Transcript Space (Part 1)

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Introducing the Solar System
The Solar System is made up
of various celestial objects:
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the Sun
the planets
moons
asteroids
comets.
How do these objects interact?
The Sun is a star – a massive ball of hot glowing gas.
It has the strongest gravitational field in the Solar System.
All the other celestial bodies orbit around it.
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The rotation of the Earth
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What time is it?
It is 4 am in London.
Casablanca
What is the time in
the rest of the world?
place
GMT
time
Casablanca
+1 hr
5 am
Pretoria
+2 hr
6 am
Antananarivo +3 hr
7 am
Philippines
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+8 hr 12 pm
Pretoria
Philippines
Antananarivo
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The path of the sun in the sky
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What are hemispheres?
The Earth is divided into two hemispheres, separated by
the equator.
northern
hemisphere
equator
southern
hemisphere
Why do the hemispheres have different seasons at
different times of the year?
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The seasons
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What is the season?
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The Moon
The Sun and the Moon look about the same size from
Earth, but they are not.
The Sun is about 400 times wider than the Moon but is
400 times further away!
sunlight
The Moon takes just over 27 days to orbit the Earth.
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The phases of the Moon
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Phases of the Moon activity
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Questions about the Moon
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Eclipses
A solar eclipse happens when
the Moon passes between the
Sun and the Earth, casting a
shadow over the Earth.
The last solar eclipse over the
UK was on 11th August 1999.
They are rare in the UK.
A lunar eclipse happens when
the Earth passes between the
Sun and the Moon, casting a
shadow over the Moon.
Lunar eclipses happen in
most years.
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What happens during a solar eclipse?
Where must the Moon be for a solar eclipse to take place?
During a solar eclipse the Moon moves directly between
the Sun and the Earth, blocking the Sun’s rays from
reaching part of the Earth.
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What happens during a lunar eclipse?
Where must the Moon be for a lunar eclipse to take place?
During a lunar eclipse the Moon is on the opposite side
of the Earth to the Sun, blocking the Sun’s light from
reaching the Moon.
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Questions about eclipses
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Gravity and satellites
A satellite is any object that orbits another object.
The Moon is a natural satellite of the Earth and is kept in
orbit by the attraction of the Earth’s gravity and by its motion.
An artificial satellite is
an object made by, and
put into orbit by, humans.
Why do you think satellites
stay in orbit, instead of
falling back onto the
surface of the Earth or
drifting off into space?
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Newton’s thought experiment
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Orbit height and speed
Imagine the mountain in Newton’s
thought experiment was lower.
If the same amount of gunpowder
was used, would a ball shot from
the lower mountain travel the
same distance as from the high
mountain?
No. More gunpowder would be needed
to make the ball travel the same distance. Therefore, more
gunpowder would be needed to make the ball go into orbit.
This means that if a satellite orbits the Earth at a lower
altitude, it needs to travel faster to stay in orbit.
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Satellite orbits
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Which type of satellite?
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What is the Hubble Space Telescope?
The Hubble Space Telescope (HST) is a satellite in orbit
around the Earth. It was deployed from the Space Shuttle
Discovery on 24 April 1990.
The HST is outside the
Earth’s atmosphere and
does not experience the
same interference as
Earth-based telescopes.
This means that its
images of the Universe
are much more detailed
than images observed
from Earth.
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Questions about satellites
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Labelling the planets
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Relative size of the Universe
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Is Pluto a planet?
In 2006, the International
Astronomical Union
defined a planet as:
“a celestial object that
orbits the Sun, has enough
mass to be spherical, and
has cleared the area
around its orbit of objects.”
This photograph shows Pluto and its moon, Charon. Pluto’s
orbit is surrounded by smaller objects which have not been
cleared by its gravitational field.
Pluto and the other ‘smaller’ planet-like objects such as Eris
and Ceres have now been reclassified as ‘Dwarf Planets’.
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Data on the Solar System
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The history of the Solar System
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Ideas about the Solar System
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