Presentation on theme: "1 Understanding the PHYSICS of the Cosmic Times Inquiring into the Nature of the Universe Adapted from Dr. James Lochner USRA & NASA/GSFC Sandra Sweeney,"— Presentation transcript:
1 Understanding the PHYSICS of the Cosmic Times Inquiring 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 Einstein’s four revolutionary theories: E = mc² explains how matter can come from energy, and vice versa (E=energy, m=mass, c=speed of light) Light is not only a wave, but also a particle Theory of Special Relativity: “nothing can go faster than the speed of light” Gravity bends space-time
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
9 New Radio telescope: Earth’s largest steerable radio antenna
10 Telescopes can see all parts of the electromagnetic spectrum Examples of telescope types:
11 Radio telescopes Radio telescopes – capture radio waves The Very Large Array at Socorro,Very Large Array New Mexico, United States – 27 telescopes!!
12 The 64 meter radio telescope at Parkes Observatory - Australia Parkes Observatory
13 Visible light telescopes: reflecting or refracting Refracting
14 Refracting telescopes Advantages Easy to use Excellent for viewing moon, planets, binary stars Sealed tube protects optics and reduces image degrading Rugged, need little or no maintenance 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
15 Famous refracting ‘scopes: Yerkses Observatory (Univ Chicago) Lowell Observatory (Flagstaff AZ) 24” Clark Telescope
16 Reflecting telescope Reflecting telescopesReflecting 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 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) 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
18 Famous Reflecting ‘scopes Hale telescope Mt Wilson CA Keck telescope Mauna Kea, HI
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 universeGeorge Gamow 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
35 Show clip from 1965 CT, with “Murmur of a Bang” and “Big Hiss”
36 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. THE FIRST OBSERVED EVIDENCE OF THE BIG BANG
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.
42 Sco X-1 Scorpius X-1 1 st extrasolar (outside our solar system x ray source) In the constellation Scorpio
43 Taurus XR-1 in the Crab Nebula 1 st 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 = mc 2 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
51 The Universe for Breakfast - Pancake or Oatmeal?? Which describes our Universe best? 1. Pancake: smooth surface but with small differences if you look closely 2. Oatmeal: real “lumps” like galaxies
53 COBE Cosmic Background Explorer COBE took better picture of CMB (Cosmic Microwave Background) Shows some lumpiness that will become galaxies and stars How universe looked 380,000 yrs after BB
54 What is Inflation? Shortly after Big Bang Universe expanded tremendously in very short time Shows how galaxies and stars could be formed from CMB
55 Pulars show evidence of gravitational waves (discovery wins Nobel Prize)
56 Into the Darkness – Dark Matter Matter that gives no visible light – seen with X Rays Dark matter could slow expansion of Universe the distribution of dark matter simulation; dark matter is clustered into halos, connected by filaments
58 Faster Walk on the Dark Side - Dark energy is… a mysterious anti-gravity causing universe expansion to accelerate pushing galaxies apart creating more space Discovered by observations of: visible light, X-ray, radio, and microwaves
60 Sorting Out Dark Stuff Tells what universe is composed of 4% atoms (normal matter) 23% dark matter (tugs on normal matter with gravity) 73% dark energy (flings everything apart)
61 Seeds of Modern Universe WMAP helps see structure of early Universe WMAP: satellite launched after COBE confirms Big Bang Gives better picture of early universe structure Shows more details of what will become galaxies
63 Journey to Cosmos’ Dark Heart Scientists are working to understand dark energy Using new satellites (Joint Dark Energy Mission) to measure distance between galaxies Will tell how fast galaxies have moved away are moving away
64 What is Future of the Universe?? Will Dark energy rip it apart??
65 Will it reach a limit and collapse, and start again??
68 Cosmic Times 1919 - Confirmation of Einstein’s Theory of Gravity 1929 - Hubble’s discovery of Expanding Universe 1955 - Debate between Big Bang and Steady State 1965 - Discovery of the Cosmic Microwave Background 1993 - COBE Results; Development of Inflation Theory 2006 - Grappling with Dark Energy.
69 Cosmic Times: Scientific Themes Our understanding of the Expansion of the Universe Nature of Supernovae The size and scale of the Universe A number of other themes also appear. Impact of improved technology. Role of Women in early astronomy.
70 Unsung Heroes: Women in Early Astronomy Objectives: The students identify and describe unfamiliar scientist “heroes” that contributed to the field of science up to the year 1929. Summary: identify the women scientists of the Harvard College Observatory use the world wide web to complete a product on one of the these unfamiliar scientific “heroes” that they discovered in their research.
71 A print of this Harvard College Observatory photograph was found in an album that had once belonged to Annie Jump Cannon. These women assisted Pickering in measuring stars and features on the photographic plates. Pickering’s Harem
72 Cosmic Times Posters “Newsletter version” for individual student use
73 Cosmic Times Web Site http://cosmictimes.gsfc.nasa.gov/ 1919 & 1929 Posters and Lessons now Available This presentation is available (with links to lessons) 1955 materials available soon. Sign up for email updates
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