Discovering Dark Matter: New Clue From Mysterious Clouds Circling Spinning Black Holes

Artist's Conception of Black Hole

Gravitational waves are cosmic ripples in the fabric of space and time that emanate from catastrophic events in space, like collisions of black holes and neutron stars — the collapsed cores of massive supergiant stars. Extremely sensitive gravitational-wave detectors on Earth, like the Advanced LIGO and Virgo detectors, have successfully observed dozens of gravitational-wave signals, and they’ve also been used to search for dark matter: a hypothetical form of matter thought to account for approximately 85% of all matter in the Universe. Dark matter may be composed of particles that do not absorb, reflect, or emit light, so they cannot be detected by observing electromagnetic radiation. Dark matter is material that cannot be seen directly, but we know that dark matter exists because of the effect it has on objects that we can observe directly.

Ultralight boson particles are a new type of subatomic particle that scientists have put forward as compelling dark matter candidates. However, these ultralight particles are difficult to detect because they have extremely small mass and rarely interact with other matter — which is one of the key properties that dark matter seems to have.

Lilli Sun

Dr. Lilli Sun is on the hunt for boson clouds – a key contender for dark matter. Credit: Tracey Nearmy/ANU

The detection of gravitational waves provides a new approach to detecting these extremely light boson particles using gravity. Scientists theorize that if there are certain ultralight boson particles near a rapidly spinning black hole, the extreme gravity field causes the particles to be trapped around the black hole, creating a cloud around the black hole. This phenomenon can generate gravitational waves over a very long lifetime. By searching for these gravitational-wave signals, scientists can finally discover these elusive boson particles, if they do exist, and possibly crack the code of dark matter or rule out the existence of some types of the proposed particles. 

In a recent international study in the LIGO-Virgo-KAGRA collaboration, with OzGrav Associate Investigator Dr. Lilli Sun from the Australian National University being one of the leading researchers, a team of scientists carried out the very first all-sky search tailored for these predicted gravitational wave signals from boson clouds around rapidly spinning black holes. 

“Gravitational-wave science opened a completely new window to study fundamental physics. It provides not only direct information about mysterious compact objects in the Universe, like black holes and neutron stars, but also allows us to look for new particles and dark matter,” says Dr. Sun.

Although a signal was not detected, the team of researchers was able to draw valuable conclusions about the possible presence of these clouds in our Galaxy. In the analysis, they also took into consideration that the strength of a gravitational wave signal depends on the age of the boson cloud:  the boson cloud shrinks as it loses energy by sending out gravitational waves, so the strength of the gravitational wave signal would decrease as the cloud ages. 

“We learned that a particular type of boson clouds younger than 1000 years is not likely to exist anywhere in our Galaxy, while such clouds that are up to 10 million years old are not likely to exist within about 3260 light-years from Earth,” says Dr. Sun.

“Future gravitational wave detectors will certainly open more possibilities. We will be able to reach deeper into the Universe and discover more insights about these particles.”

For more on this research see Ghostly Boson Clouds Could Solve the Mystery of Dark Matter.

