Hubble's Deepest Cosmic Survey CompletedCategory: Science & Technology
Posted: December 14, 2012 07:45AM
Though time travel currently exists only in fiction, humanity does have the ability to view the past as far back as when the Universe was not even a billion years old. The NASA/ESA Hubble Space Telescope has recently completed a survey, led by researchers at the California Institute of Technology, that is its deepest yet at just 350-600 million years after the Big Bang. It has also shifted some positions of ancient galaxies and exposed more information of how the first galaxies formed.
After the big Bang, the Universe expanded rapidly and cooled enough for protons and electrons to bond and form hydrogen. Eventually this hydrogen collected together to form the first stars, which then reionized the hydrogen gas, but at the same time those stars collected together to form the first galaxies. Through all of this, the Universe has continued to expand, which enables us to determine the age of a galaxy by calculating the redshift of the spectra of light emitted by that ionized hydrogen cooling. The greater the redshift of the spectra, the farther the galaxy is. One of the galaxies caught in this survey was also the furthest galaxy yet observed at a redshift of 10, but according to the new survey it is even further at a redshift of 11.9.
Of course the survey did more than just set records as it also indicates that the first galaxies formed in a gradual process and not in one dramatic moment. Sadly Hubble may not be able to peer further back in time, due to its limitations, but its successor, the James Webb Telescope, is being built specifically for that purpose.