Jump to content

Have We Detected a Gravitational Wave Signal from a Black Hole Moon?

Avi Loeb Medium
 Share

Recommended Posts

Avi Loeb Medium Newbie

Avi Loeb Medium

Posted
Posted
1*NkT-gaKuwbdjSMLdmXXrHQ.jpeg
An artist’s illustration of the collision of the protoplanet Theia with Earth (left) that led to the formation of the Moon. (Image credit: Hernán Cañellas)

A giant impact of a Mars-size proto-planet named Theia with proto-Earth, 4.5 billion years ago, may have ejected debris that coalesced to form our Moon. Computer simulations support this giant impact hypothesis, as discussed here.

Could a moon form through a similar process when two neutron stars collide?

Dense star clusters, known as globular clusters, contain of order a million stars and are known to have stellar remnants segregated near their centers. These remnants include stellar-mass black holes and neutron stars. They are typically more massive than the background stars and hence settle towards the cluster center through a gravitational segregation process resembling the separation of heavy dust particles from air molecules under the influence of the Earth’s gravity. Near the cluster center these remnants find each other, creating pairs of black holes that coalesce through the emission of gravitational waves. This natural process could explain the origin of many of the gravitational wave sources detected by the LIGO-Virgo-KAGRA (LVK) collaboration over the past decade, as originally proposed here.

The cores of globular clusters are known to contain an abundant population of neutron stars which appear as pulsars or X-ray sources with a mass of up to twice the mass of the Sun (as discussed recently here). These neutron stars, remnants from core collapse of massive stars, have a mass density of an atomic nucleus and a characteristic size of a city, about 12 kilometers (as discussed here).

The dense core of a globular cluster can lead to the formation of pairs of black holes or neutron stars but also to three-body systems that are dynamically unstable, and can result in a head-on collision between two neutron stars under rare circumstances (as discussed here).

When two neutron stars collide head-on, their merger is expected to lead to a black hole carrying most of their combined masses. However, just as in the collision between Thea and Earth, a fraction of the mass might be ejected as debris that coalesces to form a moon made of neutron star matter.

Equilibrium configurations of stable neutron stars exist down to 0.09 of the mass of the Sun (as discussed here). Therefore, the debris from a head-on collision between two neutron stars could potentially lead to the formation of a central black hole or neutron star accompanied by a low-mass neutron-star moon. As a result of the emission of gravitational waves, the moon will ultimately merge with the central object. The lifetime of the system depends on the initial separation of the moon from the central object as well as their masses. An alternative channel for creating a black hole moon is from the core collapse of a single progenitor star to a black hole and a debris disk that coalesces into a neutron star moon, as discussed here.

On November 12, 2025, the LVK collaboration reported the detection of a gravitational wave signal from a compact merger candidate named S251112cm (as reported here). This event is statistically compelling due to its relatively low False Alarm Rate, estimated at about 1 per 6.2 years (as noted here). The source luminosity distance is estimated to be in the local Universe, measuring about 300 million light years (93 ± 27 Mpc), but a search for an electromagnetic counterpart did not yield a detection (as reported here). The analysis of the gravitational wave signal implies that the source chirp mass falls predominantly in the range of 0.1 to 0.87 solar masses, implying a sub-solar mass object at the 99% confidence. The more massive object could be in the range of 1–3.5 solar masses, based on Figure 1 here. The inference of a low-mass object raises the possibility that S251112cm may have been produced by the coalescence of a neutron star moon and an order of magnitude more massive companion in the form of a black hole or a neutron star.

Our own Moon might also crash back on Earth. This would not be the result of gravitational wave emission but rather its drag on the envelope of the Sun once it expands as a red giant to engulf the Earth-Moon system (as discussed here).

Some moons are doomed to crash back on their birth place, just like adults settling back to their childhood home.

ABOUT THE AUTHOR

1*LE3Xlzc3hNG5VDAGlDP8KQ.jpeg
(Image Credit: Chris Michel, National Academy of Sciences, 2023)

Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024.

Professional website:

https://lweb.cfa.harvard.edu/~loeb/

Social media:

