Earth and beyond - Chapter 13

1. Earth & beyond
WHAT IS OUT THERE?

2. We need to revise:
Solar system
Planets & moons
Orbit/Revolution
Rotation
Day/ night & seasons

3. In many
civilisations,
humans looked
up to the sky and
tried to measure,
record &
understand.

4. Galilei Galileo
Galileo is not only famous for his paintings. He is often
incorrectly credited with the creation of a telescope. (Hans
Lippershey applied for the first patent in 1608, but others may
have beaten him to the actual invention.) Instead, he
significantly improved upon them. In 1609, he first learned of
the existence of the spyglass, which excited him. He began to
experiment with telescope-making, going so far as to grind and
polish his own lenses. His telescope allowed him to see with a
magnification of eight or nine times. In comparison, spyglasses
of the day only provided a magnification of three.
It wasn't long before Galileo turned his telescope to the
heavens. He was the first to see craters on the moon, he
discovered sunspots, and he tracked the phases of Venus.
The rings of Saturn puzzled him, appearing as lobes
and vanishing when they were edge-on — but he saw them,
which was more than can be said of his contemporaries.
Gallileo was one of the scientists who –unlike many at his time-
understood that the Earth rotated around the Sun and not the
other way round.

5. Solar System

6. Solar System
•You see the moon because light from the sun is
reflected into your eyes
•The moon orbits the earth every 27.3 days
•The moon appears to change because it is lit by
the sun and its moving around the earth
Star
The sun
Planets
They orbit the sun:
Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune
Moon
A body that orbits a planet

7. Orbit
 is a path one object takes around another object.

8. Revolution VS Rotation

9. Rotation
 It is a complete spin of Earth on its axis (around its self).
 Each planet spins at a different speed
 Earth takes 24 hours to complete one spin
 This causes Day & Night.

10. What causes Day & Night?
 Each day the sun seems to move
across the sky.
 It is not the sun that is moving… it
is the EARTH!!
 It takes 24 hours for earth to
complete one rotation

11. The angle of sunlight rays
 This torch directed at a
right angle will heat up
the surface much more
than when the torch is at a
smaller angle.
 Note that in the diagram
on the left all the light
reaches a smaller area
than the area illuminated
on the right diagram.

12. Revolution
 Is one complete trip
around the Sun.
 Seasons are caused
by the earth
revolving around the
sun tilted to one
side.