the universe

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1. The history of knowledge of the universe.2. The celestial bodies in the universe.3. Dimensions and distances in Astronomy.4. The stars and the galaxies.

4.1. The stars.4.2. The galaxies.

4.2.1. Our galaxy: The Milky Way.

5. The Solar System.

Pepi Jaramillo RomeroDpto. Física y Química

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1. The history of knowledge of the universe.

The Sun, the moon and the five known planets ( Mercury, Venus, Mars, Jupiter and Saturn ) all revolved around the Earth

Ptolomy suggested a GEOCENTRIC ASTRONOMIC MODEL

They were well-known in ancient times because they can be easily seen withthe naked eye and their movements are easily differentiated from stars which are in afixed position.

SECOND CENTURY



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Copernicus

Published his HELIOCENTRIC MODEL1543

However, hundreds years before the Greek astronomer Aristarchus of Samos

sugestted that the Earth revolved around the Sun

The planets revolved around the Sun



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17th CENTURY

In 1609 Galileo used a telescope for the firsttime to observe the

night sky. This was thebirth of modern

astronomy.

At the end of the same century, Isaac Newton built the first telescope using

mirrors instead of lenses. Newton published his book The Principles of

natural Philosophy in which he explained the laws governing the

movement of the planets.



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ACTIVITY

CTIVITY ONEFind some information

about the origin of the universe,especially about The Big BangTheory.Please, write a summary usingyour own words.REMEMBER: DO NOT COPY ANDPASTE.


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2. The celestial bodies in the universe.

THE UNIVERSE Pepi Jaramillo RomeroDpto. Física y Química

The celestial bodies in the

universe are verydiverse. The

properties of a planet, for

example, are verydifferent to those

of a star, so thetemperature is

very high on a star(millions of

degrees Celcius).


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TYPES OF CELESTIALS BODIES

PLANETS

COMETS

SATELLITES

ASTEROIDS

CLUSTER OF GALAXIES

STARS

GALAXIES


DWARF PLANETS


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Like the Earth, which is the planet we live on.


PLANETS

The planetsshine by

reflectinglight fromthe Sun.



DWARF PLANETS

We've been asking that question at least since Greekastronomers came up with the word to describe the bright pointsof light that seemed to wander among fixed stars.

Many disagreed in 1930 when Pluto was added as our solarsystem's ninth planet. The debate flared again in 2005 when Eris --about the same size as Pluto -- was found deep in a zone beyondNeptune called the Kuiper Belt. Was it the 10th planet? Or are Erisand Pluto examples of an intriguing, new kind of world?

What is a planet?



DWARF PLANETS

The International Astronomical Union decided in 2006 that anew system of classification was needed to describe these newworlds, which are more developed than asteroids, but differentthan the known planets. Pluto, Eris and the asteroid Ceres becamethe first dwarf planets. They are orbiting the sun in zones of similarobjects such as the asteroids.

Our solar system's planet count now stands at eight. But the lively debate continues as we continue to explore and make new discoveries.



DWARF PLANETS


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Like the moon, which is the Earth’s only natural satellite.


SATELLITES


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Which orbit around the Sun on a very longtrajectory.


COMETS



COMETSThe comet Halley willreturn in 1758


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ASTEROIDSRocky bodies which are smaller than planets, very often irregular in shape, and which orbitaround the Sun.



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Like the Sun which continuously radiates energyinto the space around them


STARS


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GALAXIES

Groups of tens orhundreds of

thousands of stars. Itis thought that theuniverse contains

approximately 100 000 galaxies.



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CLUSTER OF GALAXIES

Made up of manydifferent galaxies.


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3. Dimensions and distances in Astronomy.

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The size of the celestial bodies is quite incredible as is the distancebetween these ones too.

EXAMPLEA space ship travelling at 40 000 km/h (usual speed) would take 100 000 years to reach the nearest starto the Sun.

