Light, ahoy!
THE farthest hazy horizons of the universe seem to emerge clear, as astronomers working with the Keck telescope in Hawaii have recently claimed to have observed the most distant galaxy (and the oldest) known to humankind as yet. Embedded in the constellation Virgo some 14 billion fight years away, this galaxy is believed to have 'been formed only a billion years after the 'Big Bang' - when the universe is supposed to have been born.
"Looking at the very distant parts of the universe is essentially looking back in time, because, an image one billion light years away has taken a billion years to reach the earth," said Thomas Barlow, one of -the four astronomers at the California Institute of Technology (Caltech), credited with the discovery.
In astronomy, the distance of the observed objects are gauged by the so called 'red shift' in the corresponding spectra (red corresponds to the highest wavelength in the visible spectral range) which might increase or decrease with the movement, of -the objects. When the source of electromagnetic radiation is receding from the observer, a wavelength longer than the original signal is observed; and the further the galaxy is from the earth, the faster, according to Hubble's Law, it is moving away from us.
I Thus, light from an object at-a very high red shift implies that it is located very far out in the space. The red shift of this newly discovered galaxy was measured at 4.38. Scientists Wallace Sargent, Li-min Lu, Donna Womble and Thomas Barlow reported their findings in the current issue of the Astrophysical Journal Letters. Lu, a Hubble Fellow at the Caltech, said that the discovery was made while observing a distant quasi-stellar object - the source of brightest light :mong all celestial objects. When they examined the quaser spectrum, the astronomers noted certain dark lines in it, which indicated that 'something' was absorbing certain wavelengths of the light originating from the quaser.
The analysis of this :bsorption spectrum' of the quaser led to the calculation of the red shift of the 'something', that turned out to be the yet unnamed galaxy.-The apparent distance of this galaxy is about 200 million light years.
An intertesting fallout of this observation is the detection of tiny quantities of-carbon, oxygen, silicon, aluminium and iron in the spectrum of the new galaxy. Cosmologists bel -ieve that almost all the carbon found in the universe was formed in the stars. Jeremiah P Ostriker, an astrophysicist from Princeton University, had predicted years ago, that cosmic instabilities after the Big Bang could have triggered star formation before the first galaxies formed. David Tytler, an astrophysicist at the University of California at San Diego, however, proposes that the carbon was created in stars which were located in the galaxies, which themselves were in an infantile stage.
Therefore, based on the assumption that the Big Bang occured a billion years before all this happened, the discovery of carbon and iron pushes back the birth date of the new galixy to almost about 14 billion years. Astronomers hope'that studies on this galaxy would provide strong insights into the universe and the formative period of several galaxies, including the Milky Way - home to our very own mother Earth.