Testing Einstein’s Theory of General Relativity From the Shadows and Collisions of Black Holes

Binary Black Holes About to Collide

Artist’s impression of binary black holes about to collide. Credit: Mark Myers, OzGrav-Swinburne University

General relativity, Einstein’s theory of gravity, is best tested at its most extreme — close to the event horizon of a black hole. This regime is accessible through observations of shadows of supermassive black holes and gravitational waves — ripples in the fabric of our Universe from colliding stellar-mass black holes. For the first time, scientists from the ARC Centre of Excellence for Gravitational Wave Discovery (OzGrav), the Event Horizon Telescope (EHT), and the LIGO Scientific Collaboration, have outlined a consistent approach to exploring deviations from Einstein’s general theory of relativity in these two different observations. This research, published in Physical Review D, confirms that Einstein’s theory accurately describes current observations of black holes, from the smallest to the largest.
One of the hallmark predictions from general relativity is the existence of black holes. The theory provides a specific description of a black hole’s effect on the fabric of space-time: a four-dimensional mesh which encodes how objects move through space and time. Known as the Kerr metric, this prediction can be related to the bending of light around a black hole, or the orbital motion of binary black holes. In this study, the deviations from the Kerr metric were linked to features in these black hole observations. 
In 2019, the Event Horizon Telescope generated silhouette images of the black hole at the center of the galaxy M87, with a mass several billion times that of our Sun. The angular size of the shadow is related to the mass of the black hole, its distance from Earth, and possible deviations from general relativity’s prediction. These deviations can be calculated from the scientific data, including previous measurements of the black hole’s mass and distance.

Meanwhile, since 2015 the LIGO and Virgo gravitational-wave observatories have been detecting gravitational waves from merging stellar mass black holes. By measuring the gravitational waves from the colliding black holes, scientists can explore the mysterious nature and metrics of the black holes. This study focussed on deviations from general relativity that appear as slight changes to the pitch and intensity of the gravitational waves, before the two black holes collide and merge.
Combining the measurements of the shadow of the supermassive black hole in M87 and gravitational waves from a couple of binary black hole detections, called GW170608 and GW190924, the researchers found no evidence for deviations from general relativity. Co-author of the study and OzGrav research assistant Ethan Payne (Australian National University) explained that the two measurements provided similar, consistent constraints. “Different sizes of black holes may help break the complementary behavior seen here between EHT and LIGO/Virgo observations,” said Payne. “This study lays the groundwork for future measurements of deviations from the Kerr metric.”

Reference: “Probing the Black Hole Metric. I. Black Hole Shadows and Binary Black-Hole Inspirals” by Dimitrios Psaltis, Colm Talbot, Ethan Payne and Ilya Mandel, 18 May 2021, Physical Review D.
DOI: 10.1103/PhysRevD.103.104036
arXiv: 2012.02117

Written by OzGrav research assistant Ethan Payne, the Australian National University.

5 Comments on "Testing Einstein’s Theory of General Relativity From the Shadows and Collisions of Black Holes"

  1. Bibhutibhusanpatel | May 1, 2021 at 7:48 am | Reply

    The result of experiment must nòt differ in mrasured valuès of mass and dìstance of super massive black hole at the centrè of galaxy M87.Say,we measured curvature at time instants t1 and t2,nowfind the curvature by integrating between two limits t2 and t1,the result is r.So difference in force of attraction between two
    instants t1 and t2 of the supermassive black hole of M87 is is simply change in mass for two ponts of time of observation.We know the change ìn distance of the same from earth for two instants of time r.

  2. Bibhutibhusanpatel | May 1, 2021 at 8:05 am | Reply

    The Theory of relativity has another form to describe phenomena for galaxies.This is-
    1.The distance between two instants of time is fond by integral of distance with referrence to time.
    2.Mass is variable for these two instants of time.
    Thanks to the auther for right and bold representation

  3. Bibhutibhusanpatel | May 1, 2021 at 8:18 am | Reply

    Highly prospective discovery following right measurements,cited for galaxy M87 and some more,added with certain conclusion for Theory of Relativity having limit.