This is why we use the term LIGHT YEARS when we want to talkabout astronomics distances.

LIGHT YEARS Distance covered by light in a year.

C = 300 000 km/s


3. Dimensions and distances in Astronomy.

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Astronomer also use another unit

Distance between the Sun and the Earth

ASTRONOMICAL UNIT (A.U.)

1 A.U. = 150 000 000 km


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4. The stars and the galaxies.4.1. The stars.

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If we look at the night sky on a clear night and well awayfrom the city light we can see hundreds of small lights which

seem to be twinkling.

STARS

Stars have differents characteristics

LIGHT

SIZEBRIGHTNESS

COLOUR



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COLOUR

Not all stars are white as they at first appear. More careful inspection reveals that stars come in a wide

range of colours. Some are bluish, reddish, orange. The Sun is a yellow star. The colour of a star depends on its surface temperature, with the coolest stars being the

reddest and the hottest ones the bluest



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The stars come in a wide range of sizes. The largeststars, known as giants and supergiants, are hundredsof times the diameter of the Sun. In fact, the Sun is a medium sized star. For example, Betelgeuse, a star in

the constellation of Orion is 600 times bigger than theSun. On the other hand, Sirius B in the constellation of

Canis Major is 100 times smaller than the Sun.

SIZE



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Star brightnesses are expressed in terms of magnitudes. This system was started by the Greek

astronomer Hipparchus in the second century B.C. He divided the stars into six categories of brightness, from

the brightest stars (first magnitude), to the fainteststars that he could see (sixth magnitude). Nowadays

stars brightnesses are measured to the nearesthundredth of a magnitude by sensitive instruments

known as photometers.

BRIGHTNESS



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Some stars emits more light than others. Two starsemitting the same amount of light will not be as bright

as each other if they are at different distances fromthe Earth.

LIGHT



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Constellations come in many different shapes and sizes. Thetradition of dividing the sky into constellations began

thousands of years ago when ancient people assigned certainstar patterns the names of their gods, heroes and fabled

animals.

The sky is divided up into 88 areas, known as constellations, which serve as a convenient way of locating the position of

objects in the sky.

CONSTELLATIONS



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The brightest and biggeststars are shown on a

PLANISPHERE



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ACTIVITY

CTIVITY TWOTry to find the constellatios of

Orion, Leo, Cassiopeia, Ursa Major,Ursa Minor, Polaris star and Lepus.

Can you find all the stars onthe planisphere by looking at thenight sky in your region?

Why do we need very darknights to be able to observe the star?


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4. The stars and the galaxies.4.2. The galaxies.

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Galaxies extend into space as far as the largest telescopescan see. Each is a collection of millions or billions of stars heldtogether by the mutual attraction of gravity.

Galaxies are classified according to their shapes. Thereare two main forms:

ELLIPTIC

SPIRAL

IRREGULAR

More or less spherical

A flat disc with several arms comingout of the nucleus of the spiral

They have not specific shape


4. The stars and the galaxies.4.2. The galaxies.


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All the stars visible to the naked eye are part of anenormous system of at least 100 000 million stars known as TheMilky Way. Our Galaxy has a spiral shape. The entire Galaxy isrotating; our Sun takes about 250 million years to complete oneorbit around the centre of the Galaxy.

The nearest galaxy to our own is Andromeda which ismore than two million light years away. This means that whenwe look at this galaxy we are seeing it as it was more than twomillion years ago.


4. The stars and the galaxies.

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ACTIVITY

CTIVITY THREEWhat type of galaxy is The

Milky Way ?Are there more stars in the

swirls spiralling out from the centreor near the nucleus ?


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Our planetary system is formed 5000 million of years agofrom nebulas’ gases and dust. The Sun is in his centre and it ismade up of two gases: Hydrogen and Helium. The planets,satellites, comets and asteroids revolve around the Sun.

