Unit 8, anaya, universe and earth

1. 8. The Universe and the Earth
BIOLOGY AND GEOLOGY. ANAYA 1ST ESO.
Ana Rupérez Romero

2. Ancient civilizations
 Mythology
 Earth motionless and flat
 Sky was a dome with the stars.
Greeks
 Earth is spherical body
 Earth floats in space like other celestial bodies

3. Geocentric
model
 Ptolemy in 2nd century
AD
 Earth round and at the
center of the universe
 Other celestial bodies
revolved around
 Sphere with fixed stars
 Planets known: Earth,
Venus , Mars, Jupiter
and Saturn

4. Heliocentric
model
 Aristarchus and Copernicus
 The Sun is at the center of the
universe
 The other planets revolve
(orbit) around the Sun.
 The Moon orbits the Earth.
 The Stars are on a fixed
Sphere.

5. Current idea of universe
The sun is not at the center
of the Universe, only at the
center of the Solar System.
The orbits of the planets are
not circles, but elipses.
The stars are not in a fixed
sphere but in a Galaxy.
The universe is all MATER,
ENERGY AND TIME
The Universe is expanding:
galaxies are separating
Occupies an enormous
space
The BIG BANG was the first
explosion.

6. Some definitions:
 Universe: All matter energy and time that exist. It occupies
an enormous space (100 000 million light years)
 Galaxies: collections or stars and nébulas.
 Nebulas: clouds of dust and gas. They are the places where
stars are born and they can also come from explosions of
stars.
 Stars: are enormous spheres of matter that emit energy (with
nuclear reactions transforming hydrogen into hellium)
 Solar systems: formed ussually by one star, planets, moons,
asteroids, comets, dwarf planets….
 Big Bang: is the name for the first explosión that created the
universo. Galaxies are moving away from each other. The
universe is getting bigger and expanding. It happened
around 14 000 million years ago.

7. Relative sizes
 Video

8. Distances in the universe
 1 Astronomic Unit: AU is 150 000 000 km. 150 million km
 Speed of light: 300 000 km/s
 1 year has: 60*60*24*365= 31 104 000 seconds
 31 104 000s x 300 000 km/s is the distance that light covers in 1 year
 Light year: 9 500 000 000 000 km, 9,5 billion km
 Closest star to the Earth: Alpha Centauri (4,3 light years>>
41,32billion km)

9. Our solar system
 Located in the Milky Way (100-400 billion stars)
 The Milky Way belongs to the Local Group (20 galaxies)
 The Local Group is in the Virgo Supercluster.
Celestial bodies in the Solar System: The Sun
 Planets (8)
 Satellites
 Dwarf planets
 Asteroids
 Comets

10. The Sun video

11. The sun
 Medium sized star.
 Located in one of the spiral arms of the Milky Way
 Movements: rotation around its axis and with the Galaxy.
 Sends energy in forms of heat and light. Also sends solar
wind (with particles) video of solar wind.
 Sun age: 5000 million years
 Sun will die in 4500 million years

12. Types of stars

13. Planets
 Spherical celestial bodies that orbit a star.
 Reflect sunlight (they can´t produce their own light)
 They travel in elliptical orbits around the sun
 All the orbits are located in the same plane: the ecliptic
plane
 ROCKY or INNER: Mercury, Venus, Earth and Mars
 Small, made of rock, weak atmosphere.
 GAS or OUTER: Jupiter, Saturn, Uranus, Neptune.
 Big, small solid nucleus, large and thick atmosphere, many
satellites and rings.

14. Planets of the solar system
Rocky or inner planets:
• Rocky surface
• Dense materials
• Atmospheres tenuous (tenues)
• Smaller in size
• Mercury, Venus, Earth and Mars
Gaseous or outer planets
• Further
• Low density substances in gaseous
state
• Atmospheres very thick covering a
tiny solid nuclei
• Size very large and a slower speed

15. Satellites
 Spherical (or not) bodies that orbit a planet.
 Rocky planets have none, one or two satellites.
 Venus and Mercury: none
 Earth: one (the Moon). Mars:two (Phobos and Deimos)
 Gas planets have many satellites.
 Jupiter: more tan 60. Galilean Satellites are 4: Callisto, Europa,
Io and Ganimedes.

