Case for axion origin of dark matter gains traction:
The existence of dark matter has been confirmed by several independent observations, but its true identity remains a mystery. According to this study, axion velocity provides a key insight into the dark matter puzzle. Previous research efforts have successfully accounted for the abundance of dark matter in the universe; however certain factors, such as the underproduction of axions with stronger ordinary matter interactions, remained unexplored.
By assigning a nonzero initial velocity to the axion field, the team discovered a mechanism—termed kinetic misalignment—producing far more axions in the early universe than conventional mechanisms. The motion, generated by breaking of the axion shift symmetry, significantly modifies the conventional computation of the axion dark matter abundance. Additionally, these dynamics allow axion dark matter to react more strongly with ordinary matter, exceeding the prediction of the conventional misalignment mechanism.
"The extensive literature on the axion was built upon the assumption that the axion field is initially static in the early universe," stated Keisuke Harigaya of the Institute for Advanced Study. "Instead, we discovered that the axion field may be initially dynamic as a consequence of theories of quantum gravity with axions."
Journal Reference:
Raymond T. Co, Lawrence J. Hall, Keisuke Harigaya. Axion Kinetic Misalignment Mechanism [open], Physical Review Letters (DOI: 10.1103/PhysRevLett.124.251802)
(Score: 0, Redundant) by Anonymous Coward on Saturday June 27 2020, @11:30AM (1 child)
Now we're getting an origin story for stuff that doesn't exist? Why don't they force physicists to work on things with potential practical value, like antigravity beams or perpetual motion machines.
(Score: 1) by khallow on Saturday June 27 2020, @12:03PM
(Score: 1) by anubi on Saturday June 27 2020, @12:17PM (3 children)
How do we distinguish this from burned out stars?
They would still have mass, but no lumenosity, making them difficult to see.
"Prove all things; hold fast that which is good." [KJV: I Thessalonians 5:21]
(Score: 3, Interesting) by khallow on Saturday June 27 2020, @12:41PM
For me, the biggest problem with exotic particle dark matter is how do you get it moving slow enough that it can be captured and concentrated by a galaxy? For example, typical neutrinos have many orders of magnitude over the kinetic energy they need to escape from the galaxy and to our knowledge, they don't interact with anything. You couldn't get a cloud of neutrinos distorting galaxy gravitational fields, because they wouldn't stick around.
(Score: 4, Informative) by zocalo on Saturday June 27 2020, @12:47PM
Dark Matter, is generally thought of as a more diffuse distribution of mass - dust, gas, atomic particules - that we are currently unable to identify beause it's not emitting or reflecting enough light/energy for us to detect, but being distributed over a much larger area. We think of stars as large objects, but space is still almost entirely empty; if you distribute a stellar mass with the typical density of a stellar dust or gas cloud, it's going to occupy a volume that measures light years on a side. Same overall mass, but much less likely to have an appreciable impact of a stellar orbit, let alone one that we can detect.
UNIX? They're not even circumcised! Savages!
(Score: 0) by Anonymous Coward on Saturday June 27 2020, @06:44PM
maybe when one of those entities consciously couples with a black hole, whence that disturbance in the force is eventually detected by LIGO?
(wait, that was in the news this week... an entity was detected after merging with a black hole. it was speculated to be a black hole smaller than current idea of smallest black hole or a 'dark' neutron star)
(Score: 2) by hendrikboom on Saturday June 27 2020, @12:37PM (3 children)
I do not understand what this summary could be saying.
What do the terms "initial velocity" and its apparent opposite, "static", even mean in a relativistic universe?
-- hendrik
(Score: 2) by Rupert Pupnick on Saturday June 27 2020, @01:05PM
And what does it mean for a “field” to have “velocity”? Certainly (as in EM theory) you can have waves within a field with velocity, but the field itself?
(Score: 3, Informative) by maxwell demon on Saturday June 27 2020, @01:10PM (1 child)
From a (very) quick look into the actual article, it seems that “velocity” here refers to the rate of change of field strength. “Static” then means the field does not change with time.
Relativity may affect how fast you perceive a field changing, but not whether it changes at all (well, there is an intermixing between spatial and temporal change, but I guess the static scenario also involved a spatially constant field)
The Tao of math: The numbers you can count are not the real numbers.
(Score: 2) by hendrikboom on Sunday June 28 2020, @01:54AM
That make sense. Thank you.
(Score: 0, Redundant) by Gaaark on Saturday June 27 2020, @01:50PM (4 children)
"The existence of dark matter has been confirmed by several independent observations, but its true identity remains a mystery."
