Transcript Space exploration - Menihek Home Page

Unit 2 (textbook Unit 4)
SPACE EXPLORATION
KWL Chart
 Copy down the following chart (make it about a page long):
KNOW
WANT TO KNOW LEARNED
 First, write what you already know about space (point form)
– anything you can think of that you know for sure.
 Then, write what you want to know about space that you
don’t know already.
 You will keep the table in your portfolio. At the end of the
unit, you will take your chart out again and write down
what you’ve learned.
What is all that stuff up
there?
 Any natural object in space such as a planet, a
moon, an asteroid, a comet or a star is called
a celestial body.
 Early civilizations would make note of the
movement of celestial bodies so that they
would know when a good time to plant their
crops would be. The stars and planets served
as the first calendars.
Constellations
 Groups of stars
that make a
pattern are called
constellations.
Ancient Greeks and
Romans would
label the
constellations after
characters from
their mythologies.
Common Constellations
 Three common
constellations are:
URSA MAJOR
 Ursa Major (The
Great Bear)
 Ursa Minor (The
Little Bear)
 Orion
ORION
Asterisms
 Asterisms are smaller groups of stars that are
present within constellations. Examples of
these are:
 The Big Dipper (In Ursa Major)
 The Little Dipper (In Ursa Minor)
 Orion’s belt (In Orion)
Movement of the Stars
 Stars in the sky look as if they’re moving from East to
West. This is caused by the Earth’s rotation on its axis.
 If you look south, the stars look like they rise in the east
and set in the west.
 If you look to the north, the stars look like they’re all
spinning (slowly) around one common point. This point
is the North Star (Polaris). The stars “spin” around this
point because the Earth’s axis points directly at Polaris –
this makes it appear stable compared to the other stars.
Axes
 Singular: axis Plural: axes
 Axes are imaginary lines through
a star, planet, moon or other
celestial body that represent the
point at which the planets
revolve. All celestial bodies rotate
on a central axis.
 The Earth’s axis runs from the
North Pole through to the South
Pole. The Earth is actually tilted
in space on it’s axis (the North
pole isn’t the highest part of the
Earth in space). One full rotation
of the Earth takes about 24
hours.
 Jupiter rotates the fastest, taking
only about 10 hours. Venus takes
the longest: about 243 Earth
days.
Orbits and Ellipses
 An orbit is the regular path of a celestial body around another,
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larger celestial body.
In our solar system, the largest celestial body is the Sun. The
Sun follows the same path (orbit) every day. The line that the
Sun’s orbit follows is called the ecliptic. It was named this
because eclipses only happen when the Moon is close to
crossing this line.
The Moon and Planets all follow paths (orbits) that are close to
the ecliptic.
It was originally thought that the Sun, the Moon and all of the
planets followed orbits that were perfect spheres. We have
since learned that the paths they follow are actually ellipses.
Ellipses are oval-shaped. The reason for this is that while the
Sun is large and near the centre of the solar system, the planets
and other celestial bodies also influence the gravitational pull
of each other. This results in the orbits being “stretched out”
and gives the orbits their elliptical shape.
Orbits & Gravity
 Orbits are the result of a perfect balance between the
forward motion (momentum) of a celestial body in space,
such as a planet or moon, and the pull of gravity on it from
another celestial body in space, such as a large planet or
star.
 An object with a lot of mass goes forward and wants to
keep going forward; however, the gravity of another body
in space pulls it in. There is a continuous tug-of-war
between the one object wanting to go forward and away
and the other wanting to pull it in.
 This simulation shows what might happen in the forward
momentum of the Earth or Moon were to change.
Motion of the Planets
 The planets all move at different rates around the
ecliptic. The closer a planet is to the Sun, the faster it
will move around its orbit. Therefore, Mercury will move
the fastest. To remember the order of the planets from
closest to farthest from the Sun, use this phrase:
 My Very Earnest Mother Just Served Us Nine Pizzas
(Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus,
Neptune, Pluto - Dwarf Planet)
 Mercury and Venus are inside the Earth’s orbit around
the Sun, and can only been seen setting just after
sunset or rising just before sunrise. The planets outside
the Earth’s orbit can be seen all night long, depending
on their position relative to the Earth.
Movement of Asteroids and
Comets
 Comets and asteroids are two different things.
