Download Space Exploration

Space Exploration
Unit E Overview
The Earth and Space Have Changed
Over Time.
• Tracking cosmological events:
– Winter solstice – December 21
• Shortest day of the year. Beginning of winter.
– Summer solstice – June 21
• Longest day of the year. Beginning of summer.
– Spring equinox – March 21
– Fall equinox – September 22
• Night and day are equal
– Ancient people and natives built structures that
chart these star positions and seasons.
• Models of Planetary Motion
– Geocentric model (Aristotole)
• Earth was believed to be at the center
• Stars were thought to be attached to a celestial sphere
– Heliocentric model (Galileo Galilei/ Copernicus )
• Sun was in the middle of the solar system
• Planets traveled in ellipses instead of circles (Kepler)
• The ideas about planetary motion and star placement
improved as technology improved.
Discovery Through Technology
• Astronomer Tools
– Egyptians used a ‘quadrant’ tool to measure the
height of a star above the horizon. (p378)
– Arabian astronomers used an astrolabe to chart
star positions.
– Levi ben Gurson – invented a cross-staff to
measure the angle between the moon and any
star.
– Telescope (16 C) – showed details of solar system
• The Immensity of Distance and Time (P379)
– Astronomical Units (AU)
• Used for measuring distances w/i our solar system
• A comparison of the distance fr. Earth to the center of the
sun
– (Eg. The sun is 1AU or 149 599 000 km from earth.)
– Light Years
• AU is too small to use outside our solar system
• 1Light year = 300 000km/s x 60s/min x60min/hr x 24hr/day
x 365days/yr or 9.46 x 1015 meters
• The distance that light travels in one year.
• The nearest star, Alpha Centari is 4 light years away
– When we see an object in the sky – it is how it looked
in the past because it took so long for that light to
travel to us.
• Some stars take as long as 25000 years to reach us!!!
• Distribution of Matter in Space
– Stars are giant masses of burning hydrogen,
helium, oxygen, nitrogen, carbon, & silicate dust
– The entire universe has an infinite number of stars
– Stars evolve and change over time and so do their
characteristics
• Birth of a star: star dust (nebulae) starts rotating and
gathering momentum and matierials.
– A protostar is the first stage where hydrogen starts to heat to
10 000 000 C and changes to helium.
– When they become sun-like (massive) they continue rotating
and building for millions and billions of years.
• Life and Death of a Star
– When a star is many billion years old, it begins to use up all its
hydrogen and the helium begins to fuse to carbon.
– The outer layers begin to expand and the star expands and
becomes a RED GIANT (sun-like star) or SUPER GIANT (massive
star).
• Our sun will become a red giant in 5 billion years, extending past the
present orbit of mars!!!
– The final stages begin when the star’s core cool and the
hydrogen-helium reactions stop.
– It becomes a WHITE DWARF (shrunk to the size of the earth)
then a BLACK DWARF.
• It takes so long for a white dwarf to cool that no black dwarf has likely
had time to form in the universe yet.
– SUPER NOVA – the final collapse (massive explosion)
– BLACK HOLE (NEUTRON STAR) – 30 km in diameter
• Has inescapable gravity – not even light can escape
• Star Groups
– CONSTELLATIONS
• Groupings of stars - there are 88 recognized constellations
– ASTERISMS
• Unrecognized star groupings
– Galaxies
• A group of millions / billions of stars, gas, dust
• Held together by gravity
• Shaped like a pinwheel, spiral, ellipse, or irregular
– We live in the Milky Way Galaxy
• It is believed that the MW contains 100-200 billion stars
– Astronomers have estimated that there are a billion-billion
galaxies in the universe!!
Our Solar Neighborhood
• The Sun
– At the centre, 110 times wider than the Earth
– 5500 C on the surface; 15 000 000 C at the core
– Releases charged particles and 400km/hr solar wind
• The Planets (see p 394-5)
– Inner planets: smaller, rocky, closer to sun
– outer (Jovian) planets: large, gaseous, far from sun
• Other Bodies in the Solar System
– Asteroids: rocky, metalic bodies traveling in space
– Comets: dust and ice that travel through space
– Meteors/oids/ites: small rocks traveling at random
• Describing the Position of Objects in Space
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https://lcogt.net/spacebook/using-angles-describe-positions-and-apparent-sizes-objects
– AZIMUTH : the distance shown on a compass (N- S)
– ALTITUDE: the distance from ground level to straight up (0 – 90
degrees)
– ZENITH: the highest point straight overhead
Technological Developments – Space
Exploration - & Human Progress
• Rocket Science
– First ‘rockets’:
• a model pigeon that slid along a wire (400BC)
– – fueled by steam.
• a gun-powder fueled arrow (the Chinese 1AD)
– The Sputnik
• Oct 4, 1957 – Soviet union launched a satellite
• Nov 4, 1957 – Launched a small rocket carrying a dog into space. The dog
survived 7 days.