  4. Deviations from the GR theory can only be attributed to the deviations in positions of the objects due to the precession of the force diagram depicted.

  5. Theory of Relativity in Indian scriptures

    There are innumerable examples of Einstein theory of relativity in ancient Indian scriptures. Modern Scientists are awestruck on seeing the strikingly similar concepts in Indian scriptures while others are surprised to find high-fi scientific concepts in Indians scriptures written thousands of years ago. Many Indian scientists consider Indian scriptures as world past history and are researching Vedas and other ancient literatures for more scientific discoveries.
    Before I give the practical examples of Einstein “Theory of relativity” in Indian scriptures, it is very important for us to understand what Einstein “Theory of relativity” exactly is.

    Practical Example of Theory of Relativity

    Suppose you are kidnapped and carried in a private smooth vehicle travelling at a speed of 100 kilometers per hour. Now you are not aware that you are travelling along with the vehicle at a speed of 100 kilometers per hour. If you look out the window, you will feel that your vehicle is stationary and the person standing outside is moving at a speed of 100 kilometers per hour. But the person standing on a road feels that he is stationary and your vehicle is moving at a speed at 100 kilometers per hour. Another stationary person might feel that your vehicle is stationary and the road is moving at a speed of 100 kilometers per hour.

    This situation is very similar to our observance that the earth is stationary and the sun & moon moves from east to west.
    Einstein theory of relativity is very well explained in the below YouTube video. Please understand it nicely.

    Short conclusion of Einstein theory of relativity
    1) Nothing travels faster than light.
    2) It is not possible to say which object is stationary and which object is moving.
    3) Every observer is correct in thinking that he is stationary and everything else is moving around.
    4) Time is relative to your motion. If you travel faster, time moves slowly. If you travel at speed of light, clock stops ticking and so, even if you travel for one year, you will be of the same age you were when you started travelling at speed of light.

    Suppose you are 28 years old and your brother is 26 years old. Now you start travelling from earth to space at speed of light for twenty human years. When you return back to earth, you find that you are still young and 28 years old but your brother has grown old and is 46 years old. You will be surprised to know that your younger brother has became elder and you have become the younger one.

    This concept of relativity has been proved by American scientist and astronauts travelling in space on their spacecrafts. Even when the astronauts travel in spaceships for years, they feel like travelling for only few days.

    Theory of relativity in Indian scriptures

    Now, I am going to depict the above theoretical concept in ancient Indian stories.

    To understand the story, below is the concept you must apprehend.

    According to Indian scriptures, Brahma is the creator of this universe and the planet where he resides is called as “Brahma-Lok”. His creation aspect is repetitive in nature where there is a Satya yuga (Golden age) which spans for 1.728 million years, followed by Treta yuga(Silver age) spanning 1.296 million years, followed by Dwapar yuga (Bronze age) spanning 864 million years followed by Kali yuga(Dark age) spanning 432000 million years. These four yugas are repeated 71 times to form one manvantara. Manvantara is repeated fourteen times to form Half kalpa, meaning One day of Lord brahma. Another half kalpa is night of Lord Brahma.

    Below image will help you in better understanding the Indian concept of time.


    Story of Kakudmi in Brahmalok

    In satya yuga(Golden age), there lived a benevolent and courageous king called Kakudmi. He had a very beautiful daughter named revati, endowed with auspicious and mystical qualities. King Kakudmi was not able to find a suitable match for her in the entire earth and decides to travel to Brahmalok (Which exist millions of light years away from earth). When they arrived at brahma lok, Lord Brahma was listening to a musical performance by celestial Dancers. King kakudmi waited patiently for sometime till the musical performance was finished. After the musical performance when Lord Brahma asked the king for his problem, he said “I am not able to find a suitable match for my daughter ‘Revati’”. Then Lord Brahma smiles and explains that time runs differently on different planes of existence. Your few minutes in my celestial planets are equivalent to many yugas on earth. Brahma said by the time you came and stayed here, already 27 Manvantara have passed. “O King, all your ministers, wives, kinsmen, father etc, all those whom you have accepted as your sweetheart has swept away in the course of time. Today, nobody on earth knows about you or your descendants”. Shocked and surprised, king looks for a solution. Then Brahma says “If you start now, by the time you reach earth, you will be in Dwapar yuga of 28 Manvantara. There you can marry your daughter to Balaram, the avatar of Sheshnath, Lord Vishnu serpent. And You will be granted Moksha(Salvation) by none other than lord Krishna, avatar of lord Vishnu for that yuga.”

