Transcript 2.13 Understanding our Universe

9 April, 2016
2.13 Understanding our Universe
What is
this
image?
Key terms
• Orbit: the path of an object moving through
space such as the path of the Earth as it
goes around the sun
The Solar System
• The Solar System consists of the Sun
and all the objects that are attracted to the
Sun by gravity
• These include the eight planets and other
objects such as asteroids and meteroids
• The Sun is the brightest star and is the
centre of the Solar System
• Because the Sun is so huge, its gravity
holds the planets in their orbits around it
Objects in the night sky (1)
• If you look at a clear night sky, you will see that it is filled
with various objects
• With the naked eye you can see the light of thousands of
stars, which seem to be arranged in patterns, called
constellations
• Because the Earth rotates, the stars rise and set like the
Sun
• You will also see planets
• These do not shine their own light but reflect light from
other sources
• Because they are close to the Earth, they shine brightly
and do not twinkle
Objects in the night sky (2)
• If you are lucky you may see an object with a bright tail
• This is likely to be a comet, which are made from rock, dry ice and
frozen gases such as CO2 and CH4.They come from outside our
Solar System
• You may also see ‘shooting stars’ which are meteors, these are bits
of dust and rock which enter the Earth’s atmosphere
• Astronomers have also discovered hundreds of stony objects called
asteroids, which also orbit the Sun
• The Earth’s moon is clearly visible and its appearance changes
through the month as it orbits the Earth
• With a good telescope you can see that other planets have moons.
Jupiter has 63 moons, one of which has volcanoes.
Origin of the Solar System
• Astronomers believe that the Solar System was formed
when clouds of gas and dust collided
• Eventually our sun was formed, together with other
objects such as planets
• Asteroids and meteoroids are believed to be remains of
that cloud.
• Geologists have investigated meteorites and estimate
they are 4.5 billion years old
• The effect of meteoroids and asteroids that hit the
surface of the moon can clearly be seen even with the
naked eye
• Some astrophysicists believe that the Earth was formed
by collisions of asteroids and meteoroids
Assessment Activity
• You are an astronomer working for an
observatory. You are invited to a primary
school to describe our Solar System to
young children
– Working in groups of three, construct a model
of the solar system, showing the distances of
the eight planets from the Sun
– In your groups, investigate the theory
described above of how the Solar System
was formed. Present your results in the form
of a poster