Some of the ingredients needed for life appeared shortly after the universe began.
According to a new analysis of a pair of galaxies at the dawn of time, water was present in the universe just 780 million years after the Big Bang – when the universe was only 5 percent of its present age.
This suggests that while there were still relatively few heavy elements, no time was wasted in creating molecules.
Galaxies, at least as we see them after their light has passed 12.88 billion years, are in the process of merging into one large galaxy known collectively as SPT0311-58, and they are among the most oldest known galaxies in the universe.
It is believed that the gravitational disruptions caused by their interaction cause a wave of star formation that uses up all the available molecular gas. But there is still enough gas for astronomers to peer into, obtaining spectral signatures that indicate the presence of certain molecules.
“Using ALMA in High Resolution [Atacama Large Millimeter/submillimeter Array] By observing molecular gas in a pair of galaxies collectively known as SPT0311-58, we have discovered water and carbon monoxide molecules in the larger of the two galaxies, ”says astronomer Sreevani Yarugula of the University of Illinois.
“Oxygen and carbon in particular are first-generation elements, and in the molecular forms of carbon monoxide and water, they are critical to life as we know it.”
Because light from galaxies in the early universe traveled so far to reach us, it is very faint and much more difficult to discern in detail than from galaxies that are relatively close. However, the interstellar medium in these galaxies is rich in dust, which can help reveal the presence of water.
The dust absorbs ultraviolet radiation from the stars and re-emits it as far-infrared light, the researchers said. This infrared radiation excites water molecules in the interstellar medium, which generates radiation that can be detected with a sensitive telescope like ALMA in Chile.
Finding this water so early in the history of the universe could help scientists understand the origin and evolution of the building blocks of life in the universe.
“This galaxy is the most massive high redshift galaxy currently known, or at a time when the universe was still very young,” explains Yarugula.
“It is more gas and dusty than other galaxies in the early universe, giving us many potential opportunities to observe numerous molecules and better understand how these life-creating elements influenced the early universe.”
Determining the composition of the molecular clouds from which stars form can help us better understand how much gas is there, the rate at which it turns into stars, and how many stars formed in the early universe.
This was a time when the rate of star formation could only be described as frantic – thousands of times more productive than in recent times, due to the large amount of dust and gas from which stars could form.
“This study not only provides answers about where and how far water can exist in the Universe, but also raised the big question: How did so much gas and dust gathered to form stars and galaxies at such an early stage in the existence of the Universe? “says Yarugula.
“The answer requires further study of these and similar star-forming galaxies to better understand the structure formation and evolution of the early universe.”
Research published in Astrophysical Journal…