GENEVA — Monster black holes in the early universe may have taken an unusual route to becoming so massive.

Giant gas clouds in some of the universe’s first galaxies collapsed under their own gravity to form supermassive black holes, theoretical astrophysicist Lucio Mayer of the University of Zurich suggested December 15 at the Texas Symposium on Relativistic Astrophysics. The postulated process offers a major shortcut to supermassive status, as black holes are generally thought to start small and gradually grow by merging with each other and gobbling up matter. The mechanism also doesn’t rely on stars to spawn black holes in the first place.

Mayer’s proposal still has hurdles to clear before other astrophysicists accept it as viable. But if confirmed, it would solve the mystery of why astronomers keep spotting gargantuan black holes when the universe was less than a billion years old.

This supermassive conundrum boils down to timing. The first stars, some of them 100 times or more the mass of the sun, took shape a few hundred million years after the Big Bang. The largest ones exploded soon after and left behind black holes of roughly the same mass. Yet recent telescope observations reveal that by about 500 million years later, not very long on cosmic timescales, some black holes weighed in at 10 billion solar masses (SN: 4/4/15, p. 5). No matter how often ancient black holes feasted and combined forces, they would have had trouble growing by a factor of 100 million so quickly.