https://avi-loeb.medium.com/
https://www.youtube.com/@ProfessorAviLoeb

https://open.spotify.com/show/1zhndXkvSY2b8FdjspFpCd
https://x.com/ProfAviLoeb

stat?event=post.clientViewed&referrerSou

View the full article

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
 Share
Go to topic listing

  • Similar Topics

    • SpaceObserver
      Would A Yellowstone Super-Eruption Have Asteroid-Like Impacts?
      By SpaceObserver
      In a recent segment on NewsNation, Dr. Kayla Iacovino discussed the potential catastrophic effects of a super-eruption from the Yellowstone supervolcano. One striking point made was that such an event could have consequences akin to those of a massive asteroid impact. This comparison raises important questions about our preparedness and understanding of volcanic hazards.
      Dr. Iacovino explained that Yellowstone is home to one of the largest volcanic systems on the planet, and an eruption could bring about widespread devastation, affecting air quality, climate, and even agricultural systems. The scale of the potential damage is daunting. Using historical data on previous eruptions, such as the last major activity around 640,000 years ago, scientists can estimate the far-reaching effects on both local and global scales.
      The discussion led by Jesse Weber emphasizes how critical it is to separate science fact from science fiction, particularly when discussing such profound geological threats. Many people might dismiss the supervolcano's potential for future activity, often viewing it as a distant concern, but the reality is that these systems are constantly monitored by geologists and volcanologists.
      One of the key challenges in understanding supervolcanoes is the unpredictability of their eruptions. Unlike asteroids, which can be tracked and predicted to a degree, volcanic activity can be much harder to foresee. While scientists can monitor signs of unrest, such as earthquakes and gas emissions, predicting the exact timing and magnitude of an eruption remains complex. This uncertainty is a significant limitation in our current scientific understanding.
      Moreover, the comparison to asteroid impacts brings up fascinating avenues for discussion regarding disaster preparedness. If we can clearly articulate the threats posed by Yellowstone, perhaps we can begin to develop more robust strategies for crisis response and even public education on this topic. The dialogue around such geological hazards is often overshadowed by more immediate concerns, yet the potential for widespread disruption makes it a critical issue.
      So, considering the implications of Dr. Iacovino's insights, how should we balance between monitoring these geological threats and investing in public awareness regarding their potential impact? Understanding the science is one thing, but engaging the public with accurate information is another challenge altogether. What steps can we take to ensure that awareness translates into effective preparedness?
    • CosmicSignals
      Researchers Propose Searching The Moon For Microscopic Technosignatures
      By CosmicSignals
      A recent study presents a novel idea for searching for signs of extraterrestrial intelligence: examining lunar regolith for microscopic engineered particles. Led by Dr. Lewis Pinault from the SETI Institute, this research outlines a quantitative framework for investigating whether tiny, durable particles from past technological civilizations could have accumulated on the Moon over billions of years.
      The researchers suggest that instead of focusing solely on radio or laser signals from potential alien civilizations, we might find evidence of their existence in the form of microscopic debris. This approach is intriguing because the Moon, lacking an atmosphere, flowing water, or tectonic activity, has preserved material from across the Solar System for approximately four billion years. This stability makes it a unique archive of the Milky Way’s history.
      Dr. Pinault points out that the Moon has been continuously collecting dust and materials, much of which could predate the Moon itself. The hope is that if advanced civilizations produce durable microscopic debris—either as a direct result of their activities or as unintended byproducts—some of that material could be embedded in the lunar soil.
      The study emphasizes that while it does not claim to have found extraterrestrial technosignatures, it lays out a practical observational framework for future lunar sample-return missions. The authors propose that by carefully analyzing about one cubic meter of lunar regolith with modern microscopy and AI-assisted imaging, we could begin to determine the presence of artificial materials that might hint at past technological life.
      The methodology outlined involves using advanced techniques such as tomography and spectroscopy to sift through lunar soil. Such techniques could help establish limits on the amount of artificial material produced by technological civilizations throughout the history of the Galaxy. This information could then shed light on how many technologically capable civilizations might have existed in our Milky Way.
      One aspect that stands out in this proposal is how it reframes our search for extraterrestrial intelligence. Traditionally, SETI has concentrated on signals sent from other civilizations, but looking for physical remnants could reveal a broader narrative of intelligent life in the cosmos. It raises questions about how we define evidence of alien life and what forms that evidence might take.
      However, the study does have limitations. It does not provide evidence of such particles existing on the Moon, nor does it guarantee that future missions will find them. The success of this approach depends heavily on the next steps taken by lunar exploration missions, which will need to incorporate these new methodologies into their sampling and analysis processes.
      As we delve deeper into this line of inquiry, it poses a fascinating question: if we were to find signs of past civilizations on the Moon, what would that mean for our understanding of life in the universe? Could we be on the verge of discovering that we are not alone, but rather part of a much larger historical tapestry of intelligent life? The implications could be profound not only for astrobiology but for humanity's place within the cosmos.
    • CosmicSignals
      New Framework For Searching The Moon For Microscopic Technosignatures
      By CosmicSignals
      A recent study suggests that the Moon could be a key site for searching for microscopic technosignatures—tiny, engineered particles left behind by technological civilizations. This idea shifts the focus from traditional methods like radio signal detection to examining lunar regolith, which has been collecting material from space for billions of years. Lead researcher Dr. Lewis Pinault from the SETI Institute outlines a framework for detecting these potential remnants of past civilizations.
