• Sat. Jul 31st, 2021

Astronomers Have Spotted the ‘Farthest and Oldest Galaxy Ever Observed


Jan 1, 2021

In a new study published in the Nature Astronomy journal, astronomers have observed the GN-z11 galaxy. They think that this is the farthest galaxy to be observed from earth.

“From previous studies, the galaxy GN-z11 seems to be the farthest detectable galaxy from us, at 13.4 billion light-years”, said Nobunari Kashikawa, a professor in the Astronomy Department at the University of Tokyo.

Kashikawa led a team of astronomers on a mission to discover the most distant observable galaxy as seen from earth. They also conducted this study to learn how and when this galaxy was formed. They think that GN-z11 might be the oldest galaxy.

The team analyzed this particular galaxy’s redshift, which shows the amount of light that has stretched out from the galaxy. From this study, the scientists were able to determine how far from the earth the galaxy is. If a cosmic object is close to the earth, its light will be less redshifted, and vice versa.

Another method used to determine how far away a cosmic object is is the object’s emission lines. These are bright lines of light emitted by an object in a galactic spectrum. The ultraviolet light spectrum is the most used spectrum to measure the emission lines.

Following these emission lines, astronomers can tell how far the light coming from a cosmic object has traveled to reach the earth. This information is used to evaluate the distance between the object and the earth.

To estimate how far the GN-z11 galaxy is from the earth, Kashikawa’s team used The Hubble Space Telescope (HST). This is one of the largest and versatile telescopes in the low Earth Orbit. It detected the ultraviolet emission lines several times, in the spectrum of this interesting galaxy.

Since the HST could not resolve the emission lines to the needed standards, the astronomers used a MOSFIRE. This is an up-to-date ground-based spectrograph, which is mounted to the Keck 1 Telescope. Keck 1 is one of the observatory telescopes by the W.M. Keck Foundation, located in Hawaii.

Using this spectrograph, the emission lines were examined in detail. This led to the conclusion that GN-z11 is the farthest galaxy from the earth in the whole universe.

This is only a thought from the calculations and estimates. To officially name GN-z11 as the farthest galaxy to be observed from earth, these claims would have to be backed up by more research.