Astrophysicists have an concept that could assist to resolve two mysteries: the explanation for the weird abundance of super-high-energy radiation capturing from the middle of our galaxy and the identification of invisible stuff known as dark matter that has perplexed the world since its discovery some 50 years in the past.And the concept has a super-cool identify: gravity portals. The thought goes, when two dark matter particles (no matter they’re) get sucked into considered one of these portals, they obliterate one another and spit out shockingly robust gamma rays. This line of pondering can probably clarify why the galactic middle — the place dense clusters of dark matter are thought to lurk — is stuffed with gamma rays; and it could make clear how the dark matter behaves and may sometimes work together with the traditional matter of our universe.Related: The 11 largest unanswered questions on dark matterWhat dark matter has to beMore than 80% of the matter in our universe is of a kind unknown to the usual mannequin of particle physics. Scientists name it “dark matter,” as a result of it doesn’t work together with gentle. The first trace of dark matter’s existence got here within the 1970s, when astronomer Vera Rubin seen that galaxies had been rotating far too rapidly — with out an extra, hidden supply of gravity, they need to have torn themselves aside eons in the past.For a long time, astronomers did not know in the event that they wanted to alter their understanding of gravity, add extra regular-but-really-dim matter to the universe, or embody a model new ingredient. But yr after yr, remark after remark have restricted the alternatives. No idea of modified gravity can clarify all observations. And physicists have positioned agency limits on the quantity of regular matter (vibrant, dim and every part in between) within the cosmos.That leaves dark matter to elucidate the speedy galaxies. This matter can be a brand new form of particle, with some unknown identification (or identities). It would not work together with gentle, in any other case we’d’ve seen it by now. It would not work together with the robust nuclear power — which binds collectively particles of matter — in any other case scientists would have detected its affect in atomic experiments. It may discuss to the weak nuclear power, however that power is so feeble and short-range that observing any deviations within the anticipated outcomes is difficult.Trillions of dark matter particles could also be streaming via you proper now, invisible and silent.However, dark matter betrays its presence via gravity, as a result of each single type of mass and power within the universe exerts some form of gravitational affect. So the one surefire option to examine dark matter is thru its gravitational interactions with regular matter, such because the motions of stars inside galaxies.But there could also be one other approach.The case of the surplus electronsIn a examine printed Jan. 28 to the preprint database arXiv, physicists proposed a brand new idea to elucidate what dark matter is and the way it behaves. But earlier than diving into their thought, now we have to introduce yet one more clue into this dark-matter hunt. The clue comes within the type of a wierd abundance of gamma rays noticed emanating from the middle of our Milky Way galaxy.Related: 11 fascinating information about our Milky Way galaxyGamma rays are the highest-energy type of radiation potential, and so they normally solely come into existence from some critically high-energy occasions, comparable to stars going supernova. But there are extra gamma rays than you’d count on within the galactic middle given how uncommon such cataclysmic occasions there are. So, it is potential, this idea proposed, that gamma rays could emerge as a byproduct of high-energy electrons.These high-energy electrons, that are a form of particle often called “leptons” and far simpler to provide than gamma rays instantly, emanate from some supply and journey all through the galactic middle. The electrons themselves are undetectable (they’re very, very tiny), however as they flood via interstellar house, they’ll sometimes slam into a random passing photon (a lightweight particle).That photon, most definitely one thing innocuous and low-energy, collides with the aggressive electron; the collision boosts the photon’s power a lot that it begins to present off gamma rays that we are able to see.Those collisions probably clarify the surplus gamma rays, however the place do these high-energy electrons come from?Jumping via the portalLet’s recap what we all know. One, dark matter interacts solely via gravity. Two, high-energy leptons floating across the galactic middle could clarify the additional gamma rays we see there. Three, as a result of in our personal galaxy the core has the best density of matter, we expect that there’s additionally a big focus of dark matter there.Coincidence? Or conspiracy?The hyperlink between these two observations has a suitably superior identify: leptophilic gravity portals, as detailed by Sun Xu-Dong and Dai Ben-Zhong, of the China Key Laboratory of Astroparticle Physics, of their arXiv paper. The examine has but to be peer-reviewed.Let’s begin with the “gravity portals” half. As far as we perceive gravity, it simply pulls on stuff. Earth pulls on the moon; the solar pulls on Earth; stars in a galaxy pull on one another, and so forth. And gravity does a extremely, actually good job of pulling.So on the face of it, the one factor gravity can do to dark matter is … pull. But our understanding of gravity is incomplete. Physics can clarify gravity operates on the massive scale, however there is not any so-called quantum idea of gravity, which might describe robust gravity working at very tiny scales. And on this regime, gravity may need some surprises in retailer.The different forces of nature are able to annihilating, reworking and creating particles on a regular basis. The weak nuclear power, for example, can change a proton into a neutron, triggering radioactive decay. A particle and its antiparticle can join through the electromagnetic power, annihilating one another in a burst of radiation.So possibly gravity, in excessive instances, can carry two dark matter particles collectively and destroy them, turning them into … something, actually.And in response to the theoretical mannequin outlined by the researchers, possibly these dark matter particles can rework into leptons. Hence the “leptophilic” a part of the identify, which implies “lepton-loving.” According to the brand new idea, dark matter particles can sometimes annihilate one another via nothing greater than probability gravitational interactions. These probability interactions are identified within the physics jargon as “gravity portals,” since they provide a approach for particles to work together via gravity alone. The product of that collision is a high-energy electron. These interactions can be way more widespread within the galactic middle, the place the density of dark matter is probably going highest. Those electrons would then journey on, finally placing a low-energy photon and turning into a gamma ray, inflicting the surplus that we observe.Yes, this concept is a stretch. But provided that physicists are within the dark relating to the identification of dark matter, new concepts are at all times welcome. And this idea was particularly designed to match the remark of the gamma rays. But as soon as that doorway has been opened, permitting dark matter particles to remodel into common matter (leptons, on this case), extra theoretical work could be finished to see if there are different methods to check the idea.Originally printed on Live Science.
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