Reference: “All-sky search for gravitational wave emission from scalar boson clouds around spinning black holes in LIGO O3 data” by The LIGO Scientific Collaboration, the Virgo Collaboration, the KAGRA Collaboration: R. Abbott, H. Abe, F. Acernese, K. Ackley, N. Adhikari, R. X. Adhikari, V. K. Adkins, V. B. Adya, C. Affeldt, D. Agarwal, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, P. Ajith, T. Akutsu, S. Albanesi, R. A. Alfaidi, A. Allocca, P. A. Altin, A. Amato, C. Anand, S. Anand, A. Ananyeva, S. B. Anderson, W. G. Anderson, M. Ando, T. Andrade, N. Andres, M. Andrés-Carcasona, T. Andrić, S. V. Angelova, S. Ansoldi, J. M. Antelis, S. Antier, T. Apostolatos, E. Z. Appavuravther, S. Appert, S. K. Apple, K. Arai, A. Araya, M. C. Araya, J. S. Areeda, M. Arène, N. Aritomi, N. Arnaud, M. Arogeti, S. M. Aronson, K. G. Arun, H. Asada, Y. Asali, G. Ashton, Y. Aso, M. Assiduo, S. Assis de Souza Melo, S. M. Aston, P. Astone, F. Aubin, K. AultONeal, C. Austin, S. Babak, F. Badaracco, M. K. M. Bader, C. Badger, S. Bae, Y. Bae, A. M. Baer, S. Bagnasco, Y. Bai, J. Baird, R. Bajpai, T. Baka, M. Ball, G. Ballardin, S. W. Ballmer, A. Balsamo, G. Baltus, S. Banagiri, B. Banerjee, D. Bankar, J. C. Barayoga, C. Barbieri, B. C. Barish, D. Barker, P. Barneo, F. Barone, B. Barr, L. Barsotti, M. Barsuglia, D. Barta, J. Bartlett, M. A. Barton, I. Bartos, S. Basak, R. Bassiri et al., 30 November 2021, Astrophysics > High Energy Astrophysical Phenomena.

6 Comments on "Discovering Dark Matter: New Clue From Mysterious Clouds Circling Spinning Black Holes"

  1. … “Dark matter may be composed of particles that do not absorb, reflect, or emit light”
    So, what if there is no light left in that matter to emit, or if it is an anti light, like a anti photon…

  2. @xABBAAA there is no anti-photon. Since the photon has no electric charge it is effectively its own antiparticle.

    • … yeah, I know but why?
      The physics doesn’t answer that question and it will not provide any reasonable answer. But could it be that the dark matter is not existing at all?
      Or could it be that it is just a deviation in the space time that is caused by some particles that exist in different 1/7 or 1/3 thingy not 1/2 etc thingy.
      Then one would have the gravity as touching point, but why…
      Or is could be a strange thing that we don’t understand like anti protons wiz in from the past or it could be …
      Yeah, the anti-protons are not observed yet, but why and if there would be some of them wouldn’t they kick the photons and then we would not see them, but then there should be some glow or bling… or is that a anti Symmetrie…

  3. Howard Jeffrey Bender, Ph.D. | December 13, 2021 at 5:36 am | Reply

    In the first place, ultralight boson particles are speculative in themselves. In the second place, gravitational waves from extremely massive sources may be caused by other things, too.

    Another possibility, from a view of String Theory, is that Dark Matter appears to us as an effect of string/anti-string annihilations. As you may know, quantum mechanics requires that strings must be formed as pairs in the quantum foam – a string and an anti-string – that immediately annihilate each other. Quantum mechanics also requires both the string and anti-string to be surrounded by “jitters” that reduce their monstrous vibrating energies. What if this jitter remains for a fraction of an instant after their string/anti-string annihilations? This temporary jitter would be seen by us as matter, via E=mc2, for that instant before it too returns to the foam. That’s why we never see it – the “mass” lasts only for that instant but is repeated over and over and over, all over. Specifics on this can be found in my YouTube, Dark Matter – A String Theory Way at

  4. Dean Winchester, PhD, JD, MS, MA and CEO | December 14, 2021 at 5:20 pm | Reply

    Dear Ozgrav,
    Please be more careful in your use of language. “Dark matter is material that cannot be seen directly, but we know that dark matter exists because of the effect it has on objects that we can observe directly.”
    We do not “KNOW” that it exists. “Dark matter” is one of several reasonable solutions to effects that are observed to deviate from current theory. Applying Occam’s Razor PROPERLY (i.e. we are NOT looking for the “simplest” solution, we are looking for the solution which requires the FEWEST ASSUMPTIONS) would actually lead one to the conclusion that MOND is a better fit. But then you cannot write pseudo-scientific click-bait with that, can you?
    Dark matter requires a LOT of assumptions. MOND requires one. “New physics” requires one. “Hand of Zeus” requires one…though Zeus can be eliminated as (a) nonfalsifiable and (b) obviously wrong, as the flying spaghetti monster is clearly a better fit and better tasting.

    So to quite the smartest man in the universe, “Stay scientific, Jerry.”

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