Download 2- Origin of the Universe

Origin of our Universe:
STARS: a self-luminous celestial body of gas of which
produces energy by means of nuclear fusion reactions.
• A star's color tells us how hot or cold it
is.
• Red stars are not as hot as blue stars.
• Our sun is a yellow star.
• That makes it one of the cooler stars.
Stars Brightness
• A stars brightness is dependent on 3 factors
1. Temperature
2. Size
3. Distance from
the Earth
Our Sun
• 5 billion year old small star (should last 5 more)
• Composed of 75% hydrogen and 25% helium
• Elements in plasma phase (hotter state than gas)
• Energy comes from a Nuclear Fusion Reaction
Sun: joining (fusion) things to release energy
Power Plants: splitting (fission) things to release energy
Fission = split
Fusion = join
Nuclear Fusion Reaction
• Joining two hydrogen to create helium
• Releases large amount of energy
There is obviously more to the Sun then “burning ball of gas”
Layers of the Sun:
Inside
• Core – centre and site of nuclear fusion
Outside
• Photosphere – cooler surface (5500 oC)
sunspots, surface storms – the part we “see”
• Chromosphere – inner atmosphere
small solar explosions (flares), large (prominences)
• Corona – outer atmosphere (1 million oC)
charged gas particles blow outward (solar winds)
“Life Cycle” of a Star
Birth: Stars born out of Nebulae
Nebula – huge clouds of dust and gas
Youth – Middle Age:
• Gravity collapses material into a star that begins
to release energy as a main sequence (MS) star
Scientists categorize MS stars according to mass:
• Small - last longer (billions of years)
• Large - brighter but short-lived (few million yrs)
Nebula
• 99% hydrogen and helium
• 1% iron, rock and ice
Attracted by gravity;
matter clusters together
Actually nebulae captured by NASA space telescopes
Small MS star – Red Dwarf
• Very cool temperatures of their outer gases
Death:
• Forms a cool, dim star called a White Dwarf
• Fades out until it no longer emits light energy
We can’t see most
Red Dwarf stars –
their light is too weak
Medium MS star – like the Sun
• Separated into small-med and large-med
Death:
• Runs out of elements for fusion reaction
• Collapses then swells to produce a Red Giant
• small-med eventually fades out as white dwarf
• large-med explodes as a Supernova leaving
behind a Neutron star
“Pulsar” neutron star
Large MS star
• Extreme energy produced for a short period
• Fuses heavier elements (iron) after lighter ones
Death:
• Collapses then swells to a Red Supergiant
• Gravity collapses the largest into a Black Hole
Stars are in balance: nuclear fusion explodes outwards, large
gravitational force collapses inwards
When the reactor runs out of elements to fuse, gravity wins and the
star collapses and (sometimes) explodes
Birth:
Nebulae
Smallest
main sequence (MS) star
Largest
Medium
Red Dwarf
Red Giant
Red Supergiant
Supernova
Death:
White Dwarf
Neutron star
Black Hole
There is still more to this puzzle, but…this is close enough
Galaxies
• Huge collections of gas, dust and billions of stars
and planets (collected by gravity)
• Constantly in motion
• Many shapes: spiral, elliptical, and irregular
Milky Way Galaxy
• Contains 400 billion stars
• Disc-shaped, with spiral arms – spiral galaxy
We are on one of the arms
• Has a thicker Central Bulge
• Rotates around the bulge
New evidence suggests the “central
bulge” is actually a SUPERMASSIVE BLACK HOLE!
CAN YOU ANSWER THESE QUESTIONS?
S1-4-08:
How do star create energy?
What objects make up our solar system and Universe?
Vocabulary & Concepts
Core
Fusion
Black hole Galaxy
Nebula
Supernova
Origin of our Universe:
OUTCOME QUESTION(S):
S1-4-08:
What objects make up our solar system and Universe?
