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4.
PLANETS IN THE SOLAR SYSTEM
The inner and outer planets are all different from each other: different distances
from the Sun, different revolution and rotation periods, size and the number of
satellites.
This table shows some characteristics of the planets in the Solar System:
Planet
Distance
from the Sun
1
Revolution
period
2
Rotation
period
2
Diameter of
equator
3
Number of
satellites
Mercury
0,39
88 days
59 days
4880
0
Venus
0,72
224,7 days
243 days
12104
0
Earth
1
365,26 days 23 h 56 min 12756
1
Mars
1,52
687 days 24 h 37 min 6787
2
Jupiter
5,2
11,86 days 9 h 50 min 142800
63
Saturn
9,54
29,46 days 10 h 14 min 120000
61
Uranus
19,2
84,01 days 17 h 14 min 51800
27
Neptune
30,1
164,8 days 16 h 7 min 49500
13
(1) Average distance in AU (2) According to terrestrial values (3) Average values in km
4.1.
Inner planets
The
inner planets
are small, have very little or no atmosphere and have a
rocky surface.
Mercury
Venus
Earth
Mars
Mercury is named after the
messenger of the Roman gods.
It has no atmosphere and
because of this its average
temperature varies, depending
on exposure to the Sun
(-170 ºC at night and 425 ºC
during the day).
Mercury does not contain
water.
It has 0.055 times the mass of
Earth. On Mercury, we would
weigh 0.37 times more than
we weigh on Earth.
Venus is named after the
Roman goddess of love and
beauty.
It has a very dense
atmosphere that generates a
greenhouse effect. Its average
temperature is 480 ºC.
Venus could contain water
vapour.
It has 0.815 times the mass of
Earth. On Venus, we would
way weigh 0.88 times less
than we weigh on Earth.
Our planet is named after
Tellus or Terra, the Roman
goddess of the Earth.
Earth’s atmosphere has
greenhouse gases that allow
the planet to maintain an
average temperature of 15 ºC.
Earth is the only planet in the
Solar System where water is
found in all three states. It is
also the only planet where life
has been found.
It has a mass of 6 x 4
24
kg.
Mars is named after the
Roman god of war.
In the past, its atmosphere
was possibly more compact,
but now it is very light. Its
average temperature is -63 ºC
Mars has ice at both poles.
It has 0.108 times the mass
of Earth. On Mars, we would
weigh 0.38 times less than we
weigh on Earth.
Key structure
2nd conditional
would + past participle
On Venus, we would weigh…
