Could a black hole have existed before the very first stars ever twinkled? New James Webb Space Telescope observations are putting one of cosmology’s most basic assumptions to the test: that galaxies and stars need to exist in order to make black holes. Astronomers have found a “nearly naked” supermassive black hole, QSO1, whose properties indicate that it is a remnant from the earliest fraction of a second after the Big Bang.
Its target object is more than 13 billion light-years away, as it existed when the universe was a mere 700 million years old. Unlike black holes at the centers of galaxies in our time, QSO1 is surrounded by only a thin halo of dust and gas. It places its central mass at 50 million solar masses and the surrounding material at less than half that amount a dramatic flip of the usual proportion of the local universe, where central black holes are about a thousand times less massive than the galaxies they inhabit. This black hole is nearly naked, said Roberto Maiolino of Cambridge University. It seems that this black hole has formed without being preceded by a galaxy around it.
Chemical examination of the halo revealed it to be “pristine,” made up almost entirely of hydrogen and helium the light elements forged in the first three minutes after the Big Bang. The absence of heavy elements, or metals, that are formed in stars and disseminated by supernovae, indicates no star formation nearby. As Maiolino described, Here we’re witnessing a massive black hole formed without much of a galaxy, as far as we can say from the data.
This outcome is in line with the long-suspected but never-observed concept of primordial black holes, proposed in the 1970s by Stephen Hawking. There, density fluctuations in the hot dense early universe might have collapsed under their own gravity to form black holes of all sizes, some of which may have served as seeds for galaxy formation by gravity. These objects might also, in principle, be connected with exotic phenomena such as Hawking radiation or even dark matter.
JWST’s infrared capability was key to the detection of QSO1’s redshifted, weak light. Its detectors are able to penetrate the “Cosmic Dawn” era when the initial structures had developed from the early gas. These observations have already revealed other small, bright “red dots” that may be other early supermassive black holes, raising the question of how these bodies so quickly could form at such great masses. Standard growth models seeded from stellar remnants and accreting at rates limited by the Eddington limit struggle to explain their size on such young ages.
Direct collapse black holes are another theory that holds the expectation that in unusual situations, giant clouds of pristine gas could directly collapse into a supermassive black hole without fragmentation into stars. Simulations suggest it is possible if molecular hydrogen, a key coolant, is destroyed by intensive ultraviolet radiation from the neighboring galaxies, preventing star formation. The environment of QSO1 lacks the expected signs of such an event, so researchers favor primordial origin.
If QSO1 is primordial, it would have significant implications for physics. As Durham University cosmologist Andrew Pontzen noted, A confirmed primordial origin for black holes would have profound implications for fundamental laws of physics. It could recast our understanding of structure formation, the nature of dark matter, and the interplay between quantum mechanics and gravity.
Next-generation technology could supply the final proof. The next-generation gravitational wave observatories, the Einstein Telescope and Cosmic Explorer, will be sensitive to black hole mergers in all of the observable universe, including potential primordial ones. Their signals could reveal whether such objects were common in the early universe, and if they persist today. Combined with JWST’s deep-field observations, these detectors could map the population of early black holes with unprecedented precision.
QSO1 is currently one of the best candidates yet for a primordial black hole a possible survivor of the universe’s first heartbeat that still shapes the surrounding galaxies more than 13 billion years later.
