The Solar System

The Solar System
The Solar System within the Milky way
Composition of the Solar System
The Solar System is composed by the Sun
and the celestial bodies that orbit it in
• Planets
• Satellites
• Comets
• Asteroids
• Meteors
Celestial bodies’ movements
Is the spinning of a star (s. l.) on its
own rotation axis
Day and night
Is the movement of a star (s. l.)
surrounding a bigger one
Makes seasons
The ecliptic
Also called Ecliptic Plane, it is the imaginary plane where the Earth’s orbit is.
The constellations of the Zodiac lie along the ecliptic.
The Sun
Sun’s identity card
• The closest star to the Earth
• Surface temperature: 6 000 ºC
• Mean distance to Earth: 149 000 km
• Diameter: 1 392 000 km
• Hydrogen (73 %), helium (25 %)
Solar protuberances
• Also called Solar
• Large, bright tongues
extending outward from
the Sun’s surface
• Often loop-shaped
• Top length = 800 000 km
• Maybe caused by
thermonuclear reactions
Size comparison among The Earth,
Jupiter and a Solar Protuberance
The eight Planets
Inner planets
•The Earth
Also called Rocky Planets,
they are closer to the Sun.
Outer planets
The gas giant planets,
beyond the Asteroids Belt.
Made up of hydrogen,
helium and other gases.
They have rings and many
The Inner Planets
• 1 orbit = 88 days
• 1 rotation = 59 days
No moons
Closest to the Sun
Little air
Moon-like surface
Surface temp = -170 ºC
to 430 ºC
• Rocky with iron core
• Orbit = 225 days
• Rotation = 243 days
• No moons
• CO2 and clouds of
• No water
• Hottest planet
• Retrograde (clockwise)
• Rocky with iron core
The Earth
• Orbit = 365 days
• Rotation = 1 day
• 1 Moon
• Atmosphere, hydrosphere
and geosphere
• Life!
• Rocky with iron core
• The blue planet (oceans)
• Orbit = 687 days
• Rotation = 25 hours
• Moons: Phobos and
• Polar icecaps
• Valleys and canyons.
Liquid water weather?
• Atmosphere = CO2
• The red planet (red iron
Water on Mars
Ice cap on Mars’ North Pole, as
seen from Viking 1 space probe
• Mars has got ice caps
• The North Pole ice
cap is made up of
extremely pure water
• In South Pole ice cap
there is a small
portion of CO2
• CO2 frost deposits in
winter and sublimes
in spring
Mons Olympus
The highest mountain in Solar
System is Mons Olympus (25
km high), on Mars
Mars’ surface
Seen from space probe Mars pathfinder
Wings to imagination
Is there a human figure on Mars?
The Outer Planets
• Orbit = 12 years
• Rotation = 10 hours
• 16 moons (Callisto,
Ganymede, Europa,
Amalthea, Io)
• 3 rings
• Covered by coloured
bands of thick clouds
The largest storm we can imagine
Jupiter’s Great Red
Spot is believed to be
a so great anticiclonic (high
pressure) storm, that
three Earths would fit
within its boundaries.
It has been observed
by astronomers for
the last 400 years.
• Orbit = 29.5 years
• Rotation = 11 hours
• 30 moons
• Thousand of rock and
ice rings
• Wind speed = 500
• Yellowish surface
• Orbit = 84 years
• Rotation = 17 hours
• 22 moons
• 11 rings
• Very tilted rotation
• Blue surface
• The coldest planet
• Orbit = 165 years
• Rotation = 16 hours
• 8 moons
• 4 rings
• Great Dark Spot
storm area
Pluto, the no-more planet
Discovered in 1930 by
Clyde Tombaugh, it was
considered a planet until
2006. Now, it has been
demoted to a planetoid,
despite to have its own
satellite, Charon.
• Its ecliptic is 17 º
tilted away from the
other eight planets’
• It hasn’t swept its
orbit out, since it
passes through
Kuiper Belt
Pluto’s ecliptic is deviated 17 º from the average
Solar System’s
The Moon
Moon’s identity card
• The Earth’s only natural satellite
• Mean distance to Earth: 384 400 km
• Diameter = 3 476 km
• Tempeature: -180 ºC to +110 ºC
• Non self-luminous
The Moon phases
• The Moon’s shape appear to change because of
its revolution around the Earth
• The Moon phases are produced by the alignment
of the Moon and the Sun in the sky
• The lit side of the Moon always points to the Sun
The Spanish Moon is a liar: when in waxing crescent (creciente) it seems a
letter D. When in waning crescent (menguante or decreciente), it seems a C.
Why do we always see the same
face of the Moon?
Because the
Moon rotates
on its axis
(red arrows)
every 28 days
completes an
orbit around
the Earth in
the same
Explanation for children (and not so
• Three students needed (two actors and one
• One actor stars the Earth; the other one, the
• The Earth starring will stand, no walking,
rotating on himself, slow for not feeling sick.