    Now this story is very well explained in Indian television serial “Shri Krishna”. Search for the video on youtube.

    The video is in Hindi without English subtitles. I wanted to upload this video in English but I can’t because of copyright issues. Since more than 65% of my visitors are from US and other non-Hindi speaking countries, I will give second to second translation of the above video.
    King kakudmi: “In the entire earth, I did not see a single suitable match for my daughter ‘Revati’. So, I have come here to ask you, on which celestial planet, I shall find a suitable match for her and who will be her husband.”
    Lord Brahma: “You will find a husband for her at the earth itself.”
    King kakudmi:”But O lord, I didn’t find a single king or prince suitable for her on earth.”
    Lord Brahma: “The Kings and princes whom you are talking about, no longer exist at this moment”
    King kakudmi:”O Lord, I didn’t understand.”
    Lord Brahma: “Son, Speed of time on earth and my celestial planet (Brahmalok) is different. On earth, speed of time is so fast that in one day of Brahms loka, many yugas on earth have passed. During your stay on Brahma loka, three yugas have passed on earth. O king, don’t waste time any more. Go to earth as early as possible. Till you reach there, Dwapar yuga would have ended. At that time, Lord Sheshnath would incarnate in a human form. He along with the ever-pervading god Lord krishna may be playing game (illusions) on earth. Your daughter Revati in reality is a wife of sheshnath. Under the blessings of Devi nagalakshmi, she has incarnated on earth to serve her husband sheshnath. ”
    kakudmi pays respect to her incarnated daughter Revati.
    Lord Brahma “By giving your daughter to sheshnath, not only you will be free from your responsibility but also will you get salvation from lord Krishna. You will get the happiness of staying forever on the foots of ever pervading god.”
    King kakudmi and Daughter revati pay their respects to lord Brahma
    Travelling at speed greater than light, Narada, Celestial son of Brahma announces this news to lord Krishna.
    Lord Krishna: “You news is very auspicious. I am very happy.”
    Sage Narada: “Narayan Narayan(Narayan is name of lord vishnu). (Looking through his divine perception) narada tells lord Krishna about the travelling of various celestial planets by Princess Revati and father Kakudmi. They will be reaching on earth soon. So, prepare for welcoming them. I am leaving.”
    King kakudmi: “Daughter, we have reached earth But how will we find Lord sheshnath in this big earth.”
    Revati: “Hey father, your words are like asking how to find light in darkness. Light shows the path to the source. Look at the earth carefully. You will find the lord yourself.”
    Revati: “Look at that Daughter. Look!!! Let’s go. We should reach fast.”

    In the next video, you can see the marriage of Revati with sheshnath.

    In this video, there is an interesting concept. In this video, you can see that Size of Revati and king kakudmi are very huge. Srimag bhagavatam tells that there is degrading level of species in each yuga. In satya yuga, all species are very large in size. In Treta yuga, species are relatively small compared to Satya yuga and so on with next yugas. This also explains why the animals were bigger millions of years ago and the findings of ancient giant human skeletons. There’re few more scientific concept in the above video but that shall be a separate topic of discussion but I would like to see if you are able to find any scientific concepts in this video.

    Now the next story shows how Brahma was fooled in his own illusion.

