Tuesday05 November 2024
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The Mystery of the Last Parsecs: What Really Happens During Black Hole Mergers (Photo)

One of the most violent events in space is the collision and merger of two matter-devouring entities. However, this phenomenon still holds many mysteries.
Загадка последнего парсека: что действительно происходит при слиянии черных дыр (фото)

Scientists understand that black holes, the most dense objects in the universe that consume matter and do not release it, can merge to form a new black hole. What exactly happens inside these black holes during the merging process remains unclear, and researchers can only speculate. However, the mechanics of this process are known, as reported by Space.

Approaching Black Holes and Loss of Orbital Energy

Imagine two black holes orbiting each other along long paths. They may have formed after the death of a binary star or randomly approached each other in the depths of space. For a merger to occur, the black holes must get closer, which involves losing a significant amount of orbital energy.

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Initially, the loss of orbital energy occurs due to the interaction of black holes with surrounding objects: interstellar gas, stars, or planets. All these objects interact with the black hole through gravity. Sometimes they fall into the black hole, while other times they can escape from the strong gravitational grasp of the matter devourer. This interaction results in a portion of the black hole's orbital energy being lost.

Once the black holes are close enough, a different process takes over. The black holes distort spacetime as they orbit each other, creating gravitational waves that emanate from them, resembling ripples on a water surface when a boat sails through it. When black holes are in close proximity, these gravitational waves contribute to the loss of orbital energy.

The Last Parsecs Problem

However, there is a mystery that puzzles astrophysicists, known as the last parsec problem. Simulations have shown that gravitational interactions with the surrounding environment can bring black holes to within about 1 parsec (3.26 light-years) of each other over a long period. Yet, at this distance, there is simply not enough matter for orbital energy to dissipate. On the other hand, at that same distance, gravitational waves are too weak and would take billions of years—longer than the age of the universe—to extract orbital energy.

Regardless of what occurs, ultimately, the black holes get close enough for gravitational waves to genuinely extract substantial energy from the system. At this moment, the black holes have only a few seconds left before they completely merge.

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At such close distances, the black holes begin to distort each other. Black holes lack a surface; instead, they possess an event horizon, an invisible boundary beyond which matter cannot escape the black hole. However, the shape of the event horizon depends not only on the black hole itself but also on the geometry of spacetime around it. Thus, as the black holes start the merging process, their event horizons elongate and stretch towards each other.

How Does the Complete Merging of Two Black Holes Occur?

What happens next has only been understood through simulations. Milliseconds before the collision, each black hole emits a thin, tiny tunnel from its event horizon towards its companion. These tunnels meet and merge, forming a bridge between the two black holes that connects them. The bridge quickly expands, the event horizons join, and in an instant, the black holes merge into one large object.

What occurs inside black holes remains a mystery. The center of a black hole is known as a singularity, a point of infinite density. It is at this location that all known laws of physics cease to function. Simulations indicate that singularities quickly find each other, rotate around one another briefly, and then merge. However, what truly happens there is unknown to astrophysicists.

Why is the New Black Hole Less Massive than its Predecessors?

Strangely, the new black hole has a mass that is less than the total mass of the black holes that created it. A few years ago, scientists discovered that a black hole with a mass 36 times that of the Sun merged with another black hole that had a mass 30 times greater than our star. Ultimately, the new black hole ended up with a mass only 63 times that of the Sun.

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Astrophysicists believe that the missing mass was converted into energy in the form of gravitational waves. To put this in perspective, it is akin to converting three Suns into pure energy. When black holes merge, they release more energy than every star in the universe combined.