Integral satellite disproves dark matter origin for mystery radiation
July 22, 2009
The left-hand panel shows the glow of 511 keV gamma rays coming from the annihilation of electrons by their antimatter counterparts, the positrons. The map shows the entire sky, with the galactic centre at the middle. The emission can be seen extending towards the right-hand side of the map. The right-hand panel shows the distribution of hard low mass X-ray binary stars. This stellar population has a distribution that matches the extent of the 511 keV map. Credits: ESA/ Integral/ MPE (G. Weidenspointner et al.)
(PhysOrg.com) -- A team of researchers working with data from ESA’s Integral gamma-ray observatory has disproved theories that some form of dark matter explains mysterious radiation in the Milky Way.
That this radiation exists has been known since the 1970s, and several theories have been proposed to explain it. Integral’s unprecedented spectral and spatial resolution showed that it strongly peaks towards the centre of the Galaxy, with an asymmetry along the Galactic disc.
Several researchers have invoked a variety of dark matter to explain Integral’s observations. Dark matter is thought to exist throughout the Universe - undetectable matter that differs from the normal material that makes up stars, planets and us. It is also believed to be present within and around the Milky Way, in the form of a halo.
The recent study has found that the ‘positrons’ fuelling the radiation are not produced from dark matter but from an entirely different, and much less mysterious, source: massive stars explode and leave behind radioactive elements that decay into lighter particles, including positrons, the antimatter counterparts of electrons.
This is an artist’s impression of ESA’s orbiting gamma-ray observatory, Integral. Credits: ESA
The reasoning behind the original hypothesis was that positrons, being electrically charged, would be affected by magnetic fields and thus would not be able to travel far. As the radiation was observed in places that did not match the known distribution of stars, dark matter was invoked as an alternative for the origin of the positrons.But the recent finding by a team of astronomers led by Richard Lingenfelter at the University of California at San Diego, proves otherwise. The astronomers show that the positrons formed by radioactive decay of elements left behind after explosions of massive stars are, in fact, able to travel great distances, with many leaving the thin Galactic disc.
Taking this into account, dark matter is no longer required to explain what Integral saw. A better understanding of how positrons behave has explained the mysterious radiation in our Galaxy.
More information:
Reference publication
Lingenfelter, R.E., Higdon, J.C. Rothschild, R.E., "Is There a Dark Matter Signal in the Galactic Positron Annihilation Radiation?", Physical Review Letters, Volume 103, Issue 3, 031301, 2009. DOI:10.1103/PhysRevLett.103.031301
Related publications
Higdon, J. C., Lingenfelter, R. E., Rothschild, R. E., "The Galactic Positron Annihilation Radiation and the Propagation of Positrons in the Interstellar MediDOI:10.1088/0004-637Xical Journal, Volume 698, Issue 1, pp. 350-379, 2009. DOI:10.1088/0004-637X/698/1/350
WeidensDOI:10.1038/nature06490An asymmetric distribution of positrons in the Galactic disk revealed by gamma-rayDOI:10.1016/j.newar.2008.06.019, 2008a. DOI:10.1038/nature06490
Weidenspointner, G., et al., "Positron astronomy with SPI/INTEGRAL", New Astronomy Reviews, Volume 52, Issues 7-10, pp 454-456, 2008b. DOI:10.1016/j.newar.2008.06.019
Provided by ESA
Jan 09, 2008 |
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There was another recent news report from UC-San Diego that came to the same conclusion:
Ordinary matter doing ordinary things produced the radiation that had been attributed to imaginary dark matter.
This is indeed encouraging!
With kind regards,
Oliver K. Manuel
http://www.omatumr.com
In this case, maybe that is the case, although further analysis needs to be done, to be conclusive. However, there are many other 'mysteries' which need to be resolved and dark matter still is a strong possibility. Would someone here be willing to present a better explanation than dark matter?
Steinhardt, Turok, Randall, Sundrum et al.
Is that a citation for a single paper? Google Scholar shows many papers written by some of those authors, but none written by all of them. Could you link to a specific article, or articles? I'm not going to read all of the hundred or so papers written by all those guys. ;-)
Absolutely! By AWT...
No. It was meant as a listing of some of those who are known to already having presented a "better" explanation than dark matter. ("Better" of course not being necessarily a purely scientific measure.)
Yes. Steinhardt and Turok have been working together on the Ekpyrotic Model and its successor, the Cyclic Model. Randall and Sundrum have introduced another cosmological model involving branes and higher dimensions. Both models are IMHO a lot more elegant than the dominant standard cosmological model.
Neither can I although I'd like to.
For beginners I recommend two Wikipedia articles:
http://en.wikiped...ic_model
http://en.wikiped...-Sundrum
The evidence we have of the gamma ray phenomenon is %u2026 the gamma ray phenomenon. That is, we have detected and mapped the source (or group of contiguous sources) of gamma ray emissions from the direction of the centre of the galaxy. Plus, thanks to Integral's high resolution observations, we have found a group of 'remnant stars' in the area at the centre of the same galaxy. The group remnant stars are distributed about the centre of the galaxy in a manner that forms a shape, (as observed from earth today), that is similar to that of the source(s) of the gamma ray phenomenon.
