A galaxy contains stars, dust, gas and other celestial bodies bound by gravity. Our galaxy is the Milky Way, which contains the Solar System within it. The Solar System includes the Sun and objects that orbit it, like eight planets. The planets can be divided into inner planets like Earth that are rocky, and outer planets like Jupiter that are gas giants.

1. (C) Francesco Scudellari - Comenius 2010/2011

2. (C) Francesco Scudellari - Comenius 2010/2011
A galaxy is an enormous group of stars,
dust, gas, and other celestial bodies
bound together by gravitational forces.
•Galaxies contain 100,000 to
3,000,000,000,000 stars.
Do you know the name of our galaxy?
Our galaxy is called …

3. (C) Francesco Scudellari - Comenius 2010/2011
Usted está aquí
Voi siete qui

4. (C) Francesco Scudellari - Comenius 2010/2011
The Milky WayThe Milky Way (Vía Lactea) is a spiral galaxy.
Our solar system is a small part of the Milky Way.
Most of the stars that we can see are in the Milky
Way.

5. (C) Francesco Scudellari - Comenius 2010/2011
The Solar System is a small part of the Milky WayThe Solar System is a small part of the Milky Way
galaxy. It includes:galaxy. It includes:
-One medium-sized star (One medium-sized star (the Sunthe Sun))
-A group of planets, dwarf planetsA group of planets, dwarf planets (=planetas(=planetas
enanos),enanos), and satellitesand satellites
-Asteroids and comets-Asteroids and comets
Do you know how many planets are there in theDo you know how many planets are there in the
solar system?solar system?

6. (C) Francesco Scudellari - Comenius 2010/2011
The correct answer is:The correct answer is:
““In the Solar System there are EIGHT planets!”In the Solar System there are EIGHT planets!”
Now let’s speak their names aloud.Now let’s speak their names aloud.

7. (C) Francesco Scudellari - Comenius 2010/2011
In Spanish
Mercurio
Venus
Tierra
Marte
Júpiter
Saturno
Urano
Neptuno

8. (C) Francesco Scudellari - Comenius 2010/2011
In Spanish In English
Mercurio Mercury
Venus Venus
Tierra Earth
Marte Mars
Júpiter Jupiter
Saturno Saturn
Urano Uranus
Neptuno Neptune

9. (C) Francesco Scudellari - Comenius 2010/2011
In Spanish In Italian In English
Mercurio Mercurio Mercury
Venus Venere Venus
Tierra Terra Earth
Marte Marte Mars
Júpiter Giove Jupiter
Saturno Saturno Saturn
Urano Urano Uranus
Neptuno Nettuno Neptune

10. (C) Francesco Scudellari - Comenius 2010/2011
A group of stars,dust and gas bound together byA group of stars,dust and gas bound together by
gravitational forces is called agravitational forces is called a
The galaxy which contains the Solar System is calledThe galaxy which contains the Solar System is called
There is only one star in the Solar System. This star isThere is only one star in the Solar System. This star is
calledcalled
The number of planets of the Solar System isThe number of planets of the Solar System is
LET’S REPEAT
GALAXY
THE MILKY WAY
SUN
EIGHT

11. (C) Francesco Scudellari - Comenius 2010/2011

12. (C) Francesco Scudellari - Comenius 2010/2011
THE PLANETS
•The inner planets (planetas interiores) are the planets
closest to the Sun: Mercury, Venus, EarthMercury, Venus, Earth, and Mars.Mars.
They are made up mostly of rock.
The outer planets (planetas exteriores) are Jupiter, Saturn,Jupiter, Saturn,
UranusUranus,, and NeptuneNeptune.
They are made up of large balls of gases with rings around
them.

13. (C) Francesco Scudellari - Comenius 2010/2011
The Inner
Planets
The Outer
Planets
Mercury Jupiter
Venus Saturn
Earth Uranus
Mars Neptune

14. (C) Francesco Scudellari - Comenius 2010/2011
Our Sun is a star located at the centre of our Solar System.
It is a huge, spinning ball of hot gas and nuclear reactions that
lights up the Earth and provides us with heat (calor).
The sun’s diameter is over 1,400,000 km. It’s
much bigger than any Solar System planet.