      One striking detail is that, unlike Earth, the Moon has no atmosphere or flowing water to erode ancient material. This makes the lunar surface a stable archive, allowing for the possibility that microscopic debris from advanced civilizations could have survived the passage of time. The study emphasizes the potential for discovering evidence that might have been overlooked in other searches.
      The researchers propose that if advanced civilizations create durable microscopic debris, this material could become embedded in the Moon's surface. Over a four-billion-year period, the lunar regolith has collected dust and particles from the Solar System and beyond, creating a unique historical record. The study does not claim to have found these technosignatures but sets the groundwork for future lunar missions to search for them.
      Using modern microscopy and AI-assisted imaging techniques, scientists could analyze one cubic meter of lunar regolith to establish limits on the amount of artificial material present. This could provide insights into the number of technologically capable civilizations that may have existed in our galaxy. The framework proposed could pave the way for future missions to test these hypotheses, potentially revolutionizing our understanding of life beyond Earth.
      The notion that the Moon could hold remnants of ancient technologies raises intriguing questions about our own search for extraterrestrial life. If tiny particles from lost civilizations have made their way to the Moon, what other secrets might our celestial neighbor hold? This study urges us to reconsider how we approach the search for life beyond our planet by expanding our focus to include the Moon as a site of potential discovery.
      As the lunar surface continues to be explored, the potential for uncovering these technosignatures invites further investigation. What might we learn about the history of civilizations, both terrestrial and extraterrestrial? The challenge lies in devising methods to distinguish natural lunar materials from those that may be artificial in origin.
      Given the exciting possibilities ahead, how might future lunar sample-return missions adapt their methods to search specifically for these microscopic traces of technology? The answers could significantly impact our understanding of life in the universe.
    • SpaceObserver
      UFO Disclosure: Whistleblower Claims And Black Triangle Sightings
      By SpaceObserver
      I just came across a fascinating video from NewsNation that compiles some recent UFO disclosure claims, including notable whistleblower testimonies and reports of black triangle sightings. One of the highlights discusses a piece of metal said to have been recovered by the Soviet Union, which has sparked quite a bit of debate on its origin and significance.
      The video presents several allegations from whistleblowers who claim to have inside knowledge about government investigations into UFOs. These testimonies often touch on the mysterious nature of black triangle sightings, which have been reported by both military personnel and civilians alike. Black triangles are often described as large, silent craft that glide through the sky, and they have been a topic of intrigue for decades. The claims surrounding them are often met with skepticism, yet they continue to draw attention, especially in light of recent government hearings.
      Another intriguing aspect mentioned in the video is the latest UFO file release, which is part of an ongoing effort by the government to be more transparent about its investigations. This aligns with the recent push for greater accountability within government agencies regarding UAP (Unidentified Aerial Phenomena) sightings and encounters. Many hope that as more information becomes available, it will help clarify some of the uncertainties surrounding these phenomena.
      The disputed metal piece from the Soviet era adds another layer of complexity. If indeed it has ties to extraterrestrial technology, it could potentially change our understanding of both history and current UAP phenomena. However, the lack of verifiable evidence surrounding this claim raises important questions about its authenticity and the motivations behind its disclosure. It seems like the more we dig, the more questions arise rather than answers.
      Overall, the video encourages viewers to consider the implications of these claims and the broader context of government transparency regarding UFOs. As someone interested in both space exploration and the potential for extraterrestrial life, I find the intersection of scientific inquiry and government investigation particularly compelling. It’s a reminder that while we seek answers about life beyond Earth, there are still many unresolved mysteries within our own skies.
      What do you think the government should focus on next regarding UAP investigations and disclosures? Are we ready for full transparency, or is there still too much at stake?
    • MysteryFiles
      Another Wave of Military UAP Encounters in 2026?
      By MysteryFiles
      It seems like we've hit another peak in military encounters with UAPs this year. Just last month, a Navy pilot reported a close encounter during a training exercise off the coast of San Diego. The pilot described an object that was able to dart around at incredible speeds, seemingly defying the laws of aerodynamics as we understand them. This brings back memories of those infamous 2004 Nimitz encounters; it's fascinating to see similar reports bubbling up again.
      What’s particularly interesting is how the military seems more open to discussing these incidents now. After years of secrecy, the recent congressional hearings have shed some light on the UAP task force's findings. I wonder if this shift in openness reflects a growing pressure to address these phenomena, especially with more pilots coming forward with their experiences.
      Another angle to consider is the technology aspect. The fact that these UAPs can perform maneuvers that our current technology can’t replicate raises questions. Are we looking at advanced foreign technology, or is there something else at play here? The recent reports mention radar tracking and visual confirmations from multiple sources, yet there’s still so much ambiguity around what these crafts actually are.
      I also can't help but think about the implications for future military training and tactics. If these UAPs are indeed some advanced technology, how do we prepare our forces to respond to encounters? The military has a historical framework for dealing with conventional threats, but UAPs present a whole new category of unknowns.
      I'd love to hear if anyone else has been following the series of encounters this year. Are there any particular cases that stand out to you? Or do you think that the increased reporting might just be a coincidence in timing? It feels like we’re on the cusp of a deeper understanding, but the specifics remain frustratingly elusive.
×
×
  • Create New...