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An Antimatter Cloud Around Galactic Center

Although I had planned to push straight on to look at instrumentation for a true interstellar mission (using Mike Gruntman’s landmark paper on the topic), I want to revise that schedule because of the recently announced antimatter news. We’ll return to the instrumentation issue on Monday, including the tricky question of how a probe designed to reach 400 AU can make effective measurements given its speed (75 km/s in the best case scenario Gruntman looks at). Because that question just gets trickier as speeds ramp up, it’s a major one for planning.

But on to antimatter, a cloud of which has been known to exist around the galactic center since the 1970s, when balloon-based gamma-ray detectors first located it. Gamma rays are significant in terms of antimatter because electrons encountering positrons (their antimatter equivalent) annihilate each other, with their mass converted into high energy gamma rays. So the cloud’s presence is well established. The question since its detection is what could have caused it.

Now a new paper in Nature may offer an answer, noting the asymmetric distribution of the antimatter cloud, which extends further on one side of galactic center than on the other. We’re talking about a cloud some 10,000 light years across, generating the energy of 10,000 Suns. The research team used data from the European Space Agency’s Integral satellite (INTErnational Gamma-Ray Astrophysics Laboratory) to detect the asymmetry. Their paper notes that it matches the distribution of a certain type of binary star systems, the latter thought to contain neutron stars and black holes.

Antimatter cloud around galactic center

Image: Integral mapped the glow of 511 keV gamma rays from electron-positron annihilation. The map shows the whole sky, with the galactic center in the middle. The emission extends to the right. Credit: ESA/Integral/MPE/G. Weidenspointner.

Are these binary stars the cause of the antimatter cloud? They’re what’s known as ‘hard’ low-mass X-ray binaries. The mechanism at play is that gas from a low-mass star spirals into a black hole or neutron star nearby, with high-energy (hard) X-rays resulting. That and the relative similarity between the distributions of cloud and stars makes the case that the binaries are producing these interesting positrons. In fact, says lead author Georg Weidenspointer (Max Planck Institute for Extraterrestrial Physics), “Simple estimates suggest that about half and possibly all the antimatter is coming from X-ray binaries.”

Of course, what comes immediately to mind at this end is James Bickford’s interesting work on antimatter collection here in the Solar System. As we saw in several earlier posts, Bickford has been advocating collection strategies that would mine the antimatter being formed naturally not only near the Earth but also in abundance further out in the Solar System, especially around Saturn. So the idea of antimatter farming again comes to the front with this renewed reminder that the exotic stuff occurs as a result of astrophysical processes and not just in particle accelerators.

Not that we’re able to tap a cloud like this one, so vast and so much further from Earth. But on a theoretical level, it’s useful to learn more about antimatter production even while we’re discovering the limitations in our existing theories. For the questions the antimatter cloud poses are themselves vast. The low-mass binaries seem associated with the antimatter cloud but we lack knowledge of how they could produce enough positrons to account for it. That probably targets particle jets as the necessary area for investigation, something NASA’s GLAST (Gamma-ray Large Area Space Telescope) may be able to shed further light on. And GLAST is helpfully ready for a 2008 launch.

The paper is Weidenspointner et al., “An asymmetric distribution of positrons in the Galactic disk revealed by big gamma-rays,” Nature 451 (10 January 2008), pp. 159-162 (abstract).

Comments on this entry are closed.

  • James M. Essig January 11, 2008, 23:40

    This is an awesome discovery. Evidently, very large amounts of antimatter are contained in this cloud thus perhaps pointing to new physics at work. I must say that I have never heard of the proposed naturally occuring antimatter collecting methods at locations within the vicinity of Earth and around Saturn. If we can collect large quantities of antimatter and store it in dense solid form such as in the form of antihydrogen ice, positroium atoms, and the like, we might perhaps observe some assymetrical electromagnetic, or perhaps even some novel gravitational or inertial effects of the bulk antimatter that are not detectable on the microscopic particle level.

    The finding of this huge antimatter cloud just goes to show all the more the existence of vaste quantities of varied natural resources available for future humanity to tap into as we venture out into interstellar space to ply the depths of the Milky Way Galaxy.



  • george scaglione January 12, 2008, 10:16

    jim yes fantastic! potentially great!!! but how do you “mine” it? the deposits in our solar system would be difficult enough to get to.but around the galactic center!? a thosand times more difficult! great argument actually for my ideas that we should use traversable wormholes.something we should seriously think about how to go about developing! my opinion. the very best one and all your friend george

  • Administrator January 12, 2008, 13:27

    Jim, if you missed the antimatter collection articles, I ran a three-part study of James Bickford’s work on this within the last couple of months. Just use the search box with ‘bickford’ as the search term and you can pull these up.

  • george scaglione January 13, 2008, 12:56

    paul it is so good to know that people are already thinking about anti matter collection! thank you yet again! your friend george

  • djlactin January 13, 2008, 23:47

    just an idle tangent:

    what is the density of antimatter in the cloud?
    i’d think that a ‘normal matter’ item (like a collector) would be at great risk of colliding with a stray positron and making quite a spectacle of himself.

  • forrest noble January 14, 2008, 15:14

    George, How do you “mine it”? very carefully with robotic craft!!!!!!!!!!!!!!!!!!!!

    Jim, me too. I’ve never read about any quantitative positrons in our neighborhood.

    Paul, thanks for the heads-up. Interesting article and detail.

    djlactin, It can’t be very dense. As soon as it might try to contract a bit some electrons would radiate in and the fireworks would go off providing seemingly more expansion pressure.

