun’s rays NOT the distance between Earth and the Sun Earth Sun

How many times does the Earth rotate on its axis in a year? 365. 25 Sun Earth

As seen from the North Pole, which direction does the Earth rotate? Counter-clockwise Sun Earth

Sun What causes the phases of the Moon? The amount of reflected light visible from Earth Moon

What causes an eclipse? Sun Solar Eclipse · A solar eclipse occurs when the Moon is directly in-between the Sun and Earth, blocking the Sun's light casting a shadow over a certain area on Earth.

Lunar Eclipse Sun · A lunar eclipse occurs when Earth is directly inbetween the Sun and the Moon, blocking the Sun's light so that Earth's shadow hits the Moon casting a shadow over the Moon. Earth

The Moon and Earth’s Tides

Craters on the Moon

Maria

Highlands

MOON PHASES

• “What do I know about tides? ” • Read Marching to the Beat of Tides on p. 253 • Describe how tides affect fiddler crabs, oysters and scallops, rock barnacles, and razor clams. •

Effects of Gravity on Tides The Moon being closer to Earth than the Sun has the greatest pulling effect on tides, the rise and fall of ocean water.

The Sun also pulls on Earth and can combine its force with the Moon causing even higher tides called spring tides.

The Sun can be a right angles, pulling against the Moon’s pull, causing very little tidal change, neap tides. There is about a 7 day interval between springs and neaps.

• Read Can Water Fall Up? On p. 255 and answer questions at the end. • Inquiry 16. 1: Review tidal data on p. 246250 and complete procedures 1 and 2. •