Loading ...
Sorry, an error occurred while loading the content.
 

Re: Yahoo! News Story - Huge gamma-ray blast spotted 12.2 bln light-years from earth

Expand Messages
  • mahtezcatpoc
    ... Huge gamma-ray blast spotted 12.2 bln light-years from earth Thu Feb 19, 3:58 pm ET AFP/NASA – WASHINGTON (AFP) – The US space agency s Fermi telescope
    Message 1 of 2 , Feb 20, 2009
      --- In thefixedstars@yahoogroups.com, Mark Andrew Holmes
      <mahtezcatpoc@...> wrote:
      >
      > Mark Andrew Holmes (mahtezcatpoc@...) has sent you a news article.
      > (Email address has not been verified.)
      > ------------------------------------------------------------
      > Personal message:
      >
      >
      >
      > Huge gamma-ray blast spotted 12.2 bln light-years from earth
      >
      > http://news.yahoo.com/s/afp/20090219/sc_afp/sciencespaceastronomy


      Huge gamma-ray blast spotted 12.2 bln light-years from earth

      Thu Feb 19, 3:58 pm ET AFP/NASA –

      WASHINGTON (AFP) – The US space agency's Fermi telescope has
      detected a massive explosion in space which scientists say is the
      biggest gamma-ray burst ever detected, a report published Thursday in
      Science Express said.

      The spectacular blast, which occurred in September in the Carina
      constellation, produced energies ranging from 3,000 to more than five
      billion times that of visible light, astrophysicists said.

      "Visible light has an energy range of between two and three electron
      volts and these were in the millions to billions of electron volts,"
      astrophysicist Frank Reddy of US space agency NASA told AFP.

      "If you think about it in terms of energy, X-rays are more energetic
      because they penetrate matter. These things don't stop for anything --
      they just bore through and that's why we can see them from enormous
      distances," Reddy said.

      A team led by Jochen Greiner of Germany's Max Planck Institute for
      Extraterrestrial Physics determined that the huge gamma-ray burst
      occurred 12.2 billion light years away.

      The sun is eight light minutes from Earth, and Pluto is 12 light
      hours away.

      Taking into account the huge distance from earth of the burst,
      scientists worked out that the blast was stronger than 9,000
      supernovae -- powerful explosions that occur at the end of a star's
      lifetime -- and that the gas jets emitting the initial gamma rays
      moved at nearly the speed of light.

      "This burst's tremendous power and speed make it the most extreme
      recorded to date," a statement issued by the US Department of Energy
      said.

      Gamma-ray bursts are the universe's most luminous explosions, which
      astronomers believe occur when massive stars run out of nuclear fuel
      and collapse.

      Long bursts, which last more than two seconds, occur in massive stars
      that are undergoing collapse, while short bursts lasting less than
      two seconds occur in smaller stars.

      In short gamma-ray bursts, stars simply explode and form supernovae,
      but in long bursts, the enormous bulk of the star leads its core to
      collapse and form a blackhole, into which the rest of the star falls.

      As the star's core collapses into the black hole, jets of material
      blast outward, boring through the collapsing star and continuing into
      space where they interact with gas previously shed by the star,
      generating bright afterglows that fade with time.

      "It's thought that something involved in spinning up and collapsing
      into that blackhole in the center is what drives these jets. No one
      really has figured that out. The jets rip through the star and the
      supernova follows after the jets," Reddy said.

      Studying gamma-ray bursts allows scientists to "sample an individual
      star at a distance where we can't even see galaxies clearly," Reddy
      said.

      Observing the massive explosions could also lift the veil on more of
      space's enigmas, including those raised by the burst spotted by
      Fermi, such as a "curious time delay" between its highest and lowest
      energy emissions.

      Such a time lag has been seen in only one earlier burst, and "may
      mean that the highest-energy emissions are coming from different
      parts of the jet or created through a different mechanism," said
      Stanford University physicist Peter Michelson, the chief investigator
      on Fermi's large area telescope.

      "Burst emissions at these energies are still poorly understood, and
      Fermi is giving us the tools to understand them. In a few years,
      we'll have a fairly good sample of bursts and may have some answers,"
      Michelson said.

      The Fermi telescope and NASA's Swift satellite detect "in the order
      of 1,000 gamma-ray bursts a year, or a burst every 100,000 years in a
      given galaxy," said Reddy.

      Astrophysicists estimate there are hundreds of billions of galaxies.

      The Fermi gamma-ray space telescope was developed by NASA in
      collaboration with the US Department of Energy and partners including
      academic institutions in France, Germany, Italy, Japan, Sweden and
      the United States.
    Your message has been successfully submitted and would be delivered to recipients shortly.