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Mysterious Objects at the Edge of the Electromagnetic Spectrum

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  • derhexer@aol.com
    URL to an article from NASA _http://science.nasa.gov/science-news/science-at-nasa/2012/16mar_theedge/_
    Message 1 of 1 , Mar 16, 2012
      URL to an article from NASA

      This is a wonderful time to be alive

      First few paragraphs
      "March 16, 2012: The human eye is crucial to astronomy. Without the
      ability to see, the luminous universe of stars, planets and galaxies would be
      closed to us, unknown forever. Nevertheless, astronomers cannot shake their
      fascination with the invisible.

      Outside the realm of human vision is an entire electromagnetic spectrum of
      wonders. Each type of light--­from radio waves to gamma-rays--reveals
      something unique about the universe. Some wavelengths are best for studying
      black holes; others reveal newborn stars and planets; while others
      illuminate the earliest years of cosmic history.

      NASA has many telescopes "working the wavelengths" up and down the
      electromagnetic spectrum. One of them, the Fermi Gamma-Ray Telescope orbiting
      Earth, has just crossed a new electromagnetic frontier.
      A new ScienceCast video takes viewers on a trip to the edge of the
      electromagnetic spectrum, where mysterious objects are puzzling astronomers.
      [_Play it_ (http://www.youtube.com/watch?v=1hIF36ty1Eo) ]

      "Fermi is picking up crazy-energetic photons," says Dave Thompson, an
      astrophysicist at NASA's Goddard Space Flight Center. "And it's detecting so
      many of them we've been able to produce the first all-sky map of the very high
      energy universe."

      “_This_ (http://science.nasa.gov/media/medialibrary/2012/03/16/skymap.jpg)
      is what the sky looks like near the very edge of the electromagnetic
      spectrum, between 10 billion and 100 billion electron volts.”
      The light we see with human eyes consists of photons with energies in the
      range 2 to 3 electron volts. The gamma-rays Fermi detects are billions of
      times more energetic, from 20 million to more than 300 billion electron
      volts. These gamma-ray photons are so energetic, they cannot be guided by the
      mirrors and lenses found in ordinary telescopes. Instead Fermi uses a sensor
      that is more like a Geiger counter than a telescope. If we could wear
      Fermi's gamma ray "glasses," we'd witness powerful bullets of energy –
      individual gamma rays – from cosmic phenomena such as supermassive black holes and
      hypernova explosions. The sky would be a frenzy of activity.
      Before Fermi was launched in June 2008, there were only four known
      celestial sources of photons in this energy range. "In 3 years Fermi has found
      almost 500 more,” says Thompson.
      What lies within this new realm?

      "Mystery, for one thing," says Thompson. "About a third of the new sources
      can't be clearly linked to any of the known types of objects that produce
      gamma rays. We have no idea what they are."

      The rest have one thing in common: prodigious energy.
      An artist's concept of giant 'Fermi bubbles' emerging from the heart of
      the Milky Way. [_more_
      (http://www.nasa.gov/mission_pages/GLAST/news/new-structure.html) ]

      "Among them are super massive black holes called blazars; the seething
      remnants of supernova explosions; and rapidly rotating neutron stars called
      And some of the gamma rays seem to come from the 'Fermi bubbles' – giant
      structures emanating from the Milky Way's center and spanning some 20,000
      light years above and below the galactic plane.

      Exactly how these bubbles formed is another mystery.

      [Non-text portions of this message have been removed]
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