Understanding the PHYSICS of the Cosmic Times Inquiring into the Nature of the Universe

1. Understanding the PHYSICS of the Cosmic TimesInquiring into the Nature of the Universe Adapted from Dr. James Lochner USRA & NASA/GSFC Sandra Sweeney, Joseph Petsko Perkiomen Valley School District, PA

2. Understanding the PHYSICS of the Cosmic Times 1955

3. The world mourns Einstein’s Death

5. Big idea inYardsticks:The universe is twice as big as thought : Two Types of Cepheids! • During the wartime blackouts in California, Walter Baade used 200” Hale telescope and discovered two different populations of stars in Andromeda • There are two types of Cepheids, with two different period-luminosity relationships. • Hubble had unknowingly used the wrong relationship. • Like measuring with a Yardstick when he should have used a Meterstick

6. A new type of star discovered: the supernova • Giant exploding stars • Create heavier, bigger elements • Elements discovered by use of spectroscopy

8. Star life cycle: see textbook

9. New Radio telescope: Earth’s largest steerable radio antenna

10. Telescopes can see all parts of the electromagnetic spectrumExamples of telescope types:

11. Radio telescopes – capture radio waves • The Very Large Array at Socorro, • New Mexico, United States – 27 telescopes!!

12. The 64 meter radio telescope at Parkes Observatory - Australia

13. Visible light telescopes: reflecting or refracting Refracting

14. Refracting telescopes Advantages Disadvantages Generally small apertures, 3 to 5 inches Tough to see small and faint deep sky objects (distant galaxies and nebulae) Heavy, long and bulky Can be expensive per inch of aperture • Easy to use • Excellent for viewing moon, planets, binary stars • Sealed tube protects optics and reduces image degrading • Rugged, need little or no maintenance

15. Famous refracting ‘scopes: • Yerkses Observatory (Univ Chicago) • Lowell Observatory (Flagstaff AZ) • 24” Clark Telescope

16. Reflecting telescope Reflecting telescopes use a huge concave parabolic mirror instead of a lens to gather and focus the light to a flat secondary mirror that in turn reflects the image out of an opening at the side of the main tube. You look through an eyepiece on the side of the tube up near the top.

17. Reflecting telescopes Advantages Disadvantages Not suited for terrestrial applications Some light loss when compared with refractors Dust can get onto optics due to open tube even if kept under wraps May require more care and maintenance • Easy to use and construct • Excellent for faint deep sky objects (galaxies, nebulae and star clusters) • Few optical irregularities, deliver very bright images • Reasonably compact and portable • Costs less per inch of aperture compared to refractors (mirrors cheaper than lenses)

18. Famous Reflecting ‘scopes Hale telescope Mt Wilson CA Keck telescope Mauna Kea, HI

20. Hubble space telescope

22. 2 different theories of the universe’s origin: • Steady State Theory: As universe expands, matter is created; may appear unchanging • Universe is eternal, stars always being made • Evolutionary Theory (a.k.a. the Big Bang theory): running expansion backwards leads us to a point of high density and high temperature from which universe originated. (created everything all at once) • 2 possible outcomes: • All will suck back together due to gravity and rebound, back and forth forever OR • Everything expands forever

23. Steady State Universe Fred Hoyle, Hermann Bondi and Thomas Gold see the movie The Dead of Night, in which the end of the story circles back to its beginning. • Unchanging situations need not be static • New matter can be created spontaneously as the universe expands (a few hundred atoms per year per galaxy) • Expansion of universe and creation of new matter balanced via a negative energy. • The universe is constant in its overall density

24. Evolutionary Universe Starting from earlier work, George Gamow & Ralph Alpher worked out the conditions in the early universe • Universe is expanding from a state of high density and pressure. • Hydrogen & Helium were formed as universe cooled. • There should be left over a background radiation with a temperature of ~ 5 Kelvin Hoyle scoffed at this theory and coined the term “Big Bang”

25. What is the Evidence? • The Mark 1 radio antenna constructed to detect radio waves leftover from the Big Bang

26. Spectroscopy • What is spectroscopy? • The study of light • Most objects in space give off visible light • This light is captured and analyzed with spectroscopes

27. Spectroscopy – the study of light

28. Purpose of spectroscopy:See the element’s “fingerprint” coming from star or galaxy

29. Using a spectroscope, astronomers can detect the elements in a star – can know its life stage, temperature, movement,…

30. Light Source Colors that you see

31. Try the spectroscope activities…

32. Use the known element’s spectrum to identify the unknown elements

33. Recording data from a spectroscope

34. 1965

35. Show clip from 1965 CT, with “Murmur of a Bang” and “Big Hiss”

36. THE FIRST OBSERVED EVIDENCE OF THE BIG BANG Tool used: • Penzias and Wilson were using a 20-foot horn detector to test satellite communication. • Effort to reduce fuzz/hiss in the detector left them with a 3 K residual. But they didn’t know its origin.

37. Tool for Determining “Steady State” vs. “Big Bang” • Peebles and Dicke (Princeton) had just calculated an estimate for the temperature (3.5º K) of the residual background radiation from the big bang explosion, and found it was detectable in the microwave region. • Called “cosmic background radiation” • Peebles and Dicke were convinced that Penzias and Wilson had found it. This was strong evidence against the Steady State model of the universe and for the Big Bang theory.

38. Review of…

39. Supernovae Leave Behind X Rays • X rays in space detected with “sounding rockets” • Atmosphere blocks harmful X-rays • Good for us that it does ”

40. Why do we need telescopes in space?

41. Absorption of electromagnetic radiation

42. Sco X-1 Scorpius X-1 • 1st extrasolar (outside our solar system x ray source) • In the constellation Scorpio

43. Taurus XR-1 in the Crab Nebula • 1st X Ray source in constellation Taurus

44. Ophiuchus XR-1 • Found in constellation Ophiuchus (serpent bearer) • Kepler’s supernova from 1604 • In foot of Ophiuchus

45. New Problem #1, assuming the Big Bang to be true: • Will the universe eventually collapse back into itself, and explode again in an endless cycle (“oscillating universe”) OR • Will the universe keep increasing in size forever with each galaxy isolated in emptiness?

46. Problem #2 has arisen with improved technological observations Galaxies do not appear to have enough mass in them compared to their energy or luminosity (brightness). Most of the galaxy’s mass is not giving off light. E = mc2 The massive amounts of energy (brightness) must come from some great amount of matter!! How could 99% of the mass be MISSING!

47. Problem #3 • X-rays are being detected from the universe… But from where?

48. Discovery of QUASARS • Galaxy-like objects that emit radiation that we can detect • Power of 10 trillion suns • Travel at 450 million miles/hr. (2/3 speed of light) • They have been detected nearly 14 billion light-years away. What does this distance tell us about the age of the universe?

49. Approaching the Present Cosmic Times 1993 and 2006