---phys.org
"If you tell a lie big enough and keep repeating it, people will eventually come to believe it."
---Goebbels
Where is this confirmation? Show me...please!
--- Please remind me if I haven't been civil to you: I'm channeling MDC. ---Gaaark 2.0 ---
(Score: 2, Informative) by Anonymous Coward on Saturday June 27 2020, @02:37PM (1 child)
Go do your own homework. Start with wikipedia's [wikipedia.org] citation list:
EXISTENCE AND NATURE OF DARK MATTER IN THE UNIVERSE [escholarship.org]
Planck Mission Brings Universe Into Sharp Focus [nasa.gov]
Dark Energy, Dark Matter [nasa.gov]
Collection of all Planck Mission publications [esa.int]
Planck captures portrait of the young Universe, revealing earliest light [cam.ac.uk]:
(Score: 2) by Gaaark on Sunday June 28 2020, @02:35PM
"We are much more certain what dark matter is not than we are what it is."
---https://science.nasa.gov/astrophysics/focus-areas/what-is-dark-energy/
Yup!
Absolute confirmation! You are soooooooooo right and I am soooooooooo wrong!
Dark matter is a kludge to save GR: nothing less, nothing more. I want REAL proof, not Myron the Magnificent.
--- Please remind me if I haven't been civil to you: I'm channeling MDC. ---Gaaark 2.0 ---
(Score: 1, Informative) by Anonymous Coward on Saturday June 27 2020, @02:54PM
https://en.wikipedia.org/wiki/Deferent_and_epicycle [wikipedia.org]
(Score: 0, Flamebait) by Anonymous Coward on Saturday June 27 2020, @10:28PM
What, other people should be responsible for your own ignorance now ?
Get out of your mother's fucking basement and go learn some basic astrophysics, loser.
(Score: 1, Informative) by Anonymous Coward on Saturday June 27 2020, @02:31PM
Space Time to the rescue covering answering all questions including dark matter tie-in
https://www.youtube.com/watch?v=e7yXqF32Yvw [youtube.com]
(Score: 3, Touché) by The Mighty Buzzard on Saturday June 27 2020, @03:18PM (4 children)
You're going to say (imaginary) dark matter must be made of (also imaginary) axions because you changed one of the properties (you imagine) axions have? I need a job like that.
My rights don't end where your fear begins.
(Score: 2) by inertnet on Saturday June 27 2020, @03:57PM
I started out with a very low initial velocity, but I still acquired excess matter while getting older.
Possible additions for your sig:
1st sentence: ", often enough"
2nd sentence: ", loud enough"
(Score: 0, Flamebait) by Anonymous Coward on Saturday June 27 2020, @10:30PM (2 children)
And what do you know. One more ignorant fucking basement dweller who thinks he's smarter that all astrophysisists.
The Internet really is the black hole that sucks all the losers of society.
(Score: 2, Informative) by The Mighty Buzzard on Saturday June 27 2020, @10:49PM
You don't need to be a physicist to see them claiming shit is true that they can't prove. That ain't science, that's religion.
My rights don't end where your fear begins.
(Score: 2) by Gaaark on Sunday June 28 2020, @02:46PM
All you have to do is show us the PROOF that all these physicists have.
Do that and you will have converts. But you can't, because there is NO proof: DM is a kludge physicists came up with SOLELY for the purpose of saving GR.
Instead of acknowledging GR has another problem and needs to be resolved some other way, they waved their hands and came up with an ever changing DM.
Waving hands is NOT proof: if you think we're just basement dwellers who are stupid, SHOW US THE PROOF, not hand waving, ever changing shit made up to fill a gap. But you and all your GR religion following physicists have no proof to show because there is none.
So, basement dwellers one, GR religion following physicists zero.
--- Please remind me if I haven't been civil to you: I'm channeling MDC. ---Gaaark 2.0 ---
(Score: 3, Insightful) by KritonK on Saturday June 27 2020, @07:36PM (1 child)
When making up Greek-sounding words, such as "axion" (by combining [etymonline.com] "axial" with the Greek suffix "-on"), make sure that you don't end up with an actual Greek word, in this case ἄξιον [wiktionary.org] = worthy, which will most likely mean something completely different.
Not that I could make heads or tails regarding what axions [wikipedia.org] are, or what is the problem [wikipedia.org] that their existence is supposed to solve.
(Score: 0) by Anonymous Coward on Sunday June 28 2020, @05:45AM
Because in American, every word means exactly one thing.