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Our Place in Space

Our Place in Space. Earth : (small) 15 thousand km (12,000 miles) in diameter Sun : 15 million km in diameter Solar System : about 6 billion km in diameter. Our Place in Space. Milky Way Galaxy - 1000 quadrillion km or 100,000 light years in diameter

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Our Place in Space

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  1. Our Place in Space • Earth: (small) 15 thousand km (12,000 miles) in diameter • Sun: 15 million km in diameter • Solar System: about 6 billion km in diameter

  2. Our Place in Space • Milky Way Galaxy- 1000 quadrillion km or 100,000 light years in diameter • It would take a beam of light 100,000 years to cross the entire galaxy!

  3. The Milky Way Galaxy

  4. Hubble Space Telescope (HST) Deep-Field Camera Photo – Every Dot or “Smudge” is a Galaxy!

  5. Constellations • Patterns of stars in the night sky • Named after mythological beings, heroes or animals • 88 constellations (mostly Greek) are recognized in the Western world • Different cultures grouped stars differently

  6. Constellations • Ecliptic – plane in which the Sun & planets travel • Zodiac – 12 major constellations in the ecliptic

  7. Constellations • Astrology (not a science) uses relative positions of stars and planets to attempt to predict the future • Astronomy & astrology were once the same in the distant past

  8. Polaris is Part of a Triple-Star System – Artist Concept

  9. Stars They are other Suns

  10. Many different type • Stellar classification • Most stars are currently classified using the letters O, B, A, F, G, K, and M, where O stars are the hottest and the letter sequence indicates successively cooler stars up to the coolest M class.  • Quick quiz • Arrange in order from hottest to coolest • A, B, F, G, K • O, M, A • B, A, K,O, M

  11. Here they are

  12. Are stars on fire?! • Dr. Feynman • Oooooook, so are stars on fire Mr. McCormick? • Not exactly. • Stars turn mass into energy. They really don’t burn anything. • Stars turn mass into energy • E = mc2

  13. They do this!

  14. All stars do this • Every star, no matter how large or small, no matter where they are; every star starts its life with the proton-proton chain • Failed stars and so called dark objects, objects that might have become stars if given enough mass, never start the p-p chain. • Lets make sure we understand this fully. • Take out a piece of paper and draw, IN GOOD DETAIL, the p-p chain

  15. Buzz words • Stars produce light, we can see them. • Go out tonight and look up at the stars, they are very beautiful. • About 99% of our solar system’s mass is tied up in the star. • Planets, comets, gas giants, etc… • So when we look at a galaxy we only see stars and they make up about 99% of the solar system they create.

  16. Buzz words cont • So only about 1% of a galaxy should be “dark matter”, stuff that doesn’t make light • Comets, planets, asteroids, and gas giants. • However, most of the mass in a galaxy is made up of dark matter………so you know…..that's a problem.

  17. Bayer designation • A Bayer designation is a stellar designation in which a specific star is identified by aGreek letter, followed by the genitive form of its parent constellation's Latin name

  18. example

  19. We will learn these symbols. • I think its neat • It’s a dying language • It’s the language of the discipline of science we are coving • I think its neat

  20. Astronomy

  21. Two words, two ideas • Astronomy – The study of the stars. • Size • Temperature • Life cycle • Movement • Content • etc • Cosmology – the study of the universe • Content • Time frame • Size • Speed • Open, closed, expanding • etc

  22. What do stars produce? • Radiation - radio waves • 10^3 – 10^9 • Microwaves* • 10^10 – 10^11 • Infrared • 10^12 – 10^14 • Visible light • ~10^14-10^15 • Ultraviolet • 10^15 – 10^17 • X ray • 10^17 – 10^19 • Gamma • 10^20 – 10^23 • Particles • Before death • He to Fe • At death • Fe to Cn • Before and during • Neutrinos • Cosmic rays • Beta and alpha particles • Pretty much the entire particle zoo • Death • Depends on the state.

  23. How to capture Radiation • CCD (Charge Couple Device) – cannot store digitally • Optical telescopes • Pages 44-46 chapter 2 • Infrared • Ultraviolet • X ray • Gamma ray • Before CCD you used glass plates with sliver nitrate and exposed to light. • Radio telescopes • Page 47 • Store signals digitally • Computer • Many types of software do this. • Mainly found in commercial radio stations. • **side note • Super easy to create a large array of radio dishes to collect tons of data. • HOWEVER, not the “good” type of data.

  24. Early missions • Rockets - Two types • Liquid vs solid • Read and know the difference • Best way to get out of the earth’s atmosphere • Satellites started space race

  25. So lets act like baby astronomers • Wien’s Displacement Law • λmax T = .290 cm K • Where λmax is the maximum wavelength produced by the star • T is the temperature of the star • Primarily used by photometry related astronomers.

  26. There is a relationship between wavelength and temperature

  27. Example problems • We observe a star with surface temperature of ~ 3400 K. • What is its peak wavelength? • What type of star is it? • We observe a star with peak wavelength of 4.53 X 10^-4 cm • What type of wavelength of light does it produce? • How hot is the star?

  28. wavelengths • Transverse • How light travels • Wave travels 90degrees perpendicular to direction of displacement • Longitudinal • How sound travels • Wave travels in the SAME direction of displacement

  29. Longitudinal

  30. Transverse

  31. Wave, particle, why not both? • Light acts as both a wave and a particle • Particles with low mass also act as both a wave and a particle • The more mass, the less wave-like qualities an object has. • DeBroglieWavelength

  32. Exo planets • Extra solar planets • Exo planets for short • Planets outside our solar system • 25 direct images • Pictures • 707 photometry or radio velocities • Some 3600 Keplercandidates • . Over 4000 total

  33. Photometry detection

  34. Real data!!

  35. How cool is this?!

  36. KNOW THIS PROBLEM FOR THE TEST • Some star with radius, r = 12, has a planet that orbits it ever 3 days. If you happen to observe this star for 12 days you will see a transit event. Your CCD detects 100 photons BEFORE the transit and only 80 photons DURING transit. • What percentage of the star is covered by the planet? • 8th grade only: what is the radius of the planet?

  37. solution • 1st – find the percentage difference in the amount of photons, BEFORE – DURING. • 100 -80 = 20 • So 20% or .20 of the photons are lost due to transit • 2nd – using the surface area formula solve for the surface area of the star. • 3.14 X 12 X 12 (or 12^2) = 452 • 3rd – multiply area of star by % lost to get the area of the planet. • 452 X .20 = 90 • 8th grade cont to next slide

  38. 8th grade cont • Having solved the area of the planet, 90, plug that back into the area formula, this time solving for r. r = square root (area/3.14) • Your answer should be 5.3

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