A startling study, which looked at data 10 times more comprehensive compared to previous similar efforts, found that half of all the stars that have ever existed were created between 9 and 11 billion years ago, with the other half created in the years since. What this means is an exponential fall in new stars being born, to the point that no more than 5 per­cent more stars will form over the re­main­ing his­to­ry of the cos­mos, even if we wait for­ev­er.

For years, scientists were confused by the disparity between the number of stars we can observe and the number of stars we know should have been created by the universe. Numerous studies have each looked at specific periods in our Universe’s history in order to assess star formation, however since multiple methods were used, it was fairly difficult to aggregate and establish a comparative conclusion.

Diagram above show how star production has decreased over billions of years.  The new re­sults in­di­cate that, meas­ured by mass, the pro­duc­tion rate of stars has dropped by 97 per­cent since its peak 11 bil­lion years ago. (c) D. Sobral

Diagram above show how star production has decreased over billions of years. The new re­sults in­di­cate that, meas­ured by mass, the pro­duc­tion rate of stars has dropped by 97 per­cent since its peak 11 bil­lion years ago. (c) D. Sobral

A team of international researchers decided to run a complete survey from the very dawn of the first stars using three telescopes — the UK Infrared Telescope and the Subaru Telescope, both in Hawaii, and Chile’s Very Large Telescope. Snapshots were taken of the look of the Universe at various instances in time when it was 2, 4, 6 and 9 billion years old  –  that’s 10 times as large as any previous similar study. The as­tro­no­mers con­clud­ed that the rate of forma­t­ion of new stars in the Uni­verse is now only 1/30th of its peak.

“You might say that the uni­verse has been suf­fer­ing from a long, se­ri­ous ‘cri­sis:’ cos­mic GDP out­put is now only 3 per­cent of what it used to be at the peak in star pro­duc­tion!” said Da­vid So­bral of the Uni­vers­ity of Lei­den in the Neth­er­lands.

“If the meas­ured de­cline con­tin­ues, then no more than 5 per­cent more stars will form over the re­main­ing his­to­ry of the cos­mos, even if we wait for­ev­er. The re­search sug­gests that we live in a uni­verse dom­i­nat­ed by old stars.”

According to the current accepted models of the Universe’s evolution, stars first began to form some 13.4 billion years ago, or 300 million years after the Big Bang. Now, these ancient stars were nothing like those commonly found through out the cosmos. These were like titans with respect to Olympus’ gods – standing at hundreds of times more massive than our sun. Alas, the giants’ life would’ve been short lived, quickly exhausting their fuel, they had only one million years or so worth of time. Lighter stars, like our own, in contrast can shine long and bright for billions of years.

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It’s from these huge, first stars that other smaller, more long-lived stars form as the cosmic dust was recycled. Our Sun, for ex­am­ple, is thought to be a third genera­t­ion star, and has a typ­i­cal mass, or weight, by to­day’s stan­dards. To identify star formations, the astronomers searched for alpha particles emitted by Hydrogen atoms, appearing as a bright red light.

“Half of these were born in the ‘boom’ that took place be­tween 11 and 9 bil­lion years ago and it took more than five times as long to pro­duce the rest,” So­bral said. “The fu­ture may seem rath­er dark, but we’re ac­tu­ally quite lucky to be liv­ing in a healthy, star-form­ing gal­axy which is go­ing to be a strong con­trib­u­tor to the new stars that will form.

“Moreo­ver, while these mea­sure­ments pro­vide a sharp pic­ture of the de­cline of star-forma­t­ion in the Uni­verse, they al­so pro­vide ide­al sam­ples to un­veil an even more fun­da­men­tal mys­tery which is yet to be solved: why?”

Results were published in the Monthly Notices of the Royal Astronomical Society.

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