Transcript Gravity and our Solar System

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Gravity and Space
Gravity
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Gravity is an attractive force that affects anything with mass:
Note that this
force goes both
ways – the Earth
is attracted to us.
Gravity
Gravity depends on 2 things:
1) The mass of
the objects
F
If you double the
mass of one object
you double the force
F
2) The distance between them
F
If you double the
distance the gravitational
force decreases
F
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Gravity and our Solar
System
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• 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
Gravity and our Solar
System
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• 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!
Now let’s learn about…
An overview of the
Solar System
The 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.
Mercury
• 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.
Venus
• 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.
Earth
• 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.
Moon
Mars
• 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 Mars
Phobos
Deimos
Jupiter
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

The Great Red Spot,
a huge storm of
swirling gas that has
lasted for hundreds of
years.
Jupiter does not have
a solid surface. The
planet is a ball of
liquid surrounded by
gas.
Jupiter has over 65
moons!
Io
Europa
Ganymede
Callisto
Saturn
• 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 Saturn
• Saturn’s rings are not
solid; they are
composed of small
particles of ice and
rock.
Uranus
• 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.
Neptune
• 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 This?
Now, let’s look at a few of history’s greatest
contributions to space exploration and learn about
the different crafts used.
Galileo Galilei
He was a famous mathematician and astronomer who made
great advances in the telescope – the first step in
exploring space.
Robert 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?
Rockets are space craft with chemical propellants
used to escape the earths gravity.
Sputnik 1
The first manmade satellite to orbit the earth –
Soviet Union.
Explorer 1
The first U.S. satellite to orbit the Earth.
What is a satellite?
An object that orbits another object. They
can be natural , like a moon orbiting a planet,
or artificial, like Explorer 1.
Natural Satellites
Mercury
Venus
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These planets are all
satellites of the sun
Earth
Mars
Jupiter
Saturn
Uranus
Neptune
Pluto
Artificial Satellites
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Artificial satellites have been around for 50 years
and have 3 main uses:
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
Voyager 1 and 2
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These were probes discovered many things
including the rings and moons of the far away gas
giant. It is the farthest man mad object in
space.
What is a probe?
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A space probe is a robotic spacecraft that leaves Earth orbit
and explores space.
NASA
Strands for National Aeronautics and Space
Administration. It is our governmental agency
devoted to exploring space.
Apollo Missions
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These missions were to land a man on the moon and return
him safely.
"That's one small step for a
man. One giant leap for
mankind."
- Neil Armstrong
The Space Shuttle
This program created the first reusable space craft that
could carry people and cargo to and from space.