Science 9

1. Science 9 Aim: Development of Technology, and Star Cycles.

2. Agenda • Homework Questions Due • Continuation of Space Notes

3. The Life of a Star Eventually the star’s fuel runs out. When the hydrogen in the core has been used up, the stable-state star shrinks in size.

4. The Life of a Star Nuclear reactions occur, leading to the expansion of the outer layer In these terms, stars become larger, turning into a Red Giant (if it is “Sun-Like”) or a Red Supergiant (if it is Massive)

5. The Life of a Star Note: Our sun won’t become a Red Giant for approx. 5 Billion years, when the diameter may extend past Mars’ current orbit

6. The Death of a “Sun-Like” Star Fusion ends when the temperature is no longer hot enough to keep the reaction going … the star continues to shrink and becomes a White Dwarf (no bigger than earth)

7. The Death of a “Sun-Like” Star The star continues to shrink until it becomes a cold, dark Black Dwarf (this process takes so long, it is unclear if a Black Dwarf has yet to be formed)

8. The Death of a “Massive” Star Gravity causes the star’s core to collapse rapidly on itself… … this collapse ends suddenly with an outgoing shock wave and massive explosion, called a Supernova

9. The Death of a “Massive” Star After the Supernova, only the a small core is left, called a “Neutron Star” or “Black Hole”

10. The Death of a “Massive” Star “Black Hole” = highly dense remnant of a star in which the gravity is so strong, not even its radiant light can escape

11. The Death of a “Massive” Star Astronomers only know about their existence indirectly because of how material near a black hole becomes very hot and bright

12. Our Solar Neighbourhood

13. The planet Earth orbits a star that is one of billions of stars in a spiral galaxy called the Milky Way…

14. Formation of a New Solar System • A cloud of gas and dust in space begins swirling • Approx. 90% of this material accumulates in the center, forming the Sun • Remaining 10% accumulates in smaller clumps and orbits the sun (i.e.. planets)

15. Stars • Billions of billions in our universe • Fall into Several Distinct Groupings  White Dwarfs, Main Sequence, Giants, & Supergiants(will discuss these later) • The most important star to us on Earth? … The Sun

16. The Sun • Is an “ordinary” star at the center of our Solar Neighbourhood • Composed of hydrogen and helium • Largest object in the solar system • 110 times the diameter of the Earth • The sun’s surface temperature is 5500Oc

17. solar wind “Solar Wind” Stream of charged particles flowing from the Sun out into space Earth’s magnetic field protects us from the solar wind

18. Solar Flares Sun ejects bursts of high energy particles that can have dramatic effects on the Earth ranging from power line surges to radio interference to the aurora borealis (the Northern Lights)

19. Solar Flares Sun ejects bursts of high energy particles that can have dramatic effects on the Earth ranging from power line surges to radio interference to the aurora borealis (the Northern Lights)

20. Solar Eclipse • Occurs when the Moon passes between the Sun and the Earth, casting a shadow on Earth • most are partial eclipses where the Sun is only partially obscured

21. The Planets in our Galaxy • Video

22. The Planets Inner Outer Jovian Gas giants Jupiter, Saturn, Uranus, Neptune composed of gases (H & He) low density deep atmosphere fast rotation rings lots of satellites (moons) • Terrestrial • Rocky (Earth-like) • Mercury, Venus, Earth, Mars • composed of rock & metal • relatively high density • solid surfaces • slow rotation • no rings • few satellites (moons)

23. Other Objects in Space • Asteroids– small, rocky bodies orbiting the Sun and lying mainly in a narrow belt between Mars and Jupiter • Comets– a celestial body composed of dust and ice (“dirty snowball”) that orbits the Sun; it has a bright centre, and long faint tail that always points away from the Sun

24. Meteoroid– a solid body, usually a fragment of rock or metal, travelling in space with no particular path • Meteor– a meteoroid that enters Earth’s atmosphere, where the heat of friction causes it to glow brightly (“shooting star”) • Meteorite– the remains of a meteor that reaches Earth’s surface; a fallen meteoroid

