Chile: Eduardo Banados had three nights to spot something that might not even exist: a supermassive black hole close to the beginning of time.
At the Las Campanas Observatory in Chile, perched high atop a mountain in the world’s driest desert, he scanned for the signature of a massive, invisible sinkhole in the sky slurping up a whirlpool of brilliant, hot matter.
Just before sunrise on the third night, he found it. Way out at the very edge of the observable universe, there loomed a black hole 800 million times more massive than the sun. The signal had traveled more than 13 billion light-years across time and space to reach Banados’ telescope.
In a paper published in the journal Nature Wednesday, Banados and his colleagues reports that their new find is the oldest and most distant black hole ever discovered.
The object’s size is stunning, Banados said, because it existed just 690 million years after the Big Bang, when the universe was just 5 percent of its current age and still emerging from an enigmatic era known as “the Dark Ages.”
That such a large black hole can exist so early in time will shape models of how black holes form. And it will offer insight into the universe’s hard-to-study early years.
“If the universe was a 50-year-old person,” Banados explained. “Now we have a photograph of that person as a toddler . . . when they were two and a half.”
The Dark Ages began just a few hundred thousand years after the Big Bang, once the hot particle slurry that constituted the early universe condensed into atoms. The universe was getting bigger and colder in this period, filling up with a featureless fog of hydrogen gas. There were no galaxies, stars or supernovas (which appear when stars explode) – othing that gave off light. The only form of radiation was a very weak hydrogen glow.
This state of affairs lasted for hundreds of millions of years. Yet sometime during this inscrutable period, the universe as we know it emerged. Gravity pulled hydrogen into the first gas clouds, from which the first stars were born. The radiation from the newly formed objects broke hydrogen atoms apart into their constituent particles – protons and electrons – finally dispelling the chilly fog.
This process, called “reionization” because previously neutral hydrogen atoms became ions with an electric charge, was the last major transition in the universe’s history. Understanding the reionization epoch, Banados said, is one of the “frontiers of astrophysics.”
In a companion paper published in the Astrophysical Journal Letters, the scientists report another odd finding: The galaxy where ULAS J1342+0928 dwells was generating new stars “like crazy,” Banados said. Objects the size of our sun were emerging 100 times as frequently as they do in our own galaxy today.