The universe is indeed home to a lot of mysteries that await to be uncovered.
Only 5% of the universe is something we are aware of. An unknown world of new particles and forces lie within the remaining 95%, waiting to be discovered. The cosmos as we know it now has been fashioned by these unidentified particles and forces, even though they are currently unseen to us.
Among these mysterious components of our universe are black holes. But first, let’s define what black holes are. In space, a black hole is a region where gravity is so strong that even light cannot escape. Because stuff has been compressed into a small area, gravity is extremely powerful. When a star is dying, this may occur.
The idea of black holes has existed for a very long time, dating back to the theory of Einstein of general relativity that when a massive star dies, it leaves a small and dense core. The equations demonstrated that if the core’s mass is more than roughly three times that of the Sun, the force of gravity will outweigh all other forces and result in the creation of a black hole.
Originally, black holes were believed to appear in two radically different sizes: stellar black holes or the remnants of massive stars 10 to 24 times as massive as the Sun and supermassive black holes which are almost billions of times as massive as the Sun. These supermassive black holes are believed to exist virtually at the center of all large galaxies.
Historically, astronomers have rejected the idea of mid-sized black holes but recent evidence proved otherwise. Just as they begin to understand the existence of big black holes, astrophysicists have also been able to discover the notion of black holes smaller than the stellar black holes—these are called micro black holes. They are also known as mini black holes or quantum mechanical black holes that are smaller than stellar mass and have been first introduced in 1971 by Stephen Hawking.
How are micro-black holes produced? The concentration of mass or energy inside the matching Schwarzschild radius is necessary for the creation of a black hole. Hawking separately proposed the idea that, soon after the Big Bang, the Universe was sufficiently crowded for every particular region of space to fit within its own Schwarzschild radius. This idea was first put forth by Zel’dovich and Novikov. However, given the uniform mass distribution and quick expansion at the time, the Universe was able to avoid collapsing into a singularity. This does not, however, completely rule out the possibility that black holes of different diameters could have formed locally.
But just how tiny are these micro black holes? Tiny, as used in this context, is about equivalent to a couple of billion tons, or the mass of a minor asteroid, or one-billionth of one-billionth of the mass of the sun. Astronomers believe that the universe is peppered with these numerous tiny black holes which may have been created when the universe was extremely young and heated. Some areas of space were denser than others because this primordial substance was not spread equally throughout the early cosmos.
However, the argument lies on whether these micro black holes still survived roughly after 14 billion years after the big explosion. Astrophysicists have several takes on it: Stephen Hawking famously asserted that black holes can lose mass eventually after emitting ‘elementary particles’. A process called ‘Hawking radiation is the cause of the shrinking of a black hole and its eventual evaporation. While scientists believe that this process may be inapplicable to the black holes whose mass is as large as the sun, it may be applicable to the smaller-sized black holes.
This makes it even more different to create a direct observation or gather sufficient evidence of micro black holes as we would with stellar or supermassive black holes which create significant and observable impacts with neighboring stars as a result of accretion.
Following the notion of Hawking radiation, within the course of the universe, any primordial black hole with a suitably low mass will evaporate to a level close to that of the Planck mass. These tiny black holes radiate stuff when they do this. This can be roughly explained as pairs of virtual particles emerging from the vacuum near the event horizon, one of which is caught and the other of which escapes the area around the black hole.
The black hole ultimately loses mass as a result due to the conservation of energy. Black hole thermodynamics states that as a black hole loses mass, it gets hotter and evaporates more quickly until it gets closer to the Planck mass.
A recent study reveals that tiny black holes may be traveling through Earth regularly, acting like cosmic ghosts. The new hypothesis disproves end-of-the-world scenarios in which the planet is sucked up by massive black holes created by atom-smashing accelerators like the Large Hadron Collider.
Indeed, black holes could be menacing. But what would occur if a black hole the size of an asteroid collided with Earth? Disaster, in a word. The black hole would almost instantly rip through the surface of our planet, but due to its gravitational interaction with Earth, it would immediately start to slow down. Any atom, molecule, or person that crosses the black hole’s event horizon—the region beyond which nothing, not even light, can escape—would instantly vanish from the visible world and never be seen again.
A more optimistic scenario would be for it to leave through the opposite side of Earth, leaving the survivors to tidy up the debris. In the worst case, the black hole would crash into the center of our world, where its gravitational pull would be strong enough to enable it to start consuming matter. It would eventually eat up the entire world.
Also, in the unlikely possibility, our planet would heat up if it came into contact with a black hole which is not exactly a good picture. The black hole would accrete matter as it passed past Earth, and this accretion would produce heat. The energy released by the collision of an asteroid-mass black hole would be comparable to that of a kilometer-wide asteroid or a dinosaur-killer event intensity.
Fortunately, the calculations indicate that there is very little possibility of a micro-black hole colliding with Earth’s core. Black holes move too quickly. In fact, based on scientific data, if black hole collisions were to happen, they would occur once every billion years.