25. Describing the Position of Objects in Space

26. To locate an object in space, two questions must be answered: • How high in the sky is it? • In what direction?

27. A star’s position when viewed from a particular point, can be determined by: • The compass direction (“Azimuth”)  Due north is 0o  Going clockwise & measured in degrees 2) The altitude how high in the sky  ranges from 0o (at the horizon) and 90o(straight up)

28. Zenith = refers to the highest point directly overhead

29. Astrolabes Astrolabes have been used for centuries to determine the position of celestial bodies. Two coordinates must be given: Azimuth – 360o (N, E, S, W) Altitude – 0o to 90o

30. Movement of the Stars Stars appear to stay in one place, but when viewed night-after-night for a long time, some stars seem to move slightly

31. Observing Planetary Motion After a few days or weeks, one notices planets moving in relation to a background of stars “Planet” – Greek for Wanderer

32. The path in the sky along which the Sun appears to move is called the ECLIPTIC

33. CELESTIAL EQUATOR = The imaginary line around that sphere of sky directly above the Earth’s Equator

34. SPACE EXPLORATION GETTING TO SPACE

35. Getting to Space First Problem…  How do we overcome the force of gravity?

36. Getting to Space First Problem…  How do we overcome the force of gravity? Need an object to move at a minimum speed of 28 000 km/hr to overcome gravity and leave our atmosphere

37. Getting to Space Second Problem…  How do we get off the ground carefully with such high speeds?

38. Getting to Space Second Problem…  How do we get off the ground carefully with such high speeds? Rockets!!

39. History of the Rocket: 400 B.C.  Greek Mathematician Archytas used escaping steam to propel a model pigeon along a wire Note: Not Actually Archytas’ rocket 

40. History of the Rocket: 400 B.C.  Greek Mathematician Archytas used escaping steam to propel a model pigeon along a wire ~100 A.D.  The Chinese used gunpowder to make rocket-propelled arrows for the battle

41. History of the Rocket: 400 B.C.  Greek Mathematician Archytas used escaping steam to propel a model pigeon along a wire ~100 A.D.  The Chinese used gunpowder to make rocket-propelled arrows for the battle 1957  The Soviet Union launches the first satellite, called Sputnik

42. The Science of Rocketry … is based on the fundamental law of physics, that states: For Every Action, there is an Equal and Opposite Reaction Example of a Simple Rocket:

43. The Science of Rocketry … is based on the fundamental law of physics, that states: For Every Action, there is an Equal and Opposite Reaction Rockets use gas under pressure confined in a chamber or tank. Opening the chamber allows gas to be released, producing a thrust

44. The Science of Rocketry … is based on the fundamental law of physics, that states: For Every Action, there is an Equal and Opposite Reaction Rockets use gas under pressure confined in a chamber or tank. Opening the chamber allows gas to be released, producing a thrust

45. The Science of Rocketry … is based on the fundamental law of physics, that states: For Every Action, there is an Equal and Opposite Reaction Rockets use gas under pressure confined in a chamber or tank. Opening the chamber allows gas to be released, producing a thrust, and causing the rocket to be propelled in the opposite direction

46. Parts of a Rocket 3) Payload  Material needed for flight j(crew cabin, food, water, air,people, etc) • Structural Elements:  Exterior Structure, Storage Tanks, Fins • Fuel Liquid Oxygen or Gas or Liquid Hydrogen

47. Future of Rocketry Ideas Include:  Ion Drives  Solar Sails

48. Future of Rocketry Ion Drives = use xenon gas (instead of chemical fuels) is electrically charged, accelerated and then emitted as exhaust = the thrust force is 10,000 times weaker than today’s rockets but lasts much longer little force + long time = very fast vehicle

49. Future of Rocketry Solar Sails = when the sun’s energy hits carbon fibre sails, the energy transfer causes the spacecraft to move Could Potentially be in use by 2015