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Astronomy:
From planets to the Universe
Lets start with our Solar System
Our solar system
• The sun is a very ordinary star among
thousands of millions of other stars in
the Milky Way galaxy.
• It has a planetary system made up of
planets, dwarf planets, moons,
asteroids, comets and other material left
over after its formation.
Planets in our solar system:
• Mercury
• Venus
• Earth
• Mars
• Jupiter
• Saturn
• Uranus
• Neptune
Solar system
• What do you think is incorrect
about this representation of the
solar system?
• They are misleading as they do not
show the relative sizes of our sun and
the planets or the vast distances
between them.
Task : Constructing a model.
• To appreciate the relative size of the
sun and the planets we shall make a
model.
• Using the items suggested on the chart,
arrange them in the correct order and
make labels for them.
Body
Diameter Distance to scale Distance to Suggested
from one object scale of
object
to next / m
object to sun
/m
Sun
240
10
-
Basketball
Mercury
0.8
9
10
Pinhead
Venus
2
7
19
Peppercorn
Earth
2.1
13
26
Peppercorn
Mars
Jupiter
1.1
24
95
112
39
134
Pinhead
Grape
Saturn
20
249
246
Marble
Uranus
8
281
493
Dried pea
Neptune
7.8
244
774
Dried pea
• Now that we have represented the solar
system, we must try and understand the scale
.
• Calculate the approximate scale if:
• If the earth is 12,724 km wide and in this
model it is 2.1 mm
• The sun is 1,391,900 km in diameter whereas
the basketball is only 240 mm in diameter.
• The scale is approximately 1: 6,000,000.
• This means that 1 m will represent about
6,000,000 km. ( every cm represents 60,000
km)
• To demonstrate this effectively we shall go
outside and use a trundle wheel to space out
the distances between the planets.