A team of Caltech astronomers searching for the oldest objects in the cosmos report that they have spotted the most distant galaxy ever found. the galaxy called EGS8p7 which is more than 13.2 billion years old challenges the current theories about the evolution of the early universe.
Scientists have long theorized that the first galaxies evolved roughly 500 million years after the Big Bang, the new discovery may challenge the currently established timeline of the cosmos.
Astrophysicists Adi Zitrin, a Hubble postdoctoral scholar in astronomy, and Richard Ellis, professor of astrophysics at University College London first spotted EGS8p7 using the Hubble and Spitzer space telescopes. But their spectral analysis yielded some surprising results.
The discovery was published on August 28, 2015 in Astrophysical Journal Letters by Adi Zitrin, a NASA Hubble Post-doctoral Scholar in Astronomy and colleague Richard Ellis who recently retired after 15 years at Caltech and is now a professor of astrophysics at University College of London.
According to Zitrin the team is currently doing more thorough calculations to establish if the time-line of re-ionization needs to be revised. The time-line plays a major role in better understanding the evolution of the universe.
The universe itself is currently believed to be 13.8 billion years old and the study confirms earlier revisions of the earliest galaxy formations thought to be possible as early as 200 million years after the Big Bang.
Using an instrument called MOSFIRE (multi-object spectrometer for infra-red exploration) at he W.M. Keck Observatory in Hawaii, a spectrographic analysis of the galaxy revealed it’s age. The method measures redshift which is an effect similar to the Doppler effect on sound waves. With celestial objects light is used instead of sound. Redshift is commonly used to measure the distance of galaxies, stars and other celestial objects but because light is used for measurement, the method is difficult to use on the most distant and faintest objects in the universe.
It is currently believed that the conditions prevalent in the early universe makes the detection of light impossible. Up until 380.000 years of formation the universe consisted of a soup of neutral electrons, protons and photons believed to block all passage of light. When the universe was around 500 million years old the first galaxies are thought to have “turned on” and re-ionized the neutral gas creating the conditions of today’s universe.
Prior the re-ionization occurred clouds of neutral hydrogen absorbed radiation emitted by the newly formed galaxies. The study detected the so called Lyman-alpha line which according to current theories should not be possible to detect at such an early age, as such it may cause the current theories about the early formation of the cosmos to be revised.
“The surprising aspect about the present discovery is that we have detected this Lyman-alpha line in an apparently faint galaxy at a time when the universe should be full of absorbing hydrogen clouds,” according to Ellis.
A theory for the discrepancy is that EGS8p7 which is an unusually luminous galaxy may be powered by a group of very hot young stars. The stars may have special properties that enabled the galaxy to create a massive bubble of ionized hydrogen much earlier than thought possible for more common galaxies at the time says Sirio Belli, a Caltech graduate student who worked on the project.
updated 00:47 pm