According to a recent studythe universe would have « ten times more » galaxies than scientists thought so far, bringing the number of galaxies in the Universe to more than 2,000 billion.
How many galaxies are there in the Universe? The images captured by Hubble Deep Field, taken in the mid-1990s, gave a first idea of the question. It was then estimated that the observable Universe contained between 100 and 200 billion galaxies, each containing several hundred billion stars. But according to a recent study by Christopher Conselice of the University of Nottingham, UK, this figure is at least ten times too low.
Using data from the Hubble Space Telescope developed by NASA with the European Space Agency, but also from other telescopes, images were modeled in 3D. The researchers then extrapolated the number of galaxies present at different times in the history of the universe. They then realized that our current telescopes can only study 10% of galaxies. Thus, 90% of the galaxies in the observable Universe are currently too faint and too far away to be perceived on our own.
« It’s amazing to think that 90% of the galaxies in the cosmos have yet to be studied »said Christopher Conselice. “Who knows what we will discover when we are able to study these galaxies with the next generation of telescopes? » did he interrogates in a press release published following the publication of his study in the journal Astrophysical Journal.
Questioned by AFP, François Hammer, astronomer at the Paris Observatory and specialist in the formation of galaxies, considered the study “interesting”, but expressed some reservations as to the precise number of galaxies contained in the Universe: “Professor Conselice has done the best we can do in our time. But his result cannot be considered the last word,” said the astrophysicist. « This is work that can only be confirmed when we have giant telescopes that will allow us to see much better in these distant regions. »
Note that the giant European Telescope E-ELT (European Extremely Large Telescope) 39 meters in diameter is being built in Chile by the European Southern Observatory (ESO). It should enter service “in 2024-2025”, specifies Mr. Hammer. This instrument will notably make it possible to observe extremely distant galaxies. What still reserve us beautiful surprises.
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