Has Integral (or any other experiment) detected the 'positron debris' or witnessed any of the 'matter/antimatter annihilations' from the proposed explosions of massive stars?
Has the age of the gamma rays been compared to that of the light (of lower energy emissions) from the remnant stars?
More philosophically, could it be said that 'dark matter' has been explained in this theoretical model as 'normal matter' that has been transformed by events that have become 'hidden in time'?
I know (from that which has been reported in popular fiction and the science journals upon which it was based) that CERN, and possibly other labs around the world, have 'captured' and stored securely small amounts of anti-matter, and that some experimental annihilations have been witnessed and recorded. Gamma radiation, (as one group of frequencies of light, amongst the many, including visible light), is product of such events. Perhaps it would be better to say that an immense range or spectra of light, (visible, invisible and extremely high energy) is produced by each annihilation.
But %u2026 is annihilation the only natural occurring event that could produce the gamma radiation, (emission of light, described often in this specific phenomenon as a 'glow'), that could account for the observations in that area of the sky, or is this article simply reporting the relief felt by many theoretical mathematicians and cosmologists that a more acceptable, (slightly more traditional; even more relational), theory has been proposed for the inconclusively-explained phenomenon?
Fifty years from now the shape formed by those remnant stars as they orbit around the galactic centre will obviously change, but the pattern of distribution of the proposed particulate debris (from the (simultaneous?) massive star explosions) will be much less affected by the orbit from which they originate. Perhaps the current observation will be inverted, and the majority of remnant stars will appear on the left of the galactic centre while the majority of the gamma ray glow will still appear of the right. Would the new theory fit so well if that configuration was observed by Integral today?
Last thought: the entire cosmos is smoke and mirrors, and we are trying to discern where the magician's hands have been. In this scenario, one of the hands may be the black hole that resides in the centre of those Integral observations.
Ray Cherry, there is zero (0) probability (P), P = 0.0000000, that cosmologists and astrophysicists will ever comprehend the origin of radiation coming from the galactic centre if they continue to ignore experimental evidence that nuclear dissociation, rather than fusion, powers the Sun and the cosmos [See: "The sun's origin, composition and source of energy", in Lunar and Planetary Science XXIX, Abstract 1041, available as 1041-pdf from Lunar and Planetary Institute, Houston, TX (CD-ROM, 2001); "Attraction and repulsion of nucleons: Sources of stellar energy", Journal of Fusion Energy 19, 93-98 (2001); "Nuclear systematics: III. The source of solar luminosity", Journal of Radio-analytical and Nuclear Chemistry 252, 3-7 (2002); "The standard solar model versus experimental observations" in Proceedings of the Third International Conference on Beyond Standard Model Physics - BEYOND 2002 (IOP, Bristol, editor: H. V. Klapdor-Kleingrothaus) pp. 307-316 (2003); "Neutron repulsion confirmed as energy source", Journal of Fusion Energy 20, 197-201 (2003); etc.]
With kind regards,
Oliver K. Manuel
http://www.omatumr.com
Neither of those articles suggest any alternative to dark matter; nor do they even mention galactic rotation rates (the main evidence for dark matter.)
The Cyclic Model is just the theory that each Big Bang is followed by a Big Crunch and then another Big Bang. Pretty basic stuff. Dark matter is consistent with that model; in fact it's usually a part of the model.
Your wiki article says that the Steinhardt-Turok model describes dark energy as a repulsive force between colliding branes; but it doesn't refute dark energy (or even mention dark matter). Not that dark energy and dark matter have anything to do with each other anyway.
The article on the Randall-Sundrum models also discusses branes and dark energy, but again with no reference to dark matter. Were you confusing dark matter with dark energy?
Anyway, I'm still seeing no alternative explanation for the strange rotational rates of galaxies, or gravitational lensing which exceeds the mass of visible matter, or unexplained gas distributions, or any of the other evidence for dark matter.
You know, I don't understand why people consider dark matter to be so strange anyway -- "dark matter" simply means "matter which we can't see." Is it really so hard to believe that there's a lot of matter in the universe that we can't see? I mean, our deep-space sensing abilities are pretty limited... And, yeah, I know it's not just a bunch of space rocks (it's nonbaryonic), but it *could* be largely made up of neutrinos.
Damon Hastings does not "understand why people consider dark matter to be so strange anyway -- "dark matter" simply means "matter which we can't see."
Is it really so hard to believe that there's a lot of matter in the universe that we can't see?"
During the Dark Ages, it would have seemed reasonable to to believe that there's a lot of matter in the universe that we can't see.
There is no longer any "mystery radiation," "mysterious cosmic explosions," nor "mysteriously vanishing solar neutrinos" for those who study the 3,000 nuclear mass data points [ http://www.omatum...Data.htm ] that describe the ground state of every atom in the visible universe [See: Neutron repulsion confirmed as energy source, Journal of Fusion Energy 20 (2001) pages 197-201: http://tinyurl.com/38un57 ]
With kind regards,
Oliver K. Manuel