• Rocket Motion
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Operate using pressure and rushing gasses to propel them
Contain engines, storage tanks, and fins for steering
Fuel: liquid oxygen, gasoline, liquid hydrogen
Payload: crew cabin, food, water, air, people
• New Space Technology
– Ion Drives: use xenon gas instead of fuel
• Electrically charged particles rush out instead of combusting fuel.
• Thrust is 10 000 times weaker than fuel combustion but last a very
long time.
• In space – this is enough to keep motion
– Solar Sails: use the Sun’s light to propel them
• Made of extremely thin material (think plastic wrap)
• Will not run out of energy
– Shuttles - Space Probes – Space Stations
• Transport equipment (such as the Hubble Space Telescope)
• Some orbit earth and allow people to study space from above
– International Space Station
• 16 nations – permanent lab in space
• The same size of three houses.
Surviving In Space
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Studying space from the space station has led to discoveries that will allow people
to live on Mars.
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Environmental Hazards
– No air, no water, comic rays, solar radiation, meteoroids, cold/hot temps that will kill you,
poisonous gasses, air pressure differences
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Psychological Hazards
– Confinement, limited company, distance from home
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Physical Hazards
– Microgravity causes face swelling, legs and arms to weaken, heart to pump less, vision
changes
– Astronauts will need several months to prepare for changes and many weeks to rehabilitate
afterward.
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Chris Hadfield took six weeks before he could walk or drive a car after his last trip
The Suit (see page 421 – figure 2.18)
– Contains air, water a heating and cooling system, a toilet, plus all the tools and technology to
operate machinery.
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Home in Space
– Water and air recycling, micro organism filters, pressure, temp, humidity controls
Space Technology for Earth
• Satellites (Artificial)
– Orbit the Earth, loaded with digital and electronic equipment.
– Help us to communicate, observe, forcast weather, predict magnetic storms,
find our location (GPS), watch television, make long-distance calls, find nearby
businesses………
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Communication satellites
Research satellites
Remote sensing satellites
Personal tracking satellites
• Space-Age materials for Earthlings
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Computer technology
Consumer technology (food!)
Medical and health technology
Industrial technology
Transportation technology
Public safety technology
• See page 431 for a list of the inventions that we use in our daily life designed for space!
Radio Telescopes, Optical Telescopes
and other Technologies
• Optical Telescopes
• First used 400 yrs ago
• Gather and focus light from stars so we can see them
• Refracting Telescopes: use two lenses to gather light
– Limited in size and strength
• Reflecting Telescopes: use mirrors instead of lenses
- gather and focus light from stars
- Use metal or spun glass to reflect light onto lens
- Segmented mirrors have greater light gathering ability
- Interferometry : combining telescopes
- Using two or more telescopes to get greater power
- The Hubble Space Telescope
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Works in space away from light, pollution, weather
600 km above Earth
13 x 4.3 meters
Has detected light from stars that has taken 12 billion years to reach
Earth
Using Technology to Detect Space
• Measuring Distance (page 447 – figure 3.2)
– Triangulation: measuring angles using geometry
• Measure a baseline (on the ground)
• Use a protractor to measure the angles between the baseline and
your target
• Use a scale model of the drawing and convert it to actual distance.
– Parallax: the apparent shift in position when viewed from
different positions
• Eg. When you have an object that you view from your right eye,
then your left eye. It appears to have moved but really, the
viewing angle is just slightly different.
• Astronomers use a star’s parallax (angles) to triangulate the star’s
distance from earth
• Measurements of stars can be taken months apart to create a
wide enough base.
• Determining a Star’s Composition
– Each star has its own color fingerprint
– Different elements absorb light in different ways
– The % of an element (helium, hydrogen, carbon)
will give a star its own unique appearance.
– Astronomers use a SPECTROSCOPE to determine
the composition of a star based on color.
• Determining a Star’s Direction of Motion
– Astronomers use the DOPPLER EFFECT to measure
how light waves far are moving
• The closer they are, the brighter the star…
• Blue and red shift indicate how close a star is
Space, Society and the Environment
• Risks and Dangers of Space Travel
– Weather, malfunctioning equipment, birds, floating debris, meteroids,
cosmic radiation
• Space junk: all the stuff that has fallen off of rockets
• Even small washers, screws, micrometeorites can be dangerous at 20 000km/h
• Some space junk (old satellites) will fall to earth and cause radiation hazards
• Canadian Contributions to Space
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The Canadarm – robotic arm for the shuttle/ Hubble
Alouette 1 – first non-military satellite
Anik 1 – first telecommunications satellite
See page 463 for Canadian Astronauts
• Political – Ethical – Environmental Issues
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Who owns space? Who will use its resources?
Is it right to spend money in space rather than on Earthly problems?
Who will protect space environment? Clean up space junk?
Who will determine how space is used?