In News:

Scientists have discovered a "black hole triple" system, which is a rare configuration in space involving one black hole and two stars.

Overview of the Discovery:

• Location: The system is located 8,000 light years away from Earth, in the constellation Cygnus.
• Key Features:
  • A black hole at the center, currently consuming a star that is spiraling very close to it.
  • A second, more distant star that orbits the black hole every 70,000 years, and another star that orbits it every 6.5 days.

What is a Black Hole Triple System?

• Black Hole and Two Stars: Unlike typical binary systems (comprising a black hole and one other object), this system contains a black hole surrounded by two stars, one nearby and one far away.
• V404 Cygni: The central black hole in the system is the V404 Cygni, one of the oldest known black holes, roughly 9 times the mass of the Sun.

Significance of the Discovery:

• Questions on Black Hole Formation: The discovery raises new questions about how black holes are formed. Traditionally, black holes are thought to form after the explosion of a massive star (supernova), but this system does not follow that model.
• New Formation Theory: Researchers suggest the black hole may have formed via a "direct collapse" process, where a star collapses into a black hole without undergoing a supernova explosion. This is referred to as a "failed supernova".
  • In a failed supernova, the star's collapse happens too quickly for the explosive outer layers to be ejected, leading to the formation of a black hole without the typical violent explosion.

Implications for Other Binary Systems:

• The black hole’s gradual consumption of one of its stars may imply that some binary black hole systems could have originally been triple systems, with one star eventually being consumed by the black hole.

Research and Collaboration:

• Study: The discovery was made by researchers at California Institute of Technology (Caltech) and Massachusetts Institute of Technology (MIT).
• Published in: The findings were published in Nature in October 2024.

Additional Context:

• Distance: The system is about 8,000 light years away, which is vast but still observable with advanced telescopes.
• Mystery of the "Failed Supernova": The concept of a failed supernova offers new insights into the life cycle of massive stars and their transformation into black holes.

Why is it in the News?

For the first time, astronomers have observed the area right at the edge of a black hole where matter stops orbiting and plunges straight in at near-light speed.

What is the Plunging Region of a Black Hole?

• The plunging region of a black hole is an area where matter ceases to orbit the celestial object and instead falls directly into its incalculable depths.
  • This phenomenon was initially predicted by Albert Einstein's groundbreaking theory of general relativity, which continues to shape our understanding of the cosmos.
• As matter approaches a black hole, it is torn apart and forms a rotating ring known as an accretion disc.
• According to general relativity, there exists an inner boundary within this disc, beyond which nothing can maintain its orbit around the black hole.
  • Instead, the material is drawn towards the black hole at nearly the speed of light, marking the beginning of the plunging region.
• This region, situated just outside the event horizon, represents the point of no return for matter falling into a black hole.
• Despite the challenges posed by studying these enigmatic structures, researchers believe that investigating plunging regions could unveil new insights into the formation and evolution of black holes.
• Additionally, these studies may offer valuable information about the fundamental properties of space-time, potentially transforming our understanding of the universe and its most mysterious inhabitants.

What is a Black Hole?

• A black hole is a celestial phenomenon that arises from the remnants of a massive star that has exhausted its nuclear fuel and undergone gravitational collapse.
• It is characterized by an unfathomably dense core, known as a singularity, which is enveloped by a boundary called the event horizon.
• The event horizon serves as a point of no return; any matter or light that crosses this boundary is irrevocably drawn towards the singularity, making it impossible to escape the immense gravitational pull.

Black holes are classified into three categories based on their size and formation process:

• Stellar-mass black holes: These form when a massive star collapses at the end of its life cycle. They typically have masses ranging from approximately five to several dozen times that of our Sun.
• Supermassive black holes: Found at the centre of most galaxies, including our own Milky Way, these colossal structures boast masses that can reach billions of times the mass of the Sun.
• Intermediate-mass black holes: With masses between those of stellar mass and supermassive black holes, these entities are thought to form through the merger of smaller black holes or the collapse of dense clusters of stars.
• Due to their extreme nature, black holes have been the subject of extensive research and fascination in the scientific community.
• The study of these enigmatic structures continues to yield invaluable insights into the fundamental principles governing our universe.

Why is it in the News?

European astronomers have made a groundbreaking discovery by identifying Gaia-BH3, a colossal black hole located just 2,000 light years away from Earth within the Milky Way, revolutionizing our comprehension of star formation.

What Is Gaia-BH3?

• Gaia-BH3, a stellar black hole in the Milky Way galaxy, has been identified as the most massive one discovered to date.
• The European Space Agency's Gaia mission detected Gaia-BH3 due to its distinctive 'wobbling' effect on a companion star orbiting it.
• Through the use of the Very Large Telescope at the European Southern Observatory in Chile's Atacama Desert and other ground-based observatories, researchers confirmed its enormous mass.
• With a mass 33 times greater than our sun, Gaia-BH3 is situated in the Aquila constellation at a distance of 1,926 light-years from Earth, earning it the title of the second-closest known black hole.
• Gaia BH1, located about 1,500 light-years away, remains the closest known black hole to Earth with a mass approximately 10 times that of our sun.
• While Gaia-BH3 holds the distinction of being the most massive stellar black hole in our galaxy, it pales in comparison to Sagittarius A*, the supermassive black hole at the Milky Way's center, which boasts a staggering mass of roughly 4 million times that of the sun.

Difference Between Stellar and Supermassive Black Holes:

• Stellar and supermassive black holes are two distinct types of cosmic phenomena, each with unique characteristics and origins.
• Stellar-mass black holes result from the gravitational collapse of a single star or the merger of two neutron stars, resulting in masses comparable to stars.
  • Their mass typically ranges from three to fifty times that of our sun.
• In contrast, supermassive black holes boast a mass exceeding 50,000 times the solar mass, often reaching into the millions or billions.
  • The formation of supermassive black holes remains a mystery to scientists, as they are too massive to have formed from a single star's collapse.
• Their consistent presence at the center of galaxies suggests a potential connection to galactic formation.
• While our understanding of these cosmic giants continues to evolve, one thing is clear: both stellar and supermassive black holes are awe-inspiring fixtures in our universe.