16. More definitions
 Dwarf planets: spherical bodies (Pluto and Ceres) that orbit
a star but their orbits are not free of other objects.
 Asteroids: Irregular rocky bodies that orbit around the Sun
(in the Asteroid Belt or Kuiper belt). The trajectory can
change.

17.  Comets: small bodies made up of rock and ice. Come from
the Kuiper belt. Very elliptical orbits. The fragments can
become meteorites.
 Meteor shower or shootting stars

18. Our solar
system
Watch the following videos about our solar
system:
The origin of the solar system:
http://www.watchknowlearn.org/Video.aspx?Vid
eoID=55507&CategoryID=2813

19. Solar System:
 Formation of Solar System: video 1(Stephen Hawkins), video 2

20. Formation of the solar system
1. The nebula begins to condense and revolve.
2. The rotation caused the nebula to take the shape of a flat disc:
the protoplanery disc (most matter at the center)
3. The matter at the center concentrates more and more>>
pressure and temperatura make nuclear reactions>>> the Sun
is formed.
4. The rest of the materials were send outside the center and
revolved around the Sun at different distances>>
Planetesimals were formed (the heaviest one close to the Sun
will form rocky planets and the lighter ones will form the gas
planets.)
5. Planetesimals attract the materials in their orbits and formed
larger and larger planetesimals that eventually became planets.

22. Crab nebula
 5th July 1054. The story of a supernova.
 Crab nebula is the first supernova that has been witnessed in the whole
world (China, America, native Anasazi..). During the explosion it could be
seen even at daytime and later stayed visible for 22 months
 Crab nebula is 6300 light-years away from us. Therefore, the real explosion
was in 5246 before Christ although its light didn’t arrive to us until later.
 Explosion
Supernova
5246 BC
Year 0
Observed
1054 AC

23. Some constellations of the Milky Way
 Constellation: group of stars forming a recognizable pattern (drawing)
that is named after the form of the figure (mythological figure). The sky is
divided into 88 regions called constellations.
 Stars in a constellation are not closed together, they look together
because apparently have the same brightness.
 Orion

24. Finding the North: Pollaris
 Ursus Major or Big Dipper is one of the constellations that can be
seen the whole year because they are close to Polaris. They are named
circumpolar.
 Other circumpolar constellations are:
 Casiopea, Perseus, Draco or Cepheus
Stars in a costellation are at
different distances from us.

27. Meanings of the names of the planets and
curiosities more curiosities
PLANET CURIOSITY
Mercury
God Messenger of Roman gods. Faster. Smaller planet, no atmosphere, no moons, 88 days
revolution, 59 days rotation. 430ºC at day, -170 degrees at night
Venus
Godess of love and beauty. Clouds of carbón dioxide. White and dense atmosphere. Surface very hot.
Lava. It rains sulphuric acid. Morning star. Evening star. Second brightest object after the moon.
Similar size to Earth. High greenhouse effect. It rotates in the other direction. Impact of something
turned it upside down
Earth
Life. Water 3 states (solid, liquid, gas) . Temperature of 15 degrees of average. Axis tilted 23,5
degrees>> seasons
Mars
God of war. Red planet. Smaller than Earth. No internal activity. Olympus (22km). Rests of wáter. Ice
caps. Pathfinder explore>> bacterias. Future colony, Two moons: Phobos, Deimos
Jupiter
King of Gods. Bigger. Storm 200 years. Faster rotation (10hours) Magnetosphere. Aurora. 4 main
moons: Europa, Callisto, io, Ganymedes. Discovered by Galileo with telescope (1610) Atmosphere
with stripes. Hydrogen and hellium. Weight higher than all the other planets together
Saturn
Second big planet. Titan. Rings of ice and gas.1km thick. More tan 60 satellites. Titan has atmosphere.
Very light, it would float. Is the farthest planet you can see without telescope.
Uranus
God of air. Spins like from a side, like a Rolling ball. Blue. Several moons. Rings very thin
Neptune
God of oceans and wáter. Blue. Farthest planet. Similar to Uranus in size

