Space Exploration

1. Space Exploration Unit E Overview

2. 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.

3. 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.

4. 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 benGurson – invented a cross-staff to measure the angle between the moon and any star. • Telescope (16 C) – showed details of solar system

5. 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!!!

6. 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.

7. 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

8. 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!!

9. 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

10. Describing the Position of Objects in Space • 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

11. 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 • 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

12. 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.

13. Surviving In Space • Studying space from the space station has led to discoveries that will allow people to live on Mars. • Environmental Hazards • No air, no water, comic rays, solar radiation, meteoroids, cold/hot temps that will kill you, poisonous gasses, air pressure differences • Psychological Hazards • Confinement, limited company, distance from home • 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. • 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. • Home in Space • Water and air recycling, micro organism filters, pressure, temp, humidity controls

14. 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……… • Communication satellites • Research satellites • Remote sensing satellites • Personal tracking satellites • Space-Age materials for Earthlings • 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!

15. 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 • 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

16. 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.

17. 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

18. 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 • 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 • 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?