Blackhole has been one of the intrigued topics for scientists from across the globe. It was April last year when the world saw the first photo of a black hole, one of the star-devouring monsters scattered throughout the Universe and obscured by impenetrable shields of gravity.

Colliding black holes aren't always as evenly matched as scientists expected and these collisions have puzzled over for a year.

On April 12, 2019, gravitational wave detectors picked up a signal of space-time ripples caused by colliding black holes — which in and of itself has gone from groundbreaking to nearly mundane over the past five years. But as scientists studied the detection more closely, they realized that it didn't match the signals they have seen so far.

Instead of two evenly matched black holes, the new detection seemed to be triggered by a lopsided merger in which one black hole was three or four times more massive than the other.

The detection of Gravitational-wave in a collision between two black holes of substantially different masses has made astronomers excited. 

The discovery was announced by the Scientists affiliated with the Laser Interferometer Gravitational-wave Observatory (LIGO) at the online meeting of the American Physical Society. 

The collision was called GW 190412 and it was something scientists have never seen before writes astronomer Christopher Berry of Northwestern University and the LIGO Collaboration in a blog post. 

Rather than two roughly equal-mass black holes between 20 and 40 times the mass of the Sun, GW 190412 was produced by a wildly uneven binary.

A suite of tests performed on GW190412 indicates consistency with Einstein’s general theory of relativity. 

To know more about it click here to read- LIGO Scientific Collaboration and Virgo Collaboration or watch the video given below...

Black holes, phenomenally dense celestial entities, are extraordinarily difficult to observe despite their great mass. A black hole's event horizon is the point of no return beyond which anything - stars, planets, gas, dust and all forms of electromagnetic radiation - get swallowed into oblivion.

"This is a huge day in astrophysics," said U.S. National Science Foundation Director France Córdova. "We're seeing the unseeable."

The fact that black holes do not allow light to escape makes viewing them difficult. The scientists look for a ring of light - disrupted matter and radiation circling at the tremendous speed at the edge of the event horizon - around a region of darkness representing the actual black hole. This is known as the black hole's shadow or silhouette.