Comets are made up of rocks and ice, and their
tails can be seen only when they’re pushed into
the inner solar system (near the Sun). Some
comets have orbits that take them way out to
the edge of our solar system.
 Asteroids are made of rock, and most orbit the
Sun between Mars and Jupiter. Those that can
been seen appear as if they move with the orbits
of Mars and Jupiter.
Theories about the Universe
 Just like with atoms, we know a lot about the
universe because of different theories that
people started developing a long time ago.
 Some of these theories have been completely
discarded, while other have been accepted or
built on.
Aristotle
 Aristotle thought that the universe was geocentric.
This means that he thought the Earth was the centre
of the universe, and that the sun, moon, stars and
other planets revolved around it.
 He based this theory on the fact that he did not see
the patterns of the stars in the sky change, so he
assumed that the Earth was not moving because if it
was the star patterns would also move.
 Aristotle was the first person to suggest that the
Earth was a sphere based on shadows he saw on the
moon during a lunar eclipse. He also proposed that
the fact that the constellations that you can see
change as you go from North to South showed that
the Earth was a sphere.
Aristotle
 Aristotle explained the apparent motion of
celestial bodies by placing all of the celestial
bodies seen from Earth on 22 concentric
spheres. He said that these spheres moved at
different speeds, which caused the different
observations about the movement of the
planets.
Ptolemy
 Aristotle’s model of the universe did not
explain all of the things that people observed.
For example, if you watch Mars every night
for a few weeks and map its position, you’ll
notice that it travels in an ‘S’ pattern. It heads
east, slows down, stops, and then heads west
for weeks.
 Ptolemy watched Mars very closely, and
added to Aristotle’s model of the universe to
explain the way that Mars moved.
Copernicus
 Copernicus lived before the telescope was invented.
He was the first to propose a heliocentric (sun
centric) solar system. Using just his eyes, he
observed that the movements of celestial bodies
that others had noticed could be explained by the
Earth rotating on its axis once a day and orbiting the
Sun once a year.
 Copernicus and others who supported him placed
themselves in danger. Copernicus actually held off
telling people about his theory until he was near
death. Another astronomer, Bruno, who agreed
publicly with Copernicus was burned at the stake.
Galileo
 As we learned last year, Galileo invented one of
the first telescopes. Using his telescope, he was
able to make a lot of observations that no one
could have before, and build on existing theories.
 One important observation was that Venus had
phases, like the Moon. This lent more evidence
to the heliocentric solar system: Venus could not
have phases if it did not orbit the Sun.
 Galileo was put on trial and found guilty of
heresy for publishing his theory. He was put in
prison for the rest of his life.
Questions in Textbook
Answer Questions 1 to 10 on page 375 in your
book, EXCEPT NUMBER SEVEN!!
Use pages 366 to 374 and your notes to help
you.
Kepler
 Kepler worked with a man named Brahe.
They watched the planet Mars for weeks and
tried to work out a model for how it moved.
They found that a spherical orbit didn’t help
to explain Mars’ movement. When they tried
an elliptical orbit, everything fell into place.
 Based on his work, Kepler developed 3 laws of
planetary motion.
Kepler’s Laws of Planetary
Motion
1. All planets move around the Sun in ellipses.
2. When a planet gets closer to the Sun it
speeds up, when it’s further away it slows
down.
3. The time a planet takes to revolve around
the Sun is in direct proportion to how far
away it is from the Sun (i.e. Mercury will
orbit the fastest, Neptune/Pluto the slowest
– depending on which one is considered the
last “planet”).
Newton
 Newton was the first to show that the force of
gravity :
 extends past the surface of the Earth
 affects all celestial bodies, causing them to orbit larger
celestial bodies (moons around planets, planets
around the Sun, etc).
 Newton invented the reflecting telescope (using
mirrors & lenses instead of just lenses).
 This allowed the telescope to be larger in size and give
more exact images.
Astrolabes
 Astrolabes are used to show how the sky
looks at a specific place at a given time. This
is done by drawing the sky on the face of
the astrolabe and marking it so positions in
the sky are easy to find. To use an astrolabe,
you adjust the moveable components to a
specific date and time. Once set, much of
the sky, both visible and invisible, is
represented on the face of the instrument.
This allows a great many astronomical
problems to be solved in a very visual way.