Vocabulary & Concepts
Asteroid belt
Kuiper belt
Moon
Asteroid
Meteoroid
Meteor
Meteorite Comet
Formation of our Solar System
All matter recycled from past supernova explosions
Outer region of nebula:
• Gases (far from forming Sun) begin to cool
• Cluster together and condense
• Forming the Gas Giants:
Jupiter, Saturn, Uranus and Neptune
Gas Giants appear to lack solid
surfaces, but the gases may
become liquid or solid deeper
towards their dense core
Inner region of nebula:
• Gases in the inner region too hot to condense
• Chunks of iron and rock collide and stick together
• Forming Terrestrial Planets:
Mercury, Venus, Earth and Mars
“Terrestrial” planets have a surface of rock, iron and hard elements
through to the molten core
Terrestrial planets
Mercury
 Closest to the Sun
• Receives sunlight 10x brighter than Earth
• Day temperatures over 400°C
No atmosphere - so night temp fall to
-180°C
• Day (rotation) – 59 Earth days
• Year (revolution) – 88 Earth days
It rotates so slowly that its “year” is less
than 2 “days” long
Venus
 3rd brightest object in the sky
• CO2 atmosphere traps heat (+ 465°C)
• Many volcanoes eject tonnes of sulphur
 Clouds of sulphuric acid
 makes acid rain
• Day (rotation) – 243 Earth days
• Year (revolution) – 225 Earth days
Sun and Moon are brightest objects
Its “year” is shorter than its “day”
Earth
 Atmosphere (N2, O2, H2O) stabilizes temperature
• Ranges from -85oC to +65oC
 Liquid water covers about 70% of surface
• Generally stable – some volcanoes, earthquakes
• Day (rotation) – 1 Earth days
• Year (revolution) – 365 1/4 Earth days
Distance from the Sun is most responsible for
the factors that contribute to Earth’s ability to
sustain life
Mars
 Bright red - iron oxide dirt makes it reddish
• Most studied planet (no signs of life… yet )
 Of all planets, Mars is most like Earth
• Surface temp ranges from -120oC to +30oC
• Day (rotation) – 1 Earth day
• Year (revolution) – 687 Earth days
Although it is dry and barren now,
scientists have evidence that may point to
past glaciers and liquid water
An Asteroid Belt separates the
Terrestrial planets from the Gas
Giants – maybe remains of a totally
smashed older planet
The Gas Giants
Jupiter
 Largest of the planets (11x bigger than Earth).
• Has 63 moons (2006)
 Great Red Spot is a continuous hurricane
• Temp around -160oC
• Day (rotation) – 10 Earth hours
• Year (revolution) – 11.9 Earth years
The coloured bands are gas
clouds being streaked over the
surface as it rotates quickly
Saturn
3 moons and a shadow in this
•
largest of the planets
 Least dense – may not have a solid core
 Rings stretch from Earth to Moon
• 60 moons and 1000 rings (could be crushed moon)
• Day (rotation) – 11 Earth hours
• Year (revolution) – 29.5 Earth years
2nd
picture
Notice the coloured bands on the
surface here too
Uranus
 Rotates on its side
• Extremely cold -210oC
 Has several narrow, dark rings
• Has 27 moons
• Day (rotation) – 17 Earth hours
• Year (revolution) – 84 Earth years
It is now pronounced “ur-an-is” not
“ur-anus”
Neptune
• Only discovered because its gravity “tugs” on
Uranus’s orbit causing changes
 Blue and white – methane in atmosphere
 The Great Dark Spot is a gigantic storm
• Extremely cold -220oC
• Day (rotation) – 16 Earth hours
• Year (revolution) – 165 Earth years
Neptune has some faint rings too,
and 20 moons
Kuiper Belt and the Oort Cloud
• Contain thousands of icy and rocky objects
• Kuiper Belt – Neptune to about 30 to 55 AU
• Oort Cloud – from 5000 AU to 100000 AU
 Pluto and Eris are the best known dwarf planets
found in Kuiper belt
Pluto was
reclassified as a
dwarf planet in
2006
Moon: Large natural object (rock/metal) that
revolves around a planet – also called a satellite.
Humans have visited the moon’s surface
six times between 1969 and 1972.
Planet (2006)
Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune
Pluto
Known moons
0
0
1
2
63
60
27
13
3
Asteroid: Chunk of rock/metal that orbits the Sun
but too small to be considered a planet.
• Asteroid belt in large gap from Mars – Jupiter
• Largest is 1000 Km in diameter
• Asteroid that crosses Earth’s path called a Trojan
Asteroids can get bumped and
smashed into a new orbit and
sometimes that orbit can get
“close” enough to be pulled in by
Earth’s gravity.
Meteoroid: lump of rock that is trapped by Earth’s
gravity and pulled into the atmosphere.
Falling meteoroids bump into air
molecules heating up (friction) until the
air glows – and the meteoroid burns up
and breaks apart.
• Meteoroid that completely burns up - meteor
• producing a streak of light - “shooting star”
The only difference between meteoroid and asteroid is that a
meteoroid is random and an asteroid orbits the Sun
Meteorite: fragment of a meteoroid that doesn’t
burn up and strikes the Earth (space rock).
• Large meteorite collisions make craters
• Westhawk Lake is a crater
Meteorite impact
crater in Arizona
Comet: chuck of ice/dust that orbits the Sun.
• Most originate from the Oort cloud
• Tail: passing by Sun heats trailing gas and debris
then blown out by solar wind - millions of km long
• Some have regular periods of revolution
Halley’s comet: last seen in 1986
it has a orbit period of 76 years
CAN YOU ANSWER THESE QUESTIONS?
S1-4-08:
What objects make up our solar system and Universe?
Vocabulary & Concepts
Asteroid belt
Kuiper belt
Moon
Asteroid
Meteoroid
Meteor
Meteorite Comet