Dark Matter Explained

 

the identity of dark matter is  undoubtedly one of the most elusive  space mysteries of our generation  it's an exciting time with many possible  candidates  put forward by the scientific community  and even more ways to have the chance to  detect them  it's time to take a fresh look at what  dark matter  is or isn't the idea  new developments in dark matter theory  and its connection to other visible  structures is enabling physicists  and astronomers to design experiments  that edge ever closer to their dark  region of space  as a result there are a bunch of dark  matter candidates that interact with  ordinary matter  on a gravitational level we now know  that the total mass  energy of the universe compromises of 68  dark energy 27 dark matter with ordinary  matter and electromagnetic radiation  taking up a paltry 5 spiritualists and  religion  have always maintained that there is a  vast well beyond the limits of our sense  and  scope of comprehension and it looks like  they might have been on the right track  after all  galaxies would literally fly apart word  not for the mass  of unseen matter let alone have the mass  to initiate the gravitational torsion  required to consolidate and form the  history  it was only relatively recently that we  accepted 85  percent of the matter in the universe  was dark matter  mostly because of observed gravitational  effects that can't be explained  by the theory of gravity based on the  amount of normal matter  british physicist william thompson  otherwise known as lord kelvin  not only had a unit of temperature as  his namesake but was also the first to  put forward the notion of  unseen bodies in an 1884 lecture  he estimated that the mass of the galaxy  was different to the mass of the stars  and theorized that many stars might be  invisible  the concept was built upon in 1922  by dutch astronomer kakabus captain who  observed that stellar velocities in the  local galactic neighborhood  were only possible if the mass in that  galactic plane was greater  than what could be observed the term  dark matter was actually coined from the  german  dunkel materi by swiss physicist fritz  zwicky in 1933 after discovering that  the motions and brightness of certain  galaxies  contained up to 400 times more mass than  what was visible  vera rubin and kent ford worked during  the 60s and 70s  to develop a new spectrograph to measure  the velocity curve of spiral galaxies  with greater  accuracy the result it showed that most  contain at least six times as much dark  as visible mass the now  we've known it's been there for a long  time and we've sifted through the  evidence like a detective trying to  solve a crime  just like any murder mystery the next  point of call  is identifying likely suspects before  asserting them  one by one until we find the culprit  dark matter has  mass but does not absorb reflect or emit  electromagnetic radiation it does  interact with regular matter by gravity  so this must be the key to solving the  case  it's all hypothetical the most probable  explanation is that dark matter  consisted of  hypothetical particles whose existence  is based on no real evidence  in a nutshell it's like giving a sketch  artist an extremely vague description of  the perp  the sources of are actually divided into  types cold  dark matter cvm and hot dark matter  hdm the reference has nothing to do with  temperature  but speed a cold particle moves slower  than the speed of light  a hot particle traveling at ultra  relativistic velocities exceeding it  neutrinos were once thought to travel at  faster than light speeds  however the anomaly results were  debunked  they stay just under the universe's  speed limit  don't be a whim no it's not an insult a  wimp is a weekly  interacting massive particle and a  strong cdn candidate that may be wearing  the dark matter mask  it's proposed that they interact for  themselves by using just two of the four  fundamental forces  weak nuclear force and gravity apart  from marginally interacting with  themselves  these wimps basically ignore other  matter and the electromagnetic spectrum  the profile of a supersymmetric partner  particle would be a natural candidate  for dark matter  and a wimp would be the lightest one  when a wimp contacts another wimp  they wouldn't bounce off each other they  would destroy one another in a violent  annihilation reaction  the result is a high energy gamma wave  emission  the only evidence that such a reaction  took place  this would explain why there is a source  of unknown gamma radiation coming from  the center of the milky way  additionally when physicists run  simulations of the early universe  wimp lookalikes are formed and managed  to stay intact until the modern day  the numbers of whims formed even match  the predicted abundances of dark matter  based on the current calculations the  big hole in the theoretical particles  alibi  is that we have already had success  detecting neutrinos  which are also chargeless ghost-like  particles that have nearly no mass  and fit the weakly interacting profile  of a win  chubby neutrinos so is dark matter made  up of neutrinos  then the answer is probably not their  extremely low mass and close to light  speed travel  doesn't fit into an astrophysical model  of what  cdm is however it hasn't ruled them out  as hdm candidates though  there may be a much larger cousin dubbed  the sterile neutrino  that were yet to discover such a  particle would weakly interact with the  baryonic matter and ignore the  electromagnetic spectrum  while having enough mass to account for  the gravitational influence of dark  matter  despite having a larger mass than  regular neutrinos  the sterile variety would be tricky to  arrest for questioning  most neutrinos are made by stars and  mass and although  a sterile neutrino may be a dead ring of  hcm  the method of possible production  remains a mystery  the lightweights axions are very similar  to photons of energy  though instead of being massless they  contain a tiny  tiny amount of mass something akin to  one billionth the weight of an electron  super small has to be almost  undetectable  they're an interesting candidate whose  existence could kill  two birds with one stone and solve a  couple of astrophysical mysteries  despite the universe initially having  matter and antimatter symmetry  mata is favored in a phenomenon called  the charge  parity violation problem axions  conveniently solve this imbalance by  being packed extremely tightly into the  universe  such a high density of ultralight would  also explain the mass of dark matter  macho man not all dark matter candidates  are theoretical though and here's where  it gets  weird machos are massive astrophysical  combat halo objects  or the remnants of dead stars like white  dwarfs and neutron stars and failed  stars like brow dwarfs  they are real particles still composed  of baryonic matter  though the properties may be pretty  exotic by our standards  they would still interact with  fundamental forces in conventional  and predictable ways but are still  undetectable  in the sense that they do not emit  electromagnetic radiation  dark matter is unlikely to be made up of  machos and the mass  just isn't there it's insufficient to  account for the gravitational effects  if dark matter was made of machos there  would be  much more prevalent in the universe  an illusion modified newtonian dynamics  or monde  may explain the gravitational phenomenon  thought to be created  by dark matter as a cosmic illusion  caused by a misunderstanding of the  nature of gravity  or some other kind of yet to be  discovered gravitational wave  dark matter doesn't have to be matter at  all  if it sounds too good to be true it  usually  is one theory can explain some but not  all  of the observed effects of dark matter  on the visible universe  sucked in there could be another dark  horse in the pursuit of the dark matter  villain  the andromeda galaxy is notoriously  heavy with dark matter  and a good choice to test out this next  theory primordial black holes were made  just  after the birth of the universe and are  just one tenth of a millimeter in  diameter  they were created due to ripples small  patches of over density in the newly  formed space-time continuum  they fit the criteria of dark matter we  can't observe them  they have dense mass they don't interact  with electromagnetic spectrum  so much as swallow it they have the  gravitational force  required to pull galaxies together  scientists  assessed the andromeda galaxy and found  evidence of these primordial  black holes but sadly they account for  just point  one percent of all dark matter mass  within  there are two possible explanations  either  we are very poor at detecting them or  there is another particle  waiting in the waves there is no doubt  that at least some dark matter is made  up of these pint-sized black holes  but the question still remains as to  what  exactly constitutes dark matter