A Galaxy That Is Truly Far, Far Away
Earlier in December of 2020, scientists and astronomers peered into the sky and believed that they had discovered the farthest and oldest galaxy ever observed. A team of astronomers led by Nobunari Kashikawa, a professor in astronomy at the University of Tokyo, found the universe and named it GN-z11. Their goal was to find the oldest observable galaxy and learn more about how and when it formed. A quick disclaimer, GN-z11 is not the farthest galaxy ever. It is only the farthest that we can observe. This is because it takes time for light to travel to Earth. Therefore, we can only observe other galaxies after the light has hit us.
 |
| Image of GN-z11 |
The team has estimated that GN-z11 is 13.4 billion light-years away, or 134 nonillion kilometers (that's 134 followed by 30 zeros). Since the distance is so large, it is hard to verify if it is actually correct. To determine how far GN-z11 is from Earth, the team studied that galaxy's redshift. Redshift is the displacement of light of an astronomical object toward the red wavelength. To sum it up, the farther the object is, it will show a red wavelength of light. This is how astronomers also find exoplanets. The team also looked at GN-z11's emission lines. Emission lines are observable chemical signatures in the light coming from cosmic objects. By studying the redshift and emission lines of GN-z11, the team can estimate how far the galaxy actually is.
The team also attempted to use ultraviolet light and added a press release that the Hubble Telescope also detected the signature in the spectrum of GN-z11. However, Hubble cannot resolve ultraviolet emission lines. Luckily, there is a solution to this—the W. M. Keck Observatory in Hawaii.
 |
| This is a diagram demonstrating redshift. You can see in the top image that the farther the sun gets, the light starts to shift towards the red spectrum of light. Vice versa, the closer the sun gets, the light starts to shift towards the blue spectrum of light. This phenomenon is called a blueshift. |
The W. M. Keck Observatory was a two telescope astronomical observatory near Mauna Kea's summit in Hawaii. The team was able to use the MOSFIRE instrument in the Keck 1 telescope. MOSFIRE stands for Multi-Object Spectrometer for Infra-Red Exploration. MOSFIRE is a multi-object spectrograph wide-field camera for infrared. Its unique feature is the cryogenic Configurable Slit Unit (CSU). The CSUs in MOSFIRE helped it stay remotely controlled and reconfigurable in under six minutes without thermal cycling. Without these bars, MOSFIRE transforms into a wide-field imager. MOSFIRE was developed by teams from the University of California (UCLA), the California Institute of Technology (Caltech), and the University of California, Santa Cruz (UCSC).
 |
| Diagram of MOSFIRE |
The team decided to use MOSFIRE because it is a more up-to-date ground-based spectrograph. While using MOSFIRE, the team was able to observe and study the emission lines. If new observations confirm their findings, GN-z11 would be the most distant galaxy that we can currently keep.
Mind-boggling, literary!
ReplyDeleteAnd yet we haven't reached the end of the universe.
Or has it an end.Or has it a beginning,for that matter!
"The universe is beginning less, endless wonder,ever expanding,contracting somewhere.And all this is done with the same amount of Matter.This is the Celestial Dance ever in progress, appears dormant somewhere,but never resting."
ReplyDeleteSource of the quote unknown.