Ultralight Black Holes Beyond Death’s Reach: Exploring the Possibility

Ultralight Black Holes Beyond Death’s Reach: Exploring the Possibility

Key Takeaway

A new theoretical model proposes that the universe could be filled with ultralight primordial black holes that reach an equilibrium state or become naked singularities, offering a potential explanation for dark matter while evading current observational limitations.

Summary

• The new work explores the idea of primordial black holes (PBHs) as a potential candidate for dark matter, focusing on ultralight black holes.
• PBHs are hypothetical objects formed in the early universe from micro-fluctuations in matter density and spacetime.
• While most PBH candidates have been ruled out by observations, ultralight black holes could evade these constraints due to their small size and the effects of Hawking radiation.
• The paper considers three possible outcomes for ultralight black holes:
  • Complete evaporation through Hawking radiation, resulting in a brief flash of high-energy particles.
  • Reaching an equilibrium state where evaporation is prevented.
  • Forming a naked singularity, where the event horizon disappears, leaving an exposed dense mass.
• In the latter two cases, the remnants could have a net electric charge, potentially making them detectable by future neutrino detectors.
• If the remnants are electrically neutral, they would be impossible to detect directly or through their decay, making the model essentially unprovable but consistent with observations.
• The work suggests that primordial black holes cannot be entirely ruled out as a potential dark matter candidate until better observational data is available.
• The model joins the theoretical pile of possibilities for dark matter, as the search for a conclusive solution continues.

Could Ultralight Primordial Black Holes Solve the Dark Matter Mystery?

A new theoretical model proposes an intriguing idea: the universe may be full of ultralight primordial black holes. These black holes could reach a balance or turn into naked singularities. This bold theory could explain the mysterious dark matter and also avoids conflict with existing observational data.

Primordial black holes (PBHs) are theoretical objects believed to have originated early in the universe’s history. They may have formed from tiny variations in matter density and spacetime. These small black holes can vary in size from a grain of sand to the mass of a mountain. They have often been thought to be potential sources of dark matter. This is because they gather around galaxies and do not emit light.

Most PBH candidates are unlikely due to observations. These observations show that the large number of PBHs needed to explain dark matter would cause frequent microlensing flares. During these flares, PBHs pass in front of stars, making them appear brighter. Several sky surveys have looked for these flares but found none. As a result, the idea that PBHs make up dark matter has become less popular recently.

Explore the concept of ultralight black holes, a new angle on a classic theory. These hypothetical black holes are at the lighter end of the mass scale. Here, Hawking radiation becomes significant. Hawking radiation, named after the physicist Stephen Hawking, indicates that black holes emit particles and energy. This radiation leads to their eventual evaporation.

The decay rate from Hawking radiation is faster for smaller black holes. Thus, ultralight black holes might evaporate more quickly on a cosmic scale. However, our understanding of quantum gravity is not yet complete. Therefore, the precise outcome of these ultralight black holes is still unknown. This uncertainty is where the new model becomes relevant.

The paper explores three potential outcomes for ultralight black holes:

1. Complete Evaporation: The black hole radiates away entirely, culminating in a brief flash of high-energy particles. While this scenario would add to the reheating effect of the early cosmos, no such flashes have been observed, casting doubt on this possibility.
2. Equilibrium State: Some unknown mechanism prevents complete evaporation, and the black hole reaches an equilibrium state, potentially with a net electric charge.
3. Naked Singularity: Similar to the second outcome, the black hole reaches an equilibrium state, but in this case, the event horizon disappears, leaving behind an exposed dense mass known as a naked singularity, which could also carry a net electric charge.

If the last two scenarios occur, the remains of these ultralight black holes might have an electric charge. This charge would allow the next generation of neutrino detectors to possibly find them. On the other hand, if these remains lack electric charge, they would be almost impossible to detect. They wouldn’t decay into other particles, nor would they be big enough to observe directly.

An undetectable scenario may not be satisfying scientifically, but it matches current observations. It also keeps the idea that ultralight primordial black holes could be a form of dark matter viable. Until better data is collected or our understanding of quantum gravity improves, this concept remains one of many theories in the search to solve the dark matter mystery.

HASHTAGS:

#DarkMatter, #PrimordialBlackHoles, #HawkingRadiation, #UltralightBlackHoles, #QuantumGravity, #Astrophysics, #CosmicMysterySolution, #NakedSingularities, #NeutrinoDetectors, #TheoryOfEverything #Ultralight Black Holes

Source: arXiv Link: Read the paper