Friday, October 25, 2013

Record Galaxy tracked: How astronomers overcome cosmic distances - ABC Online

astronomers have detected a galaxy that is almost as old as ours. But it is so far away that their light was 13 billion years until the earth move. It’s like a glimpse into the earliest history of the Universe.

An international group of astronomers discovered till now the most distant galaxy in the universe. They existed 700 million years after the Big Bang, which took place 13.8 billion years ago. This report researchers led by astronomer Steven Finkelstein of the University of Texas at Austin in a study in the scientific journal “Nature”.

Addition to the new record holder, who received the peculiar astronomical term “z8_GND_5296″ the sky researchers found islands of stars that may are further away and must have formed earlier. However, the astronomers could not yet be confirmed by spectroscopic follow-up observations.

Determine the distance of distant galaxies, the researchers from the redshift of their light. It results from the expansion of the universe. By the expansion of space, the light of all celestial objects is stretched on its way to Earth. This strain is more pronounced the longer the photons (light particles) are out on their journey through the cosmos. The duration of this trip, the physicists can determine based on the wavelengths of light emitted by the atoms of certain elements.

If the light is separated into its spectrum, these wavelengths can find it in the form of lines. The wavelength of the light emitted by stationary atoms can be determined very precisely in the laboratory. From the comparison with the spectral lines in the light of the strength of the flying galaxies in the red spectral shift can be determined. The redshift becomes the measure of cosmic distances – it is specified as a dimensionless number for the same time it is a measure of the age of a cosmic object, the larger the redshift, the sooner it was already present in space

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