Typical uses of the astrolabe include finding
the time during the day or night, finding the
time of a celestial event such as sunrise or
sunset and as a handy reference of celestial
positions.
 astrolabes.org
Stone Circles
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Stone circles are found all over the
world, although most are in
Europe. Archaeological evidence
indicates that in addition to being
used as places of burial, the
purpose of stone circles was
probably connected to agricultural
events, such as the summer
solstice. Although no one knows
for sure why these structures were
built, many of them are aligned
with the sun and moon, and form
complex prehistoric calendars.
Although we often think of ancient
peoples as being primitive and
uncivilized, clearly some significant
knowledge of astronomy,
engineering, and geometry was
needed to complete these early
observatories.
 http://paganwiccan.about.com/od/
sacredplaces/p/Stone_Circles.htm
In your notebook:
Describe for each planet (p. 400-401):
 Size (Diameter!)
 Shape (Don’t just say a sphere!)
 What it’s made of
 Approx. distance from the Sun (given in AUs – astronomical
unit: 1 AU distance between the Earth and the Sun
 Length of a day
 Length of a year
 Average temperature
 Colour
 Two interesting facts
Use pages 390 to 394 and 402-407
to answer the questions below:
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A thermonuclear reaction is:
How many hydrogen atoms fuse
together in the Sun to form helium?
How long has the Sun been giving
off light?
How much longer will the Sun last?
What is solar radiation?
Solar radiation and what other force
need to be in balance to keep a star
from collapsing?
Describe:
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Sun-spots:
solar flares:
solar prominences :
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What is solar wind?
Why doesn’t solar wind affect us on Earth?
Moons are also called
How did the Earth’s moon form?
What is a dwarf planet?
How many Dwaft Planets are in our solar
system? What are their names?
What is an asteroid?
What is the size range for an asteroid?
What is a comet?
Periodic comets have an orbit of less than
200 years. What is the periodicity of
Halley’s Comet? When was it last visible
from Earth?
What is a meteoroid? How is it different
from a meteorite?
Answer questions 1-14 on page 411 in your
book.
Canada in Space
• Canadians have made several important contributions to space
exploration:
1. The Canadarm: this piece of technology is mounted on the
International Space Station and allows astronauts to sent out
satellites, retrieve them, move large payloads, dock the space
shuttles that arrive at the station, and help astronauts perform
repairs and maintenance on the station.
2. The MOST: this stands for Microvariability and Oscillations of
Stars Telescope. Developed by Canadians, this satellite is about
the size of a suitcase and orbits the Earth in about 100 minutes.
The satellite detects when the light from distant stars is dimmed
slightly, which tells us that a planet has passed in front of it.
These differences are extremely tiny so the equipment on the
MOST must be very sensitive.
How Can We Explore the Universe?
Rocket Propulsion: Rockets transport astronauts and
materials into space. At the beginning of the space program,
animals were sent to make sure that the rockets were safe for
humans. Some animals sent included several types of
monkeys, chimpanzees, dogs and cats (mammals were
preferred because they most resembled people).
Rockets travel by thrust (think of letting go of a balloon that
you’ve almost completely blown up). As the fuel on a rocket
gets used up, parts of the rocket’s propulsion system break off
from the rocket to make it lighter (and therefore require less
fuel).
2. Space Suits: Space suits act as tiny spaceships that provide
oxygen to breathe, temperature control, communication
systems (imagine getting lost on a space walk with no one to
call for help), and pressure control.
1.
• 3. Satellites: these are artificial devices that orbit
the Earth and send information. There are several
types of satellites including communication
satellites, remote sensing satellites, and telescope
satellites like the MOST.
• Satellites can travel in different types of orbits. The
further away the satellite is from the Earth, the
longer it will take to orbit:
– Low Earth Orbit: between 300-500km above the Earth.
These satellites travel around the Earth once every 90
minutes.
– Geosynchronous orbit: satellites placed above the
equator a distance of about 36 000km. These satellites
take about 24 hours to make one orbit. Because they are
rotating at the same rate as the Earth, these satellites
appear to stay in the same place. Communication
satellites are usually placed in geosynchronous orbit.
4. Probes: Probes are unmanned space crafts sent to
other celestial bodies to gather information. They
can fly past, orbit, or land on these bodies. All of the
planets in our solar system have been visited by a
probe, and a recent probe sent to Pluto is set to
arrive in 2015. Probes send images and information
directly back to the Earth.