    Brahma vimohana Lila:

    Once Lord Krishna was playing with cows and friends at Vrindavan. Brahma didn’t believe that the little kid Krishna is an incarnation of lord Vishnu. He decides to prove it to his spy. Brahma steals all the lord Krishna friends including cows and takes them to Brahma lok. When lord Krishna realizes the test of Brahma, he decides to teach Brahma a lesson. Through his mystical power, Lord Krishna creates identical copies of his friends and cows. When truti( fraction of a second) passes on brahma loka, Brahma realizes that one year has passed on earth. Brahma decides to investigate on the happenings of vrindavan and was bewildered to see Krishna playing with his friends and calves just like before. Seeing the boys and calves simultaneously both on earth and Brahma lok, Brahma realizes that Krishna is none other than lord Vishnu. Brahma also sees other Brahmas which explains the scientific concept of multiple universe, one Brahma for each universe. Krishna explains the concept of multiple universes to lord Brahma. Brahma then apologizes and sends all lord Krishna friend’s back to earth.

    This story is very well explained in the below video. This video is in English and music is copied from “lord of the rings” movie.
    The Stealing of the Boys and Calves by Brahma


    The Sanskrit word used in this story is truti. According to Vedic astronomy, truti means 1/33750 of a second.

    Muchukund fight with demons in Indra loka

    In treta yuga, When demons attacked Deva loka(Celestial planet few layers above earth), Indra(Lord of heaven) requested valiant warriors from other planets to fight against demons. King Muchukund from earth joined indra to fight against the demon. Their fight lasted for one year and ultimately, indra and other deities defeated the demons. After the battle, Indra asked Muchukund for a boon. King Muchukund said “I want to go back to earth to meet my family”. In a grim voice, Indra said “You fought here for only one year but millions of years have passed on earth and no one on earth remembers you now”.

    See the video of this story along with the translation

    Fight with demons
    Indra praises Muchukund and asks for a boon.
    Muchukund: “I don’t need any boon. I have everything on earth courtesy of the blessings of my father and ancestors. I have a huge kingdom where all the comforts are waiting for me. I have so much happiness on earth that I don’t need anything else. So, please do me a favor by allowing me to go to earth. I have fulfilled my responsibility of serving you. You don’t need me anymore. Also, Lord shiva son has agreed to become commander in chief of your army. So, your future is safe now and hence, I request you to send me on earth where my kinsmen and wives are waiting for me”
    Indra: I cannot give you this permission
    Muchukund: “Cannot give??..Why can’t you?… Was there anything lacking in my servitude?”….
    Indra in a grim voice: “No No..I am very happy with your service …..but …..”
    Muchukund in a angry voice: “But What?…. But What Lord?…. But What Lord?….”
    Indra: “King muchukund, No one from your family Exist on earth now”
    muchukund: “No one exists there now. What are you saying? Did my enemies destroyed my kingdom?”
    Indra: “No Emperor Muchukund. Nothing like that happened. This happened because of speed of time.”
    Muchukund: “Speed of time ….I didn’t understand O lord”.
    Indra: “King, You don’t know about speed of time. Speed of time is different in heaven and earth. Speed of time is very fast on earth. So, by the time you stayed here, one yuga has passed on earth. So much time has passed that nor your son is there nor your wives nor your citizens. On the contrary, No one knows about your clan ‘Ishvaku’.”
    muchukund: “How did this happen my lord?”
    Indra: “This is speed of time, O king. In this world, only god is indestructible else every born being has to die. Even the deities here have to die. On our time, Time god will destroy us. When I die, somebody else will take my place. So, I request you to forget about the ones who no longer exist and it is my wish that you ask for the pleasures you are looking for. I will grant you all such pleasures and comforts. I want to give you a boon. Wealth, sex, happiness, fame or anything else. I can give you anything except Moksha(Salvation) because the power of giving salvation is only with lord shiva and lord Vishnu. Ask? Ask For boon, O king? Ask For boon, O king?”

    There may be many such more stories but as of now I have not studied all Indian scriptures. So, these are the only stories I am aware of. In Indian scriptures, science is explained through stories. So, instead of believing Indian scriptures as mythology, better start decoding it for absolute truth.

    I will conclude this article with the following sentences from the Bhagavat Purana which explains the relativity of time:

    “… One’s life endures for only one hundred years, in terms of the times in the different planets… Eternal time is certainly the controller of different dimensions, from that of the atom up to the super-divisions of the duration of Brahmâ’s life; but, nevertheless, it is controlled by the Supreme. Time can control only those who are body conscious, even up to the Satyaloka or the other higher planets of the universe.”

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