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stargazer represent the motions of hundreds of stars in theMilky Wayin order to infer the amount of dark matter that must be tugging on them from the locality of our sun . Their surprising stopping point ? There ’s no dark matter around here .
As the researchers indite in a forthcoming paper in the Astrophysical Journal , the star movement implies that the stars , all within 13,000 light - years of Earth , are gravitationally attracted by thevisiblematerial in oursolar system — the Dominicus , planet and surrounding flatulence and dust — and not by any unobserved thing .
This artist’s impression shows the Milky Way galaxy. The blue halo of material surrounding the galaxy indicates the expected distribution of the mysterious dark matter, which was first introduced by astronomers to explain the rotation properties of the galaxy and is now also an essential ingredient in current theories of the formation and evolution of galaxies.
" Our calculation show that [ dark matter ] should have shown up very clearly in our measurements . But it was just not there ! " said lead study source Christian Moni - Bidin , an astronomer at the University of Concepción in Chile .
If the psychoanalysis of the data from Chile ’s European Southern Observatory ( ESO ) is right — a full-grown " if , " several physicists say — it overturns the 10 - old hypothesis that dark matter permeates space in our region of the Milky Way . Dark matteris an unseeable material thought to make up 80 percentage of all issue in the universe . Although it does n’t interact with twinkle and so can not be consider , its comportment is invoked to excuse why the outskirts of galaxies , including the Milky Way , go around much more cursorily than would be expected based on the gravitative puff of visible matter alone . Commonly accepted as fact , dark subject plays an essential use in model of wandflower organisation and development , and several experiments are under way todetect dark affair particles on Earth .
But if moody matter is n’t here in the solar system , it may not be anywhere , because its statistical distribution through the Galax urceolata would have to be super funny to forfend this realm in space . " Modern theory have serious troubles to explain the geological formation of a [ dark matter ] gloriole so peculiarly shaped , " Moni - Bidin toldLife ’s Little Mysteries .
Scott Tremaine , professor of physics at Princeton University ’s Institute for Advanced Study , said , " If the authors ' conclusions are right , this is indeed a serious blow to dark matter . "
next astronomical surveys , such as theEuropean Space Agency ’s Gaia mission , will clarify the situation by follow the movements of million of stars , instead of just C . But in the meantime , by call dark topic into question , the new ESO determination invites give-and-take of a topic that has n’t gotten much airtime in recent year : What other theories could account for the gyration of galaxies , as well as other observations explained by drear matter ? If not dreary matter — or , at least , not the sullen matter we expect — then what ? expert have a few other options , though they ’re not nearly as satisfying .
Gravity 2.0
If the force of somberness is a circumstances messy than Newton and Einstein think , then it could account for the speedy rotation of volute Galax urceolata without requiring black matter . Forgravity to cannonball along up starson a coltsfoot ’s edge , it must diverge from the " opposite - square law " — the linguistic rule that gravitational attraction decreases by the lame of the distance out from something — at galactic distance . In other words , the force would ask to suddenly fortify at the boundary of galaxies . But for it to act that room , gravity fields and the equations associated with them would have to be tremendously convoluted . [ Top 3 Questions People demand an Astrophysicist ( and Answers ) ]
The possibility is called " modified Newtonian dynamics , " or MOND . " The nicest of the alternate manikin for spiral galaxies is the alternative sobriety theory MOND , as it seems to be capable to [ mathematically ] regurgitate the galaxy revolution curves with few assumption built into it , " said Douglas Clowe , an astrophysicist at Ohio University who study dark matter .
However , MOND does n’t fill as many gaps as dark topic does : it works utterly only for spiral Galax urceolata , Clowe say . For elliptical galaxies , galax mathematical group , coltsfoot clusters , and larger - scale bodily structure , the possibility does n’t quite fit observations , and so it requires that supernumerary thing — i.e. , saturnine matter — be arouse once again . " So alternatively of just using an unexplored particle to explain our notice of structure in the universe , MOND necessitate both an undiscovered molecule and a modification to the gravitative - force law , " he tell .
Another bash against MOND is that it , like the dark topic possibility , does n’t cope with the novel ESO findings . According to Moni - Bidin , because the team member used Newtonian gravity in their calculations , MOND would foretell a discrepancy to arise in the amount of mass they measure in the solar scheme . " MOND expect a ' phantom disk ' of unseen matter to be detected in a work like ours , " he say — just as using Newton ’s law of nature to pose the galaxy lead one to predict colored affair .
Fields of phions
John Moffat , a physicist at the Perimeter Institute for Advanced Study in Canada , has proposed a sub - theory of MOND called MOG , or " modify gravity . " He exact MOG explains the rum motion of wandflower , as well as galaxy bunch and bunch hit , without invoking sullen affair at any shell .
" I take Einstein ’s gravity and I add to this three flying field , " Moffat explained . One of the field has a mass , and this enter variations in the force police force at different distance scales . However , so as to have a mass , the field of study must have a particle associated with it , which Moffat calls the phion . And , like sullen affair particles , the phion ’s existence has not been verified . [ Smart Answers for Crazy Hypothetical Questions ]
Warm and dingy
If the ESO psychoanalysis is correct , it could just imply that dark issue behaves very differently — or is distribute very differently in distance — than has been thought . " It would entail that dingy matter would need to be pass around on a wider scale within the internal theatrical role of a galaxy , " Clowe tell , " which is [ mathematically confirmed ] if you make the dark matter particle less monumental than the presently favored manakin . "
fit in to Douglas Spolyar , a dark matter theorist at the University of Chicago , the less monolithic smorgasbord is called tender dark subject . " People use it to explain two thing — one that you would have a kernel in your dark thing visibility , so dark issue stays unceasing inside some spoke in the galaxy . second , if you look at the sullen matter hoagy - haloes in the Milky Way , the total [ of warm dark matter ] are much lower , " he aver . That could explicate why the ESO astronomer did n’t see any dark matter in our cosmic neck of the woods . [ What If Our Solar System had Formed Closer to the Milky Way ’s Edge ? ]
However , the researchers tell thatcolddark matter speck are strongly preferred by cosmologists , because less massive dark particles would have problems work galaxies quickly enough to match astronomers ' observations of the early existence .
New theory
If future surveys of the motion of maven bolster the ESO finding , strongly suggest there really is no sullen matter in our area of the galaxy , then cosmologist may have to scrap all the current hypothesis and commence anew . " To date , a comprehensive relativistic theory alternative to the glum matter substitution class , able to explain the observations on all scales , from galactic gyration to the clump of galaxies , is not known , " Moni - Bidin order .
Princeton ’s Tremaine concurred : " I do n’t think any of the alternatives to dark matter are very potential . "
