The farthest galaxy discovered: 30 billion light-years from Earth
Astronomers from Texas A&M University and the University of Texas at Austin have discovered the farthest galaxy known to us. According to spectrography data, it is located at a distance of about 30 billion light-years from the Solar system (or from our Galaxy, which in this case is not so significant, because the diameter of the Milky Way is only 100 thousand light-years).
The farthest object in the universe received the romantic name z8_GND_5296.
“It’s amazing to know that we are the first people in the world to see him,” said Dr. Vithal Tilvi, co-author of the scientific paper, which is now published online (use sci-hub.org for free viewing of scientific papers ) .
The discovered galaxy z8_GND_5296 formed 700 million years after the Big Bang. Actually, in this state, we see it now, because the light from the newborn galaxy has just reached us, having covered a distance of 13.1 billion light years. But since the Universe was expanding in the process, for this minute, as calculations show, the distance between our galaxies is 30 billion light-years.
In newborn galaxies, it is interesting that there is an active process of formation of new stars. If in our Milky Way appears one new star a year, then in z8_GND_5296 - about 300 a year. What happened 13.1 billion years ago, we can now calmly observe through telescopes.
The age of distant galaxies can be determined by the cosmological redshift caused, among other things, by the Doppler effect. The faster the object moves away from the observer, the stronger the Doppler effect is manifested. Galaxy z8_GND_5296 showed a redshift of 7.51. About a hundred galaxies have a redshift of more than 7, that is, they formed before the universe turned 770 million years old, and the previous record was 7.215. But only in a few galaxies is the distance confirmed by spectrographic data, that is, by the Lyman alpha spectral line (about it below).
The radius of the universe is at least 39 billion light years. It would seem that this contradicts the age of the Universe at 13.8 billion years, but there is no contradiction, given the expansion of the space-time tissue itself: there is no speed limit for this physical process.
Scientists do not quite understand why it is not possible to observe other galaxies up to 1 billion years old. Distant galaxies are observed by a clear manifestation of the spectral line L α (Lyman alpha), which corresponds to the transition of an electron from the second energy level to the first. For some reason, in galaxies younger than 1 billion years, the Lyman alpha line is becoming increasingly weak. One of the theories is that just at that time the Universe was transitioning from an opaque state with neutral hydrogen to a translucent state with ionized hydrogen. We simply cannot see the galaxies that are hidden in the “fog” of neutral hydrogen.
How did z8_GND_5296 manage to break through the fog of neutral hydrogen? Scientists suggest that she ionized the immediate vicinity, so that protons could break through. Thus, z8_GND_5296 is the first galaxy known to us that emerged from an opaque mash of neutral hydrogen that filled the Universe in the first hundreds of millions of years after the Big Bang.