How did the universe begin?
What did the universe look like in the distant past? What was the beginning of the universe like? It will take at least several decades to find the answers above and fully understand the universe in the past. But thanks to the James Webb Space Telescope, which is extremely sensitive to infrared light, we are getting closer to the answer.
Astronomers explain that, as predicted before launch, the James Webb Space Telescope completely changes their perspective on the universe. In particular, the above telescope, which is specialized in infrared observation, shows the distant universe and suggests that stars may have formed earlier than we theoretically predict.
Which galaxy is officially the oldest?
The oldest galaxy prior to the James Webb Space Telescope observations is GN-z11, an irregular galaxy in the constellation Ursa Major observed by the Hubble Space Telescope. It is officially known as the most distant galaxy in the solar system so far, and has an observed redshift value of 11.09. Converting this into distance, it is approximately 13.4 billion light years, which is a galaxy only about 400 million years after the birth of the universe.
Astronomers use the James Webb Space Telescope to capture features in older objects that appear only in galaxies that formed shortly after the Big Bang (composed mainly of light elements and low-mass stars), and of older galaxies. It continues to break records.
However, it is known that many of the galaxies predicted to be old require further research, such as one of the galaxies predicted to be very close at 13.8 billion years turned out to be a galaxy formed later.
Discovery of early galaxies about 50 million years older than the oldest galaxies officially identified
An international astronomy research team led by Prof. Tommaso Treu at the University of California, Los Angeles (UCLA) reported observing GLASS-z12, a galaxy that occurred about 350 million years after the universe was created. (High resolution image shortcut)
A research team led by Professor Treou used the James Webb Space Telescope to capture old galaxies around the galaxy cluster Abell 2744 (also called Pandora’s Cluster). Older galaxies do not exist inside galaxy clusters, but exist billions of light years behind.
The galaxy marked (1) is a galaxy approximately 450 million years after the Big Bang, and the galaxy marked (2) is a galaxy only 350 million years after the Big Bang. Both galaxies are very close in time to the Big Bang, which occurred 13.8 billion years ago. In particular, the elongated galaxy marked (1) shows a very small size compared to our Milky Way.
The above picture shows an image of Abell 2744 taken with the James Webb Space Telescope’s near-infrared camera (NIRCam), along with a scale bar (angle measurement from Earth when looking up at the sky, measured in arc seconds, 1/1 degree). 3600, the full moon’s angular diameter is approximately 0.5 degrees), the north/east compass arrow shows direction when looking skyward, and reverses direction when looking down from above. Also, the colors show the NIRCam filters used to collect the light, and each color represents the visible light color used to represent infrared light passing through that filter.
In fact, the above galaxy was discovered at the edge of the galaxy cluster ‘Abell 2744’ last July. At the time of discovery, it was named ‘GLASS-z13’ because it was predicted to have a higher redshift of z = 13.1, but subsequent studies revealed that the redshift of the above galaxy was approximately z = 12.4 (+0.1-0.3) It was renamed ‘GLASS-z12’. The above galaxy was discovered along with GLASS-z10, which is predicted to rival GN-z11, the oldest galaxy. (Link to Related Articles)
The research team explains that the extremely sensitive NIRCam instrument completely changes our view of the universe, and that the discovery of an object that existed only a few hundred million years after the Big Bang suggests that the beginning of the galaxy above may have been earlier than thought. do. In fact, for the above galaxies to exist, formation must begin only 100 million years after the Big Bang, and through this, it can be predicted that the dark age of the universe, which was composed of gas and dark matter without any light, ended much sooner than expected.
The research team led by Professor Treou predicted that the two galaxies discovered this time could be low-mass galaxies composed of very bright and hot Population III stars. These are first-generation stars composed of only primitive hydrogen and helium, before the appearance of heavy elements produced through stellar nuclear fusion, and are astronomical objects that have never been observed.