Astronomers have announced a discovery that rewrites our understanding of what the Universe looked like in the first few hundred million years after the Big Bang. A study of a super-hot and extremely active region of the young Universe, where the first cosmic objects were forming, has been published in the journal Monthly Notices of the Royal Astronomical Society. The central object of the work is galaxy Y1 — the most distant galaxy in which cosmic dust has ever been detected. Observations reached a depth of about 13 billion light-years, making it possible to capture events that occurred only a few hundred million years after the birth of the Universe.
A super-hot cradle for the first objects
The discovery was made possible by the ALMA array of radio telescopes, located in the Chilean desert. Galaxy Y1 turned out to be rich in dust, gas, and intense radiation, creating conditions for the active clumping of particles. In addition to dust, the object emits a colossal amount of infrared heat: the gases and dust inside it are heated to high temperatures, so they move and stick together significantly faster than in more “cold” galaxies. In terms of the processes involved, Y1 resembles the Orion or Sagittarius nebulae, familiar to astronomy enthusiasts, but unfolds on an incomparably larger scale.
180 solar masses per year: an unprecedented rate
The key figure of the discovery is the rate of matter formation. If the Milky Way produces material equivalent to roughly one solar mass per year, then in this newly discovered cosmic region the figure reaches almost 180 solar masses per year. Such a rate indicates that early galaxies went through a phase of rapid growth with no direct counterparts in today’s calm galactic environment.
How hot dust resolves the paradox
The discovery of Y1 may solve a long-standing puzzle in astrophysics. It was previously believed that some early galaxies contained too much dust for their age, since dust usually forms only after stars complete their life cycle and explode. Researchers show that earlier calculations may have been incorrect: a small amount of extremely hot dust, like that in Y1, produces the same observational signal as much larger volumes of cold dust. This explains how the first galaxies managed to grow to significant sizes in a relatively short time by cosmic standards.
Why this rate is not eternal
It is important to emphasize that such a high rate of star formation cannot continue indefinitely. The reserves of gas and dust needed for star formation in Y1 must be depleted relatively quickly. Thus, the galaxy has been captured in a rare “window” of maximum activity, making it a particularly valuable object for understanding the early history of the Universe.
