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  • Only six hundred million years after the big bang, the universe was in a fog.

  • this is what the universe looked like before any galaxies had formed

  • Here, there are no luminous objects

  • no stars

  • and certainly no galaxies

  • When the universe cooled down after the Big Bang

  • electrons and protons combined

  • to form neutral hydrogen gas

  • At this time in our history

  • no photons could pass through

  • the universe was opaque.

  • This dark age ended when the first stars formed and their intense ultraviolet radiation

  • pierced the veil

  • by splitting the hydrogen atoms

  • back into electrons and protons

  • In this simulation

  • the dark areas are opaque,

  • the blue areas translucent.

  • The fog lifted

  • when stars were born.

  • These hot young stars blew away the cosmic fog of hydrogen gas with ultraviolet radiation

  • and these stars formed into the very first galaxies.

  • clearing the way for their photons

  • to begin their too long,

  • arduous journey across creation.

  • The first galaxies ever to form,

  • lifed the universal fog forever.

  • The era for reionization had begun.

  • On October 19th 2010,

  • astronomers announced a measurement of one of the first galaxies

  • ever to form in the universe,

  • and it formed during this period.

  • Sensitive instruments on the European Southern Observatory's Very Large Telescope

  • recorded a spectrum

  • of a galaxy first imaged by the Hubble Space Telescope in January, 2010

  • Starting with a new Ultra Deep Field image taken in January, 2010,

  • with the upgraded Wide Field Camera 3

  • sensitive to the infrared

  • astronomers looked at every faint galaxy within it

  • these faint galaxies were among the first in existence.

  • From these faint smudges,

  • candidates for further study with the ESO SINFONI spectrograph were selected.

  • These galaxies were so faint,

  • it wasn't at all clear

  • if a spectrum could be obtained.

  • Lying in a very obscure region of the Ultra Deep Field

  • the ESO astronomers pointed the Very Large Telescope spectrograph

  • at one of the faintest objects they could see in the image.

  • Early in time,

  • this galaxy was once exceedingly bright in the ultraviolet,

  • but by the time it's light traversed the observable universe to land on our detectors,

  • its photons had been diminished to a faint, red glow.

  • The feeble red light from this galaxy

  • was collected for over sixteen long hours resulting in a spectrum

  • with a measured redshift of 8.6

  • This galaxy was alive

  • 13.1 billion years ago

  • when the cosmos was still in its infancy,

  • and its redshift is the largest ever recorded

  • anywhere in the universe.

  • Looking at galaxies this remote is very difficult,

  • but they're crucial to our understanding of how galaxies came into existence

  • This observation of a galaxy

  • early in the lifetime of the universe of came as a surprise

  • Galaxies, it seems,

  • have existed much earlier

  • than was previously thought.

  • This distant galaxy not only helped clear the early hydrogen fog blanketing the universe,

  • it is now also

  • helping to clear the fog of ignorance

  • in our understanding

  • of the earliest period of existence.

Only six hundred million years after the big bang, the universe was in a fog.

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