A team of researchers has spent years studying the universe to find the earliest objects in it and has found the most distant and, therefore, oldest galaxy ever discovered.
An article detailing the discovery was published in this month's Astrophysical Journal Letters, with Adi Zitrin, a NASA postdoctoral scholar in astronomy, and Richard Ellis, a recent retiree of CalTech, describing evidence of a galaxy called EGS8p7, which is over 13.2 billion years old. The universe itself is estimated to be 13.8 billion years old.
EGS8p7 was originally identified earlier this year as a possible candidate for investigation based on data collected by NASA's Hubble Space Telescope.
The researchers then used the multi-object spectrometer for infrared exploration, or MOSFIRE, to determine the redshift of the galaxy. Determining the redshift of a galaxy essentially analyzes the color shift of the light from that galaxy due to the Doppler effect.
Redshift is often used to measure the distance to galaxies, but when looking at extremely early objects, it is difficult to use. Right after the Big Bag, the universe was basically a big mess of charged particles.
Photons were scattered by free electrons and thus the early universe could not transmit light. Within 380,000 years after the Big Bang, the universe had cooled down enough for the free electrons and protons to combine, allowing light to transmit through the universe.
EGS8p7 certainly seems to be extremely old, but researchers were a little confused by some of the light signatures that the galaxy emitted, seeming too bright for the galaxy to be so old. This is because of the fact that in the early universe there was a lot of neutral hydrogen, which absorbed much of the light emitted by things such as stars. It wasn't for around a billion years that light was able to pass.
Theories for the brightness of the galaxy include the hypothesis that EGS8p7 includes a core of extremely hot stars.