15. (C) Francesco Scudellari - Comenius 2010/2011
PLANETARY MOTION. 1: REVOLUTION
The Solar System planets orbit around the Sun
counterclockwise in roughly circular orbits.
This is called revolution
A year (año) is the length of time that it takes a planet to
revolve around the Sun. It depends on the orbit’s length.
For example, the Earth takes 365 days to revolve around the Sun,
while Uranus takes more than 30,000 days (84 Earth’s years)!

16. (C) Francesco Scudellari - Comenius 2010/2011
PLANETARY MOTION.
2: ROTATION
Most planets spin (to spin = girar) on their axis.
This is called rotation.
A day (día) is the length of time that it takes a
planet to rotate on its axis (360º)

17. (C) Francesco Scudellari - Comenius 2010/2011
LET’S REPEAT
We have two different motions of the Solar System
planets:
1 (REVOLUTION). Each planet orbits around the Sun
counterclockwise in a roughly circular orbit.
2. (ROTATION) Each planet spins on its axis.
These two motions are simultaneous, which
means they happen both at the same time

18. (C) Francesco Scudellari - Comenius 2010/2011
And now…SOME QUESTIONS FOR THE CLASS:
How long is the revolution period of Saturn?
Which is the planet with the longest revolution period?
Which is the planet with the longest rotation period? And
the one with the shortest?
Planet
Revolution
period
(in years)
Rotation
period (in
days)
Mercury 0.241 58.6
Venus 0.615 243
Earth 1.00 1.00
Mars 1.88 1.03
Jupiter 11.86 0.414
Saturn 29.46 0.426
Uranus 84.01 0.718
Neptune 164.79 0.6745

19. (C) Francesco Scudellari - Comenius 2010/2011
The correct answers are:
The revolution period of Saturn is 29.46 years.
The planet with the longest revolution period is Neptune
(164.79 years!)
(that means: one Saturn year = 164 Earth years!)
The planet with the longest rotation period is Venus (243
days), while the one with the shortest is Jupiter (0.414 days)

20. (C) Francesco Scudellari - Comenius 2010/2011
CHARACTERISTICS OF THE
SOLAR SYSTEM
Most planets have got one or more
satellites which orbit around them.
For example, the Earth has got 1 satellite orbiting around
it. Do you know the name of Earth’s satellite?

21. (C) Francesco Scudellari - Comenius 2010/2011
SATELLITES
Earth’s unique satellite is called…
THE MOON (la Luna) !
Satellites are also called “moons”.
Some planets have got one or more satellites,
while others have got none.

22. (C) Francesco Scudellari - Comenius 2010/2011
Planet
No. of
satellites
Diameter
Weight
(peso)
Mercury 0 0.382 0.06
Venus 0 0.949 0.82
Earth 1 1.00 1.00
Mars 2 0.53 0.11
Jupiter 63 11.2 318
Saturn 61 9.41 95
Uranus 27 3.98 14.6
Neptune 13 3.81 17.2
And now…SOME QUESTIONS FOR THE CLASS:
Which is the planet with the greatest number of satellites?
And what are the planets that don’t have satellites?
Which is the biggest (in diameter) planet of the Solar System?
And the heaviest? And the lightest? (heavy = pesado, light =
ligero)

23. (C) Francesco Scudellari - Comenius 2010/2011
The correct answers are:
The planet with the greatest number of satellites is JUPITER:
it has got 63!
In the Solar System, there are two planets with no satellites.
They are MERCURY and VENUS.
The biggest planet is JUPITER, which is also the heaviest.
And the lightest is MERCURY.

24. (C) Francesco Scudellari - Comenius 2010/2011

25. (C) Francesco Scudellari - Comenius 2010/2011
• The usual units of measurement (like
meters or kilometers) are too small to
be used in astronomy.
Therefore, astronomers introduced new
units of measurement.
Do you know the names of these units?

26. (C) Francesco Scudellari - Comenius 2010/2011
• ASTRONOMICAL UNIT (AU)
An astronomical unit is equal to the mean
distance from the Earth to the Sun
(about 149,600,000 km)
• LIGHT-YEAR
A light-year is the distance that light can travel in
one year in a vacuum
(just under one trillion kilometers! That is….
10,000,000,000,000 km!!! Or, more precisely,
9,460,730,472,581 km)