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Paths to Discovery in Radio Astronomy

Explore the history of radio astronomy, from Galileo's first telescope to the modern Square Kilometre Array (SKA), and learn about key discoveries along the way. Discover the mysteries of the universe, including dark matter and dark energy. Find out how the SKA project is revolutionizing our understanding of the cosmos.

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Paths to Discovery in Radio Astronomy

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  1. Paths to Discovery in Radio Astronomy WARS2006 Ron Ekers CSIRO Leura 16 Feb 2006

  2. Galileo Galilei - 1609 • Galileo builds his first telescope and he sees the moons of Jupiter. “Four planets, never seen since the beginning of the World right up to our day”

  3. More than 300 years later • Mankind had its next new view of the Universe • The discovery of a new kind of telescope opens a new window on the Universe using radio waves

  4. Karl Jansky Bell Telephone Laboratory 1932

  5. Jansky’s Cosmic Hiss Unexpected source of noise peaking each day signal arrives 4 min earlier each day reaction from Bell Labs “so faint not even interesting as a source of radio interference!” not accepted by the astronomical community at the time no theoretical framework Beginning of Radio Astronomy

  6. Science Fiction • Dec 1938 • Edmond Hamilton • The Cosmic Hiss • Based on Jansky’s observation of cosmic hiss • Extra Terrestrial Intelligence? R D Ekers

  7. Grote Reber’s Challenge • In 1933 Karl Jansky reported the discovery of radio emission from the centre of the Galaxy • Grote Reber was a 22 year old engineering graduate specializing in electronics and communication professional astronomers showed little interest so I consulted with myself and built a dish R D Ekers

  8. The Ascendance of Low Frequency Radio Astronomy • 1937 Wheaton, Illinois. Built a 32’ parabolic dish • 1939 detected cosmic static by going to longer wavelengths • 3300 MHz • 900 MHz • 160 MHz • Had to be non-thermal • 1950 Synchrotron radiation • First radio map of sky • Great difficulty getting published R D Ekers

  9. Sydney, Australia 1948 Cliff Interferometer • Cliff interferometer CSIRO, Australia (1948) • Built to identify the radio stars (John Bolton) • Idea from multiple path interference in ship borne radar • Discovery of extragalactic radio sources at great distances • Centaurus A , Virgo A, Cygnus A, Fornax A • Had to hedge on extragalactic origin to get paper published

  10. Cliff interferometer • Bolton, Stanley and Slee • 100MHz Yagi R D Ekers

  11. Centaurus A

  12. Discovery of Quasars (1963) • The Lunar Occultation of 3C273 • CSIRO’s Parkes Observatory identifies a strong radio source with a bright star • A few of these weird stars already known • variable light so “couldn’t be extragalactic” • Schmidt interprets the spectrum as due to huge redshift • Flash of insight - Schmidt's thumb • Observational Cosmology is born • Gravitational Collapse and Relativistic Astrophysics • Dallas, Texas 1963 • only a black hole could provide the energy

  13. Black Holes

  14. Bell Telephone Laboratories 1965 • Nobel prize to Penzias and Wilson for discovery of the Big Bang radiation • Bob Dicke’s experiment to search for this was already in progress • Penzias & Wilson did not know about the Dicke exoperiment • ironically Dicke had missed the earlier (1948) prediction of Gamov. • Technology driven serendipity

  15. COBEThe microwave background

  16. WMAPStructure in the Big Bang Radiation

  17. Discoveries • Pasteur In the field of observation, chance favors only the prepared mind • Horace Walpole (1754) As the three princes of Serendip traveled, they were always making discoveries, by accidents and sagacity, of things they were not in quest of.

  18. Serendipity in Science • Pasteur – immunization • Roentgen - Xrays • Fleming – penicillin • Huygens – polarization • Oersted – electromagnetism • Muller - DDT • Crick and Watson – DNA (more later)

  19. What more is there to know Radio Image of Ionised Hydrogen in Cyg X CGPS (Penticton)

  20. The Universe

  21. The Universe Dark Mater – Dark Energy • Big Questions • Dark matter? • Dark energy?

  22. WMAPStructure in the Big Bang Radiation

  23. CMB temperature power spectrum (WMAP)

  24. Dark energy oscillations change scale with time Very large Collecting Area Very large Field of View TIME

  25. How do we find out? • We need a Square Kilometre Array ! R D Ekers

  26. Reference Design R D Ekers

  27. Multibeam Dishes or Multiple Dish Arrays $$$ (Steel) $$$ (computers) Computer Computer Structural/signal processing cost R D Ekers

  28. Site selection • Physical characteristics required • Very quiet radio frequency environment, particularly for the core region • Large physical extent (>3000 km) • Low ionospheric turbulence • Low troposphere turbulence R D Ekers

  29. Site selection - RFI Sydney: population 4 million Narrabri: population 4000 Mileura: population 4

  30. Ken LynnIonospheric Systems Research R D Ekers

  31. SKA timeline Inter-governmental discussions including site selection ‘1% SKA’ Science Initial concept ‘10% SKA’ Science First SKA Working Group ISSC MoAs Science Case published Site ranking SKA Complete { { { 92 96 20000405 06 07 08 09 1014 18 22 2000 { 2000 { { { Feasibility study Concept exposition Optimise Design Define SKA System Phase 1 Build 10% SKA Full array Build 100% SKA SKA can be built in stages

  32. ALMA from Little Scienceto Big Science • De Solla Price (1963): most scientific advances follow laboratory experiments • exponential growth in capability occurs in all successful science • Little science, big Science Individual researcher ↓ Institute laboratory ↓ National Facility ↓ International Facility

  33. SKA ATA Phoenix Enhanced SETI Searching

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