Astronomers have obtained their most detailed observation to date of two black holes merging, offering fresh confirmation of theories first proposed by Albert Einstein and Stephen Hawking about the nature of space, time and gravity.
The event, which occurred 1.3 billion light-years away in a galaxy beyond the Milky Way, involved two massive black holes, one 34 times the mass of the sun and the other 32 times.
Orbiting each other at nearly the speed of light, they collided in a fraction of a second to form a single black hole about 63 times the sun’s mass, spinning at roughly 100 revolutions per second.
The merger unleashed gravitational waves, ripples in space-time, carrying energy equivalent to the destruction of three sun-sized stars. These waves were detected on January 14 at the U.S. National Science Foundation’s Laser Interferometer Gravitational-Wave Observatory (LIGO) sites in Washington and Louisiana.
Thanks to major technological upgrades since the first gravitational wave detection in 2015, scientists observed the event with four times greater precision.
“Thanks to Albert Einstein, we know that space and time are intertwined and are best thought of as facets of a single entity, space-time,” said astrophysicist Maximiliano Isi of Columbia University and the Flatiron Institute, a leader of the study published Wednesday in Physical Review Letters.
The team analyzed the frequencies of the gravitational waves, comparing them to the “ringing of a bell,” to study the properties of the black holes before and after the collision. Their findings supported a key hypothesis by the late Stephen Hawking: that the total surface area of black holes can never decrease.
In this case, the two black holes’ combined event horizons covered about 93,000 square miles (240,000 square km), while the merged black hole’s surface area expanded to roughly 155,000 square miles (400,000 square km).
“This is the first time we have been able to make this measurement so precisely, and it’s exciting to have direct experimental confirmation of such an important idea about the behavior of black holes,” said astrophysicist Will Farr of Stony Brook University and the Flatiron Institute.
The observations also bolstered Einstein’s theory of general relativity, showing that black holes are “simple” objects defined only by their mass and spin, as mathematician Roy Kerr first outlined in 1963.
According to Caltech astrophysicist Katerina Chatziioannou, the dramatic event unfolded in mere moments.
The black holes spiraled together for about 200 milliseconds, followed by a signal lasting only 10 milliseconds from the newly formed black hole, a fleeting window that has offered scientists their clearest view yet of one of the universe’s most violent phenomena.
Source: Reuters
Written By Rodney Mbua
