For some time, physicists have been looking for primordial black holes, exotic objects that could have formed in the early universe, and given birth to a whole range of cosmic shenanigans.
Using a giant telescope 8.2 meters wide (ie 27 feet), physicists at the University of California, Los Angeles and the Kavli Institute for Physics and Mathematics of the Universe in Japan are looking for signs of these objects; Their discovery might even suggest that our universe grew into universes for babies when he was a young man.
What he hopes to see will not be exactly as outrageous as to look at alternative realities. But if their new models are correct and patient enough, they could find a primordial black hole (PBH) floating between us and a nearby galaxy.
The discovery of such an object has the potential to fill some gaps in our knowledge of a whole range of phenomena, from the nature of dark matter to the distribution of heavy elements in space.
More appealing, it could also be an indication of whether our Universe is just one of many in a multiverse-branched family tree once born as babies during cosmic inflation – although a lot of debate would remain. on the last point.
Primordial black holes have much in common with black holes that form from collapsed stars. Both are intense concentrations of matter that pinch the surrounding space-time into a singularity, for example.
Singularities are themselves curious objects, which include points where the physics of the general relativity of space deforms the more granular metrics of quantum mechanics. Unfortunately, these two master theories do not agree with certain crucial details of reality, so no one is sure what a singularity is.
Even the surrounding deformation of space and time makes a mess of our intuitions, leaving room to speculate that each black hole is a navel for a completely separate universe.
It’s not as exaggerated as it sounds. There are plenty of good reasons to think that once a collapsing observer crosses the horizon of events – a line of no return – space and time become indistinguishable from an expanding universe like ours.
This would mean that every time a star collapses to form a singularity, our Universe becomes a parent. Mazel tov!
If the PBHs differ is that they would have appeared back when our Universe had maybe about a second, a time when radiation dominated (and not much else).
With enough thrust in any area, that great concentration of light could turn the edge into a singularity. And because the conditions were already extreme, the amount of mass required would be well below that required for even the smallest stellar black holes.
Primordial black holes are interesting ideas in the desperate lack of solid evidence. Unfortunately, the smaller holes would have evaporated long ago in a puff of Hawking radiation. And anything big enough that we would certainly have noticed by now.
But there are possibilities that researchers have not yet ruled out.
In this new model, the team returned to a theory that quantum effects in empty space could create something like a vacuum bubble, providing a seed for collapse.
Their math shows that these conditions during a period of rapid inflation could reasonably create primordial black holes in a range of masses. Interestingly, some would fit in with what we would expect from dark matter.
It is an old idea that has been hit for some time, as it seems less and less likely as a candidate. If a population of these strange black holes behaves like dark matter, it will probably be only part of it.
Just to add to the skepticism, the method the team wants to use to search for these items has been tried before.
Last year, researchers used the Subaru Telescope’s Hyper Suprime-Cam to collect nearly 200 snapshots of our neighboring galaxy Andromeda over seven hours, just to see if a PBH with the mass of our moon could float.
Apart from a single “maybe”, the experiment did not find anything excessive.
But with this new model, researchers say if we wait a little longer – like about 88 hours – we could be lucky this time. Or at least rule out their prediction.
Identifying a primordial black hole of this size would provide cosmologists with an object that could help explain a range of puzzling problems. Not only could they contribute to our understanding of dark matter, but their collisions with neutron stars could explain rapid radio explosions.
You may have already seen a destruction between these light black holes in a signature gravitational wave event that had all the characteristics of a lightning-fast neutron star fusion.
As for whether these ancient black holes really harbor the babies of our own Universe, we would need a fairly revolutionary physics to confirm. But the types of black holes produced in this scenario would be exactly what we are looking for.
Fingers crossed Hyper Suppress-Cam could contribute little to the family album.
This research was published in Physical review letters.