5. Rovers: Rovers are like the ROVs that we learned
about last year, only designed for outer space rather
than the bottom of the ocean. Rovers have highly
specialized programming so that they can problem
solve and are designed to withstand extreme
temperatures (freezing cold to blistering heat). They
are designed to work all day long and conserve
battery power at night.
6. Optical telescopes : these include both refracting
(lenses only) and reflecting (lenses and mirrors)
telescopes. Large observatories (labs that contain
huge telescopes) are typically built high on
mountaintops above most of the air so that they
are not hindered by atmospheric conditions.
7. Radio telescopes : Radio telescopes collect
wavelengths along the electromagnetic spectrum
that are longer than visible light. Radio telescopes
have large receivers that look like giant satellite
dishes. They convert the radio signals to electric
impulses that are used to discover details about
celestial bodies that you would not be able to find
out with optical telescopes.
Solar Systems, Galaxies and the
Universe
• Solar systems make up galaxies which make up
the universe, just like cities and towns make up
counties/provinces/states which make up
countries which make up the world.
• Solar systems consist of a star and all of the
celestial bodies that orbit around that star.
• Galaxies are made up of several stars, planets,
gas, and dust all held together by gravity.
• The Universe consists of all matter and energy.
The Big Bang Theory
• The theory states that about
13.7 billion years ago, a tiny
volume of space suddenly
and rapidly expanded into a
gigantic size. In a short time,
all matter and energy in the
universe was formed. The
theory was first proposed by
Georges Lemaître in 1927.
The temperature of the Big
Bang was over 1 000 000 000
oC. The universe has been
cooling ever since.
The Oscillating Theory
• Oscillating theory states that not only did the universe
undergo a Big Bang, but that it will also someday undergo
a Big Crunch. The idea is that the universe is closed and
that there is enough matter to eventually stop the
expansion of the universe, and through gravitational
force, reverse it.
• This is in contrast to open universe theories (like the Big
Bang theory) which state that the universe is expanding
and that the rate of expansion is increasing (getting
faster) over time.
Theories about our Solar
System
• There are two main theories about how our solar
system was formed:
1. Stellar Collision Theory: this theory proposes that
the planets and our Sun came from collisions
between stars (like the theory of how the moon
was formed).
2. The Nebular Hypothesis: this theory states that the
Sun and planets were formed when a large nebula
condensed and formed together by gravity. It is
suggested that a nearby star could have exploded
and started the condensing of the nebula. This is
the more accepted theory.
Distances in Space
• We have already learned about astronomical units
(AUs). 1 AU is equal to the distance between the
Earth and the Sun (149 597 870.691 kilometres, or
approximately 150 million).
• Light years are used when distances get up to
millions of AUs. Basically, if you are travelling at the
speed of light, it will take you one year to cross the
distance of one light year. Light travels at about
300 000km/s. One light year is just about 9.5 trillion
(9 500 000 000 000) kilometres.
Major Components of the
Universe
• Nebula: a cloud of gas and dust in
space, where stars are formed.
• Elliptical Galaxies: a galaxy with a
spherical to an elliptical shape that
contains some of the oldest stars
in the universe. Some look like a
baseball, some like a football,
some like a cigar. The largest
galaxies in the universe are
elliptical.
• Spiral Galaxies: Galaxies made
with long arms that spiral out
from each other from a centre
core. The Milky Way is a spiral
galaxy.
Major Components of the
Universe
• High Mass Stars: Stars that have 12 or more times
the mass of the Sun. These stars burn out very
quickly. Become red supergiants and then collapse
into neutron stars or black holes.
• Intermediate Mass Stars: become red giants and
supernova into nebula.
•Low Mass Stars:
become red giants and
shrink into white
dwarves.
Major Components of the
Universe
• Quasars: a region of extremely
high energy that develops as the
supermassive black hole in the
centre of a galaxy attracts more
matter into itself.
• Black Holes: a large sphere of
incredibly tightly packed material
with a huge gravitational pull
created when a star collapses on
itself. Nothing, not even light, can
escape the gravitational field.
Because of this, not one knows
what they look like.
Unit Review
Starting on
page 474,
answer
questions:
 2 to 14
Unit Review
Starting on
page 474,
answer
questions:
 18, 20, 21,
 23 to 25
Unit Review
Starting on
page 474,
answer
questions:
 29, 30, 32, 33,
37,
 39, 40, 43, 45
& 49