28. Our planet: the Earth
The movements of the Earth
The Earth moves in
two different ways:
• Rotation.
• Revolution.
• https://www.youtube.com/watch?v
=lkWyM-M8o0c

29. Rotation
 The Earth rotates (spins) on its
own axis.
 Its axis is an imaginary line
between the North Pole and the
South Pole.
 The axis is tilted 23.5º with
respect to the perpendicular line
to the ecliptic plane

30. The consequences of rotation
The rotation of the Earth
every 24 hours causes day
and night.
• It is day time on the
side of Earth where
the sun shines.
• On the other side of
Earth is night.
https://www.youtube.c
om/watch?v=R3jr0Da
V8N8

31. The consequences of rotation
Rotation sense is
counterclockwise.
Sunrise or dawn: when the sun
first appears in the
morning>> EAST
Sunset or twilight: the sun
disappears in the evening>>
WEST

32. Revolution
The Earth revolves around the Sun.
The Earth takes 365 days, 6 hours and 9 minutes to
complete the revolution = a sideral year.

33. The consequences of revolution:
the seasons
Two factors cause the seasons:
• The revolution of the Earth around the
Sun
• The tilt of the Earth’s axis of rotation
respects to the Plane of the Ecliptic.
• Video on seasons (2 min)
• https://www.youtube.com/watch?v=rc
quRMaVSKU&t=11s

34. Solstices equinoxes and seasons

35. Solstices and equinoxes
Solstices: Maximum
difference between day
and night.
Equinoxes: Day
and night have the
same length.
 Sun hits perpendicular to the
equator.
 March, 20/21
 September 22,23
 Sun is at the highest or lower
point.
 December, 21/22 is the shortest
day
 June, 21/22 is the largest day

36. The seasons in the Northern
Hemisphere
During the summer in the northern hemisphere, the temperature
is higher because there are more hours of daylight and because
the Sun rays hit the Earth surface at an angle of 90º. During the
winter, Sun rays are more tilted and that´s why is colder.
In the South Hemisphere is the opposite.

37. During the seasons, temperature changes
depending on angle at which the Sun’s rays hit
the Earth.

39. Our satellite: the Moon
Movements of the moon:
 Rotation of the moon: It takes 27.3 Earth days to rotate on its axis.
 Revolution of the moon: Moon orbits the Earth every 27.3 Earth days.
 Libration (see the gif on this page. The libration is that Little movement)
 Same side of Moon always facing the Earth. (there is a dark side of the
moon we never see)
 Video on Moon phases
 Origin and formation of the moon

40. Phases of
the moon
Moon calendar
Newmoon
First
quarter (crescent
moon)
Full moon
Lastquarter
or Third quarter
(decreasing moon)
The 4 phases repeat every 29
days (7 days each main phase)

42. Eclipses
 Eclipses:
 Solar eclipse; the Moon is alligned with the Earth and the Sun.
 Lunar eclipse: the Earth is between the Sun and the Moon.
https://www.youtube.com/watch?v=kgbK2FZFFdw&t=83s

43. Tides
 Tides:
 Periodical rise and fall of the sea level.
 They are caused by the gravitational force of
the Moon and, to a lesser extent, the Sun on
the water masses of the Earth.
 https://www.youtube.com/watch?v=9rkfk9TJ52I
 Images of high/low tides

44. Spring tides (mareas vivas) and
neap tides (mareas muertas)

45. Tides
 Neap tides (mareas
muertas)>> First and
last quarters. Little
difference between high
and low tides sea levels.
 Spring tides (mareas
vivas) >> Full moon and
new moon Big
difference between high
and low tides sea levels.