• The Moon starring will walk sideways
around the Earth actor, always looking at
him, preventing he to see her back, her dark
• The Moon starring doesn’t think she has
rotated on her axis, since everything she
has done is walk facing the Earth
• But the audience, out of the performance,
realizes that the Moon has really rotated an
entire turn on herself at the same time she
has orbited the Earth, because he has seen
her face and her back
But there is a real dark side of the
…that was
photographed for the
first time on October
7th, 1 959, from the
Soviet space probe
The Moon hasn’t got an
• The Moon’s so little
weight makes it does not
have gravity enough to
retain gases and form an
• Craters caused by
meteors collisions will
stay unchange for ever
since there is no wind or
rain to weather them
Man on the Moon
That’s one small
step for man, one
giant leap for mankind
On July 20, 1 969, at 20:18 UTC,
in the frame of Apollo 11
mission, the Eagle lunar
module landed on the Moon.
Six hours later, the mission
commander, Neil A.
Armstrong, and the pilot Edwin
Buzz Aldrin, Jr. stepped for the
first time our satellite’s surface.
Michael Collins, meanwhile,
orbited the Moon with the
spacecraft, waiting for his
companions to come back on
board and take them all back
home, to Earth.
Moon’s landing conspiracy
• There’s no air on the Moon. Why is the flag flapping?
• Astronaut and spaceship shadows’ don’t match
• There are no stars on the background
Not only planets
Rocky celestial bodies that orbit the Sun. Its
size can vary from little stones to dwarf
Asteroids are distributed in three areas
within Solar System:
• Asteroids Belt
• Kuiper Belt
• Oort Cloud
The Asteroids Belt
• Situated between Mars and Jupiter
• Houses 90 % of Solar System’s asteroids
• Thought to be a planet destroyed because of a collision
The Kuiper Belt
• Situated beyond Neptune
• Responsible for Pluto’s demotion to planetoid
The Oort Cloud
• Celestial bodies made up of ice, dust and
• Mostly coming from Oort Cloud
• Elliptical orbits around the Sun
• Non self-luminous, but reflect the Sun light
Structure of a comet
Frozen water and gases.
When melting, it forms
coma and tail
Giant cloud of dust and
gases, surrounding the
Electrically charged
gases and dust. Always
pointing away from the
Some historical comets
• Great Comet of 1882. The brightest comet in
modern History. Waiting again for him in 2642
• Great Comet of 1843. The longest tail: 300
million kilometres. Period = 737 years
• Halley. Registered since 240 BC. In 1910, the
Earth passed throuhg its tail
• Hale-Bopp. In 1995, its two tails were visible with
a naked eye
• Hyakutake. 1996
Two-tailed Hale-Bopp
Three-tailed Donati (1858)
Anti-tailed Arend-Roland (1956)
Was the Star of Bethlehem a
The Florentine painter Giotto di
Bondone, who was a witness of
Halley Comet in 1301, painted
The adoration of the Magi,
where the Christmas Star is
shown as a comet.
Several efforts have been
made in order to link the Star
with inusual astronomical
events, such as comets,
supernovae or an extraordinary
conjunction of Jupiter and
Tom Sawyer and Huckleberry Finn
were born and gone with a comet
Mark Twain wrote in his autobiography: I came in with Halley's Comet in
1835. It is coming again next year, and I expect to go out with it (…) Both
went out together in 1910.
• Meteoroids are formed from asteroids
collision or breaking up
• Meteors and meteoroids that get into
Earth’s atmosphere are burnt because of
friction against air
• Streak of light left behind them
• Shooting stars
Meteor showers
When the Earth passes
through a debris
cloud left by a comet.
Do you know any
meteor shower?
Every August, the Perseids or Tears
of St. Lawrence, shine on the sky.
Although they seem to come from
Perseus constellation, really are linked
to comet Swift-Tuttle.
Some meteor craters on the Earth Surface
Meteor Crater. Winslow, Arizona
Chicxulub, Mexico
Tunguska, Siberia
Bosumtwi, Ghana
Did the dinosaurs become extinct
because of a meteor collision?
Some scientists
hold that
became extinct
65 Million Years
ago because
a 10 km-diameter meteor collided with
the Earth, causing a 90 meters high
waves tsunami and throwing to the
atmosphere such an amount of dust
and glowing stones that the cloud
darked sunlight for months. Plants and
animals would die, only surviving the smallest ones.
They claim the exact impact place to be Yucatán peninsula, in Mexico. There should
be a crater, 80 km-diameter and 600 meters deep under the ocean. It is also claimed
an unusual amount of iridium to be found between geological Cretaceous and Cenozoic
Era layers all over the World.
Could a celestial body hit the
• It is possible,but the huge Jupiter gravity
force should attract them towards it
• International space research agencies
have developed several programs for
monitoring asteroids and meteor tracks
Near Earth Objects Program
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