The Edge of Time

When searching for the secrets of the universe, astronomers look to the past. The current model of the universe’s formation is the big bang theory, which claims that the entirety of the universe’s existence swelled from a single point. Scientists estimate that this occurred 13.8 billion years ago.  If the time period between then and now was scaled down to the length of a day, humanity would emerge at about four seconds to midnight. Those four seconds are what is certain.

Documented by our DNA, cave paintings, and oral history, humanity truly knows itself better than any function of the universe. We know that humans require oxygen to live, inhabit the planet Earth, and are, as a whole, infinitely curious. So to satiate the confusion and craving that fills the collective mind of humanity, the astronomy community has set out to discover what happened in the eleven hours fifty-nine minutes and 56 seconds before humans emerged.

An article published by a team of Caltech scientists based on research that occurred at W. M. Keck Observatory in Hawaii, claiming to have found the earliest known galaxy, is one milestone in this investigation.  Prior to this research, astronomers estimated that galaxies, or systems of stars, interstellar gas, dust, and dark matter bound by gravitational attraction, first formed in the 500 years after the big bang.

This galaxy, known by the poetic title of EGS8p7, is estimated to exceed 13.2 billion years old, thus invalidating that the previously established timeframe and making this galaxy one of the oldest objects in the universe. The revolutionary research published on August 28th, 2015, is centered on a process called spectrographic analysis, through which scientists measure wavelengths or spectral lines to determine a galaxy’s redshift, or the bending of an object’s light in relation to earth. Typically, the distance from the earth can be only be determined by the redshift of galaxies relatively nearby to earth. This is due to the early universe’s inability to transmit light.

The anomaly that causes many remote galaxies to remain undetected is due to the fact that the universe lacked structure for thousands of years after its inception. During this time, free electrons roamed around this celestial expanse randomly causing protons to be dispersed erratically as well. After the universe had sufficiently cooled, free electrons coupled with protons to create the first hydrogen atoms thus ionizing the universe and allowing light to travel unencumbered. The process of ionization repeated when the first galaxies surfaced and were able to reionize the clouds of neutrally charged hydrogen atoms that had appeared.

The makeup of EGS8p7, whose age places it among those first galaxies, confounds scientists due to the presence of its Lyman-alpha, a concept whose definition can be simplified to a spectral line of hydrogen gas heated by the ultraviolet light emanating from a galaxies newborn stars. Lyman-alpha lines are a frequently used tool in determining galaxy formation, however, in this instance the existence of one poses a specific problem.

At 13.2 billion years, scientist previously posited that the galaxies would not have been able to sustain Lyman-alpha lines because the clouds of neutral atoms would have absorbed the Lyman-alpha lines and similar radiation produced by the burgeoning galaxies in the ionization process. Adi Zitrin, the publisher of this research and a NASA Hubble Postdoctoral Scholar in Astronomy, says this of the phenomenon: “If you look at the galaxies in the early universe, there is a lot of neutral hydrogen that is not transparent to this emission. We expect that most of the radiation from this galaxy would be absorbed by the hydrogen in the intervening space. Yet still we see Lyman-alpha from this galaxy.”

This data captures a view of the universe’s infantile stages, which is causing the scientific community to rethink its notion of the ionization process. When scientists are able to fully understanding how the universe was initially ionized, humankind will hopefully be able to understand the universe’s expansion, evolution, and the beginnings of those eleven hours fifty-nine minutes and 56 seconds as clearly as we do our own beginnings.

— Colette Juran, Staff Writer

Posted by on September 15, 2015. Filed under World News. You can follow any responses to this entry through the RSS 2.0. You can leave a response or trackback to this entry

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