Take a picture of the first gleam in the universe

Astronomers have discovered a cloud of sparkling cosmic dust at the age of 4% of the current age of the universe, making it one of the first rays of the universe ever recorded. .

A group of international astronomers, led by Nicolas Laporte from the University of London, used ALMA glasses to observe A2744_YD4, the youngest and most distant galaxy ever observed.

They were surprised to find that this galaxy, though very young, contained many interstellar gas dust, formed by the death of previous stars.

This galaxy is located in the cosmic region of only 600 million years old, while the universe we live in is about 13.7 billion years old. This new observation gives a whole new perspective on the birth of the first stars in the universe.

"A2744_YD4 is not only the furthest galaxy observed by ALMA, it also contains a lot of gas dust, which is evidence that supernova explosions have been taken and polluted this galaxy," Nicolas Laporte said.

An illustration of the young galaxy A2744_YD4 appeared when the universe was only 600 million years old.(Photo: ESO / M. Kornmesser).

Clouds of gas dust are composed mainly of silicon, carbon and aluminum, which are tiny particles of about one millionth of a centimeter. These chemical elements often appear around a spectacular, dead star in supernova explosions.

In the universe today, abundant dust and gas contribute to the creation of stars, planets and new structures of the galaxy. However, at the time of the first 600 million years of the universe, the amount of dust was very scarce, so finding a large amount of gas in this galaxy surprised astronomers.

Dust gas galaxy A2744_YD4 is located in a giant galaxy cluster named Abell 2744 . Because a phenomenon called "gravitational lens" , this galaxy cluster is like a giant telescope in the universe, which helps enlarge A2744_YD4 more than 1.8 times, allowing researchers to look deeper into the universe.

This observation also found that light emission of oxygen is ionized from A2744_YD4. This is the earliest known ionization of oxygen in the universe, far beyond the time of discovery ever made by ALMA in 2016.

The team estimates that A2744_YD4's dust content is about 6 million times the mass of the Sun, while its stars only have about 2 million times the mass of the Sun.

The team also measured the rate of star formation in A2744_YD4, and found that about 20 stars that are equivalent to the Sun are formed each year, while our Milky Way only produces a new star in the same Period.

Dust gas galaxy A2744_YD4 is located in a giant galaxy cluster named Abell 2744.

"This ratio is not normal compared to a galaxy far away, but it confirms the existence of gas dust in A2744_YD4. However, there is still a pity when we do not see it firsthand. the formation of this galaxy, because it was created 200 million years ago, " said co-author Richard Ellis.

This means, star formation in this galaxy began at least 200 million years ago, if we look deeper and observe at that time, we will learn more interesting things. No one has ever been known.

The Sun and the planets in the Solar System are next generation products, formed when the universe was under 10 billion years old. By studying deeply about the first celestial bodies in the universe, we will know our own origins.

"With ALMA, the prospect of making deep observations of the universe's past will become easier and we will have a higher chance of meeting young galaxies like this," Ellis added.