Here\u2019s what you\u2019ll learn when you read this story:<\/p>\n
Studying black holes is immensely difficult, but with gravitational wave detection, astrophysicists do have a way to directly analyze these mysterious objects.<\/p>\n
A new study details the \u201cclearest gravitational wave signal to date\u201d from two colliding black holes that formed a final black hole clocking in at 63 solar masses.<\/p>\n
Differentiating frequencies (or tones) associated with the collision from the final black hole itself, scientists confirmed two long-standing black hole theories.<\/p>\n
Black holes\u2014whether in their stellar, intermediate, or supermassive sizes\u2014are among the most fascinating objects in the universe<\/a>. They also happen to be some of the hardest to study. After all, how do you analyze an object with such massive gravity that not even light can escape?<\/p>\n Well, in 2015, the Laser Interferometer Gravitational-Wave Observatory (LIGO<\/a>) provided a compelling option by detecting the very first gravitational wave, one that happened to be the result of two black holes colliding long ago. For such a cataclysmic cosmic event, the resulting \u201cchirp\u201d of the collision doesn\u2019t sound like much to the uninitiated<\/a>. But to astrophysicists studying black holes, the ringing frequencies of these mergers\u2014both leading up to and following the collision\u2014can provide an immense amount of information.<\/p>\n Due to technological limitations at the time, records from the original 2015 merger didn\u2019t contain enough data to confirm two prominent black hole theories: The idea that black holes could be described by just mass and spin, and Stephen Hawking\u2019s<\/a> area theorem\u2014that a black hole\u2019s event horizon can only grow over time.<\/p>\n After a decade of improving detection technologies and methods, scientists finally have \u201can exquisitely detailed view of the signal both before and after the black hole<\/a> merger,\u201d Maximiliano Isi, an astrophysicist at the Flatiron Institute\u2019s Center for Computational Astrophysics, said in a press statement<\/a>. Isi, along with dozens of other members of the LIGO-Virgo-KAGRA Collaborations, published a study in the journal Physical Review Letters<\/a> detailing this new high-fidelity \u201cringing\u201d data on black hole mergers. This study builds upon Isi\u2019s previous work<\/a>, which tried to isolate these deep-space tones using the 2015 data.<\/p>\n \u201cThis is the clearest view yet of the nature of black holes,\u201d Isi said. \u201cWe\u2019ve found some of the strongest evidence yet that astrophysical black holes are the black holes predicted from Albert Einstein\u2019s theory of general relativity.\u201d<\/p>\n In this new paper, scientists analyzed another black hole merger (GW250114), which formed a black hole with a mass of 63 Suns<\/a> and spun at a stunning 100 revolutions per second. Being the \u201cclearest gravitational wave signal to date,\u201d according to the Max-Planck-Gesellschaft<\/a>, the authors were able to actually \u201chear\u201d both black holes growing as they merged into one, confirming both Hawking\u2019s area theorem and the Kerr metric<\/a> (describing black holes using only mass and spin).<\/p>\n Confirmation of Hawking\u2019s area theorem draws parallels to the Second Law of Thermodynamics<\/a>, which states that entropy must increase or remain constant over time. The authors suggest that by probing the thermodynamics of black holes, we could learn more about about even bigger cosmic mysteries\u2014most notably, quantum gravity.<\/p>\n \u201cIt\u2019s really profound that the size of a black hole\u2019s event horizon behaves like entropy<\/a>,\u201d Isi said in a press statement. \u201cIt has very deep theoretical implications and means that some aspects of black holes can be used to mathematically probe the true nature of space and time.\u201d<\/p>\n In the next decade, gravitational wave detectors will be 10 times more sensitive than they are today, and plans are already in motion to build LIGO\u2019s successor, known as the Laser Interferometer Space Antenna (LISA<\/a>), which will investigate gravitational waves at even lower frequencies (including those originating from supermassive black holes).<\/p>\n