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Gravity and SpaceGravity and Space

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GravityGravityGravity is an attractive force that affects anything with mass:

Note that this force goes both ways – the Earth

is attracted to us.

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GravityGravityGravity depends on 2 things:

If you double the distance the

gravitational force decreases

F

F

1) The mass of the objects

2) The distance between them

F F

If you double the mass of one object

you double the force

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Gravity and our Solar Gravity and our Solar SystemSystem

• The Sun’s gravity is what holds our solar system together.

• Since Jupiter is the largest planet, it has the most gravity.

• Pluto has the least amount of gravity of all the planets

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Gravity and our Solar Gravity and our Solar SystemSystem

• What do you think would happen to the planets if the sun’s gravitational pull suddenly disappeared?

To get an explanation WATCH THIS!

• GRAVITY – it’s what holds our Solar System together!

An overview of the

Solar System

Now let’s learn about…Now let’s learn about…

The SunThe Sun

• The sun is the biggest, brightest, and hottest object in the solar system.

• The sun is an ordinary star.

• The sun is made of about 70% hydrogen and 28% helium.

MercuryMercury

• Mercury is solid, rocky, and is covered with craters.

• Mercury has almost no atmosphere.

• There are no moons on mercury

• Mercury is the smallest of our eight.

VenusVenus

• Venus is the sixth largest planet. It’s slightly smaller than Earth.

• The surface is rocky and very hot. The atmosphere completely hides the surface and traps the heat.

• Venus has no moons.

EarthEarth

• Earth is the fifth largest planet and the third from the sun.

• It is a rocky planet covered mostly by water.• The Earth has one moon.

MoonMoon

MarsMars

• Mars is the fourth planet from the sun.

• Mars is rocky • Mars has a thin

atmosphere of mostly carbon dioxide.

• Mars has two small moons.

Moons of MarsMoons of Mars

Phobos

Deimos

JupiterJupiter

The Great Red Spot, The Great Red Spot, a huge storm of a huge storm of swirling gas that has swirling gas that has lasted for hundreds of lasted for hundreds of years.years.

Jupiter does not have Jupiter does not have a solid surface. The a solid surface. The planet is a ball of planet is a ball of liquid surrounded by liquid surrounded by gas.gas.

Jupiter has over 65 Jupiter has over 65 moons!moons!

IoIo

EuropaEuropa

GanymedeGanymede

CallistoCallisto

SaturnSaturn• Saturn is the second largest planet and the sixth

from the sun.• Saturn is made of materials that are lighter than

water. If you could fit Saturn in a lake, it would float!• Saturn has 62 moons.

Rings of SaturnRings of Saturn

• Saturn’s rings are not solid; they are composed of small particles of ice and rock.

UranusUranus

• Uranus is the third largest planet and the seventh from the sun.

• Uranus is one of the giant gas planets.

• Uranus is blue-green because of the methane in its atmosphere.

NeptuneNeptune

• Neptune is the fourth largest planet and the eight from the sun.

• Like Uranus, the methane gas gives Neptune its color.

• Neptune has 13 known moons

How Did We Learn All How Did We Learn All This?This?

Now, let’s look at a few of history’s greatest Now, let’s look at a few of history’s greatest contributions to space exploration and learn contributions to space exploration and learn

about the different crafts used.about the different crafts used.

Galileo Galilei Galileo Galilei

He was a famous mathematician and astronomer who made great advances in the telescope – the first step in exploring space.

Robert GoddardRobert Goddard

Robert H. Goddard is know as the American father of modern rocketry He built and tested the world's first liquid-fuel rocket in 1926. Over the course of his career, Goddard not only developed the calculations for rocket flight and also made advances in rocket design and construction.

What is a rocket?What is a rocket?

Rockets are space craft with chemical Rockets are space craft with chemical propellants used to escape the earths propellants used to escape the earths

gravity.gravity.

Sputnik 1Sputnik 1The first manmade satellite to orbit the earth The first manmade satellite to orbit the earth

– Soviet Union.– Soviet Union.

Explorer 1Explorer 1The first U.S. satellite to orbit the Earth.The first U.S. satellite to orbit the Earth.

What is a satellite?What is a satellite?

An object that orbits another object. An object that orbits another object. They can be natural , like a moon They can be natural , like a moon orbiting a planet, or artificial, like orbiting a planet, or artificial, like

Explorer 1. Explorer 1.

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Natural SatellitesNatural Satellites

Mercury

MarsJupiter

Saturn

Neptune

Uranus

Pluto

VenusEarth

These planets are all satellites of the sun

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Artificial SatellitesArtificial Satellites

1) Observation (e.g. Hubble Space Telescope) – these are in orbit high above the Earth and can observe the universe without interference

2) Communications – radio, phone, navigation

3) Monitoring – weather and spying

Artificial satellites have been around for 50 years and have 3 main uses:

Voyager 1 and 2Voyager 1 and 2

These were probes discovered many things These were probes discovered many things including the rings and moons of the far including the rings and moons of the far

away gas giant. It is the farthest man mad away gas giant. It is the farthest man mad object in space.object in space.

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What is a probe?What is a probe?

A space probe is a robotic spacecraft that leaves Earth orbit and explores space.

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NASANASAStrands for National Aeronautics and Space Strands for National Aeronautics and Space

Administration. It is our governmental Administration. It is our governmental agency devoted to exploring space.agency devoted to exploring space.

Apollo MissionsApollo MissionsThese missions were to land a man on the moon These missions were to land a man on the moon

and return him safely. and return him safely.

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"That's one small step for a man. One giant leap for mankind."- Neil Armstrong

The Space ShuttleThe Space Shuttle

This program created the first reusable space craft This program created the first reusable space craft that could carry people and cargo to and from that could carry people and cargo to and from

space.space.