By Annie Kelley,2014-12-12 00:33
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7. Physics News off the Web compiled by John O’Connor, Past Federal

    President of AIP Highlights:

    ; Large galaxies formed surprisingly early

    ; Large scale structures in the early universe

    ; Double pulsar find to test relativity

    ; Rainbows

    ; The special effects (SFX) of physics


    You'd expect that a census of the farthest, earliest galaxies would feature a lot of smaller, hotter, younger, bluer galaxies, perhaps in the act of smashing into and coalescing with their neighbours. But a new survey made using the 8-metre Hawaii telescope of the Gemini Observatory shows rather that at only a comparatively short time after the big bang the universe was already well furnished with large, reddish, mature elliptical galaxies. The Gemini Deep Deep Survey (GDDS) trawled the poorly patrolled "Redshift Desert" region of cosmic history, the epoch roughly 3 to 6 billion years since the big bang and found instead what team member Roberto

    plenty of massive old Abraham (University of Toronto) calls a "Redshift Dessert"---

    galaxies where you'd expect few. Abraham and his colleagues reported the results at this week's meeting of the American Astronomical Society (AAS) in Atlanta. Patrick McCarthy (Carnegie Institution) said that what the survey shows is that at a point only 4 billion years into the life of the universe there were already galaxies up to 3 billion years old. This leaves very little time for the assembly of something as big as an elliptical galaxy. Furthermore, the galaxies in the survey possess a plentiful stock of heavier "metal" atoms, the kind that would have to be cooked up in repeated cycles of star birth and supernova. To put the question in term of galaxy demographics: how could there be so many senior citizens so early? According to Roberto Abraham, all of this should make theorists sweat. (


    expected. Like the presence of surprisingly early mature galaxies at a redshift of about 2 (see the item above) another result at the AAS meeting suggests that the standard cosmological model---or at least that part of it devoted to galaxy formation---is in need of revision. A group of astronomers using the Blanco Telescope of the Inter-American Observatory in Chile and the Anglo-Australian Telescope in Australia reported seeing a grouping of 37 galaxies, all at a redshift close to 2.38, spread 300 million light years across the sky. Povilas Palunas (University of Texas) said that this constitutes the largest observed structure in the distant universe. According to models that simulate how the hot diffuse matter of the infant cosmos distilled into a web of knots and filaments, such an immense agglomeration should not have arisen so quickly. The statistical case for saying that this sampling of bright galaxies (fainter galaxies could not be seen) is truly a coherent structure and not just a chance juxtaposition can be expressed as a probability with 1000-to-1 odds, a likelihood obtained by looking not at the specific arrangement of galaxies themselves but at the daunting amount of void between the galaxies. Gerard Williger (Johns Hopkins) said that he and his colleagues would naturally like next to sample adjoining volumes of deep space in order to test the proposition that the hasty filamentation of matter seen in this initial data set (the observed galaxies lie in the southern constellation "Grus") is not an isolated incident (

Double pulsar find to test relativity

    An international team of scientists working in the UK, Australia, Italy and the USA has made an astronomical discovery that has major implications for testing Einstein's general theory of relativity. Using the 64-m CSIRO Parkes radio telescope in New South Wales, Australia, the team recently detected the first system of two pulsars orbiting each other - the only system of its kind found so far among the 1400-plus pulsars discovered in the last 35 years. Read more at:

Physics World Light fantastic (Feb 4) One of the reasons why rainbows are so

    special, as Robert Crease writes on page 16, is that they are rare, but not so rare that people are not familiar with them. Most readers of this magazine will have some inkling of how a rainbow is formed, but could you, if pushed to the test, derive what happens from first principles? And what about ice-crystal haloes, fog-bows and glories? Those who need to refresh their memory about any of these beautiful natural optical phenomena should turn to John Hardwick's article in "The subtlety of rainbows".

Physics World The subtlety of rainbows (Feb 4) Subtle physics is needed to explain many

    of nature's mysterious atmospheric optical phenomena, including rainbows, ice-crystal haloes and the much rarer fog-bows, dew-bows and glories

Physics World Natural photonics (Feb 4)

     Optical tricks that have given butterflies, beetles and other creatures an evolutionary advantage are beginning to teach physicists a thing or two about advanced photonics

     Physics World The special effect of physics (Feb 4) From Hollywood blockbusters to the

    design of aircraft cockpits, the visual-effects industry relies on tracing the path of light to create scenes that do not and may never exist

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