The comets and the asteroids are smaller bodies. Cometsshow their spectacular tails when they come close to the Sun.Many are concentrated in a region located between the orbits ofMars and Jupiter known as the ASTEROID BELT.



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The planets revolve around the Sun in eliptical orbits. Theplanets which are farthest away revolve more slowly and takelonger to complete a full revolution.

TERRESTRIAL PLANETS

(They have a solidsurface)

The planets can be classified

GAS GIANT PLANETS(They do not have a

solid surface)



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TERRESTRIAL PLANETS

The closest planet to theSun, only slightly larger than Earth’smoon. Like the Moon, Mercury hasvery little atmosphere to stopimpacts, and it is covered withcraters. Mercury's dayside is super-heated by the Sun, but at nighttemperatures drop hundreds ofdegrees below freezing. Ice may evenexist in craters. Mercury's egg-shaped orbit takes it around the sunevery 88 days.


MERCURY



The brightest planet, Venus,outshines every star in the sky. It isfrequently seen rising before the Sunin the morning sky, when it ispopularly known as the morning star,or setting in the evening twilight whenit is termed the evening star. Venus isa dim world of intense heat andvolcanic activity. Similar in structureand size to Earth, Venus' thick, toxicatmosphere traps heat in a runaway"greenhouse effect."

VENUSTERRESTRIAL PLANETS


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TERRESTRIAL PLANETS

Earth is an oceanplanet. Our home world'sabundance of water -- and life --makes it unique in our solarsystem. Other planets, plus afew moons, have ice,atmospheres, seasons and evenweather, but only on Earth doesthe whole complicated mixcome together in a way thatencourages life -- and lots of it.


EARTH


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TERRESTRIAL PLANETS


MARSMars is a cold desert world.

It is half the diameter of Earth andhas the same amount of dry land.Like Earth, Mars has seasons, polarice caps, volcanoes, canyons andweather, but its atmosphere is toothin for liquid water to exist for longon the surface. There are signs ofancient floods on Mars, butevidence for water now existsmainly in icy soil and thin clouds.


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GAS GIANT PLANETS

Jupiter, the most massiveplanet in our solar system -- withdozens of moons and anenormous magnetic field -- formsa kind of miniature solar system.Jupiter does resemble a star incomposition, but it did not growbig enough to ignite. The planet'sswirling cloud stripes arepunctuated by massive stormssuch as the Great Red Spot, whichhas raged for hundreds of years.


JUPITER


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GAS GIANT PLANETS

Adorned withthousands of beautifulringlets, Saturn is uniqueamong the planets. All fourgas giant planets have rings -made of chunks of ice androck - but none are asspectacular or ascomplicated as Saturn's. Likethe other gas giants, Saturnis mostly a massive ball ofhydrogen and helium.


SATURN


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GAS GIANT PLANETS


URANUSUranus is the only

giant planet whose equator isnearly at right angles to itsorbit. A collision with an Earth-sized object may explainUranus' unique tilt. Nearly atwin in size to Neptune, Uranushas more methane in its mainlyhydrogen and heliumatmosphere than Jupiter orSaturn. Methane gives Uranusits blue tint.


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GAS GIANT PLANETS


NEPTUNEDark, cold and

whipped by supersonic winds,Neptune is the last of thehydrogen and helium gasgiants in our solar system.More than 30 times as far fromthe sun as Earth, the planettakes almost 165 Earth years toorbit our sun. In 2011 Neptunecompleted its first orbit sinceits discovery in 1846.


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ACTIVITY

CTIVITY FOURWhat do you think caused the

craters on the surface of Mercury ?Why do the photograghs of

Pluto show very little detail?Could we send a spaceship to

land on Jupiter or Saturn? Explainyour answer.



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ACTIVITY

CTIVITY FIVEWhich planets take the longest

in orbiting the Sun ?Which planets have the longest

days and which planets have theshortest days?

Which planets are a similar sizeto the Earth?


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