Unit 1. The universe
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Transcript of Unit 1. The universe
THE UNIVERSE
GALAXIES
•Galaxies are a vast collection of stars, dust and gases.
•They appear in groups called galaxy clusters. (Local Group is our galaxy cluster)
•Our galaxy is the Milky Way.
MILKY WAY
What shape is the Milky Way?Can we see the Milky Way from Earth as it is shown in the image?
Why or why not?
1. WHAT IS THE UNIVERSE LIKE?
Geocentric theory
2nd century B.C.
Proposed by Ptolomy.
The Earth was thecenter of theUniverse.
The Sun, Moon and planets orbited theEarth.
1. WHAT IS THE UNIVERSE LIKE?
Heliocentric theory
In 1542
Proposed by NicolausCopernicus
The Sun was the center of the Universe
¿ASTRONOMY OR ASTROLOGY?
WHEN DID THE UNIVERSE BEGIN?
BIG BANG
17.000 m.y. ago
IS THERE ANY EVIDENCE?
2. HOW BIG IS THE UNIVERSE?
WHAT UNIT OF MEASUREMENT DO
ASTRONOMERS USE?
Astronomical unit (AU) is the distance between the Earth and the Sun= 150 million kilometres.
Express the distance of Mercury, Mars and Pluto from the Sun in kilometres:
Mercury: 0,4 AU =
Mars: 1,5 AU=
Pluto: 39,4 AU=
Light year. It is the distance light travels in a year. Light travels 300,000 km per second.
0,4 x 150.000.000 = 60.000.000 Km
1,5 x 150.000.000 = 225.000.000 Km
39,4 x 150.000.000 = 5.910.000.000 Km
This distance is equivalent to roughly
9,461,000,000,000
4. WHAT MAKES UP THE SOLAR SYSTEM…?
SUN
It’s a medium-sized star.
The Sun consists mainly of two gases: 75% hydrogen (H) and 25% helium (He).
Temperature of the nucleus 15.000.000 ºC. So hot inside that it emits heat and light through nuclear fusion.
It rotates on its axis in an anticlockwise direction (once every 25-30 days)
It was formed when clouds of gases pull together by gravitational forces.
What is the name of the process that takes
place inside the Sun’s nucleus?
What happens during this process?
PLANETS
Planets are spherical bodies which revolve around the Sun.
They move in elliptical orbits.
Mercury, Venus, Earth and Mars are made up mainly of rock. (Rocky planets)
Jupiter, Saturn, Uranus and Neptune are made up mainly of gases. (Gaseous planets)
Rocky planetsor inner planetshave a crust and a mantle made of rock and a metallic core.
Gaseous planetsor outer planetsare made up mainly of gas.
Elliptical orbits
WHICH ARE THE INNER PLANETS?
Mercury
Mercury is the closest planet to the Sun
It is the smallest planet in the Solar System
It has no natural satellites.
It has no atmosphere
There are lots of craters on its surface
Huge differences in night and day
temperatures (From -170ºC to 480ºC)
Venus
Venus is similar in size to Earth.
It has an extremely dense atmosphere which
consists mainly of carbon dioxide (CO2). This
thick atmosphere makes it the hottest planet
of the planetary system, with surface
temperatures over 450°C.
Venus has no natural satellites.
One day in Venus lasts more than one Earth
year.
Earth
Earth is the largest and densest of the inner
planets
It’s the only planet known to have life.
Its liquid hydrosphere is unique among the
inner planets. (Average surface temperature
= 15ºC)
Earth's atmosphere has been altered by the
presence of life to contain 21% free
oxygen. (78% N2)
It has one satellite, the Moon.
Mars
Mars is smaller than Earth and Venus.
It has a thin atmosphere that contains 95%
carbon dioxide, so it’s not breathable.
It’s surface resemble the Earth’s rocky
deserts.
Mars has two tiny natural satellites
(Deimos and Phobos).
WHICH ARE THE OUTER PLANETS?
Jupiter
Jupiter is the largest planet of the Solar System.
It is composed largely of hydrogen (90%) and
helium (10%).
Jupiter has more than 60 known satellites.
The four largest satellites are Ganymede, Callisto,
Io, and Europa.
There are bands of different coloured clouds
around the planet, parallel to the equator.
Saturn
Saturn, famous for its extensive ring
system made of ice, small rocks and dust
particles.
Its composition is very similar to Jupiter’s.
(97% Hydrogen, 3% Helium)
Saturn also has more than 60 known
satellites. The largest one is Titan.
Uranus
Uranus is the lightest of the outer planets.
It’s a frozen planet, with very low surface
temperatures.
One unique feature of Uranus is its axial tilt.
The planet rotates on its side with a tilt over
ninety degrees to the ecliptic.
It also has a ring system
Uranus has 27 known satellites.
Neptune
Neptune is slightly smaller than Uranus.
It has 13 known satellites. The largest one
is Triton.
Elliptical orbits
DW
ARF
PLANETS
They are spherical bodies that orbit the Sun.
They are smaller than planets.
They have not cleared the area in which they orbit.
In the
Asteroid belt
Further than Pluto
DWARF PLANETS Asteroid belt
SM
ALL
SOLAR
SYSTEM
BODIES
These are other celestial bodies that orbit the Sun.
They include asteroids, comets and satellites.
Asteroids
Between the orbits of Mars and Jupiter is located
the Main Asteroid Belt. Asteroids are rocky
bodies that range in size from hundreds of
kilometres across to microscopic.
Comets
Comets are composed largely of volatile ices, dust and fragments of rock. When a comet enters the inner Solar System, its proximity to the Sun causes its icy surface to sublimate and ionise, creating a coma, which is a long tail of gas and dust often visible to the naked eye.
Short-period comets, such as Halley's Comet, are believed to originate in the Kuiper belt (30-1.000 A.U. from the Sun), while long-period comets, such as Hale-Bopp, are believed to originate in the Oort cloud (60.000 A.U. from the Sun)
Satellites or moons
They orbit some planets.
The Earth’s natural satellite is the Moon.
Trans neptunian regions:
Kuipert belt (30-1000 AU) and Oort cloud (60.000 AU)
PLAY THESE GAMES
http://www.educaplay.com/es/recursoseducativos/102
3849/solar_system.htm
http://www.educaplay.com/es/recursoseducativos/102
3852/classify_planets.htm
http://www.educaplay.com/es/recursoseducativos/102
3853/which_planet_.htm
HOW DO THE PLANETS MOVE?
http://esminfo.prenhall.com/science/geoanimations/
animations/01_EarthSun_E2.html