    Other possible explanations could be high-energy electons interacting with a stationary dust cloud– these high-speed impacts could also cause gamma rays.

    But we all like, what they now consider the most likely model, the positron rocket fuel depot model.

    your friend forrest

  • george scaglione January 15, 2008, 9:03

    yes forrest,lol that is exactly how you’d have to mine it!!! thank you george

  • ljk January 16, 2008, 1:02

    The Mystery of the Missing Antimatter

    Helen R. Quinn & Yossi Nir

    To read the entire book description or a sample chapter, please visit:


    In the first fractions of a second after the Big Bang lingers a question at the heart of our very existence: why does the universe contain matter but almost no antimatter? The laws of physics tell us that equal amounts of matter and antimatter were produced in the early universe–but then, something odd happened. Matter won out over antimatter; had it not, the universe today would be dark and barren. But how and when did this occur? Helen Quinn and Yossi Nir guide readers into the very heart of this mystery–and along the way offer an exhilarating grand tour of cutting-edge physics.

    “The standard model of particle physics is Quinn and Nir’s arena for discussing one of its inadequacies: it has yet to answer why in the trillionths of a second after the big bang, there was a tiny numerical superiority of matter over antimatter; if there was not, atoms would not have formed. Addressing nonscientists, the authors describe the nature of this intriguing problem…[This book] will challenge yet reward readers with understanding of a fascinating subject at the frontier of science.”–Gilbert Taylor, Booklist

    Cloth | $29.95 / £17.95 | ISBN: 978-0-691-13309-6

  • forrest noble January 17, 2008, 1:42

    ljk, sounds interesting but I bet the answer to almost every question including this one is much simpler than current theory asserts. In my theory, no kidding, electrons are more readily produced than positrons although both are known to be relatively stable. If they are produced in pairs the positrons more often appear just as virtual particles and do not stabalize as often.

    Protons are very stable and anti-protons are less stable (not stable) paticles in an open field like neutrons. Very simple answers to the question of why there is primarily just matter– if these statements are true. If you want to know why, according to theory, this is true, e-mail me. The answer is equally as simple but a little longer, but not too long I promise.

    forrest underscore forrest at netzero dot net

    your friend forrest

  • ljk March 24, 2008, 9:49

    The FLAMINGOS-2 Galactic Center Survey

    Authors: Stephen S. Eikenberry (University of Florida)

    (Submitted on 20 Mar 2008)

    Abstract: Upon commissioning on Gemini South, FLAMINGOS-2 will be one of the most powerful wide-field near-infrared imagers and multi-object spectrographs ever built for use on 8-meter-class telescopes. In order to take best advantage of the strengths of FLAMINGOS-2 early in its life cycle, the instrument team has proposed to use 21 nights of Gemini guaranteed time in 3 surveys — the FLAMINGOS-2 Early Science Surveys (F2ESS). The F2ESS will encompass 3 corresponding science themes — the Galactic Center, galaxy evolution, and star formation. In this paper, I review the design performance and status of FLAMINGOS-2, and describe the planned FLAMINGOS-2 Galactic Center Survey.

    Comments: To be published in Proceedings of “A Population Explosion: The Nature and Evolution of X-ray Binaries in Diverse Environments”, 28 Oct – 2 Nov, St. Pete Beach, FL; eds. R.M. Bandyopadhyay, S. Wachter, D. Gelino, C.R. Gelino; AIP Conference Proceedings Series

    Subjects: Astrophysics (astro-ph)

    Cite as: arXiv:0803.3084v1 [astro-ph]

    Submission history

    From: Reba M. Bandyopadhyay [view email]

    [v1] Thu, 20 Mar 2008 21:22:34 GMT (12kb)


  • ljk July 1, 2008, 12:05

    Cosmic antimatter: models and observational bounds

    Authors: A.D. Dolgov

    (Submitted on 27 Jun 2008)

    Abstract: A model which leads to abundant antimatter objects in the Galaxy (anti-clouds, anti-stars, etc) is presented. Observational manifestations are analyzed. In particular, the model allows for all cosmological dark matter to be made out of compact baryonic and antibaryonic objects.

    Comments: 19 pages, 3 figures, presented at Rencontre de Physique de la Vallee d’Aoste, La Thuile, February 24 – March 1, 2008

    Subjects: High Energy Physics – Phenomenology (hep-ph); Astrophysics (astro-ph)

    Cite as: arXiv:0806.4554v1 [hep-ph]

    Submission history

    From: Alexander Dolgov [view email]

    [v1] Fri, 27 Jun 2008 15:56:15 GMT (405kb)


  • bj thorndyke April 5, 2009, 20:15

    hello, i hope my idea is,nt insulting to persons with high intelegence, but i love the cosmos, and wondered that when matter, and antimatter colided and matter just won , did the energy from the antimatter convert to dark energy , and really won the , to form the greater power. thank you bj thorndyke.

  • Administrator April 6, 2009, 8:38

    bj, we know too little about dark energy to be able to say yet what caused it, so I suppose the idea that antimatter is implicated can’t be ruled out. But it does seem that we are dealing with a force that is currently beyond the understanding of physics, so you can bet that dark energy will be the focus of much study in coming decades. A Nobel Prize is surely out there for whomever figures it out!

  • ljk August 15, 2009, 23:40

    In Search of Antimatter Galaxies‏

    NASA Science News for August 14, 2009

    A powerful cosmic ray detector to be installed on the International Space Station will search for antimatter galaxies and other exotic phenomena in the Universe.

    FULL STORY at: