Dark matter/Dark Energy

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Sirius B Project Donor
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Message 1948037 - Posted: 5 Aug 2018, 16:45:15 UTC

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Message 1948041 - Posted: 5 Aug 2018, 17:06:43 UTC - in response to Message 1947784.  

Energy cannot be created or destroyed in a closed system.

String theory implies this may not be a closed system.
Then you have to accept the idea of multiverses that somehow are connected to our universe.
But our universe has a finite mass/energy and the law of conservation of energy rules here.

A clear demonstration is over in the politics boards. There are posters over there whose view points can only come from living in an alternate reality.
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Message 1948043 - Posted: 5 Aug 2018, 17:23:33 UTC - in response to Message 1948041.  

Energy cannot be created or destroyed in a closed system.

String theory implies this may not be a closed system.
Then you have to accept the idea of multiverses that somehow are connected to our universe.
But our universe has a finite mass/energy and the law of conservation of energy rules here.

A clear demonstration is over in the politics boards. There are posters over there whose view points can only come from living in an alternate reality.
LOL:) And some political world leaders as well.
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Message 1948177 - Posted: 6 Aug 2018, 16:35:03 UTC - in response to Message 1947440.  

Sic transit gloria !. My alter ego would have had all of this sorted out if it were not for the good wifey.

post a picture
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Message 1962112 - Posted: 27 Oct 2018, 12:04:37 UTC - in response to Message 1948177.  

Over a hundred years since it was first theorized , physicists have yet to discover solid evidence for a dark matter particle, despite the many experiments searching for it. Most physicists are sure that it’s there, but its elusive nature has becoming increasingly frustrated the harder they try.


What's keeping us from discovering dark matter?

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Message 1962268 - Posted: 28 Oct 2018, 11:57:18 UTC

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Message 1962269 - Posted: 28 Oct 2018, 12:16:10 UTC

The status of Dark Matter in the Universe.
https://ned.ipac.caltech.edu/level5/Sept17/Freese/frames.html
Abstract: Over the past few decades, a consensus picture has emerged in which roughly a quarter of the universe consists of dark matter. I begin with a review of the observational evidence for the existence of dark matter: rotation curves of galaxies, gravitational lensing measurements, hot gas in clusters, galaxy formation, primordial nucleosynthesis and cosmic microwave background observations. Then I discuss a number of anomalous signals in a variety of data sets that may point to discovery, though all of them are controversial. The annual modulation in the DAMA detector and/or the gamma-ray excess seen in the Fermi Gamma Ray Space Telescope from the Galactic Center could be due to WIMPs; a 3.5 keV X-ray line from multiple sources could be due to sterile neutrinos; or the 511 keV line in INTEGRAL data could be due to MeV dark matter. All of these would require further confirmation in other experiments or data sets to be proven correct. In addition, a new line of research on dark stars is presented, which suggests that the first stars to exist in the universe were powered by dark matter heating rather than by fusion: the observational possibility of discovering dark matter in this way is discussed.
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Message 1962295 - Posted: 28 Oct 2018, 16:55:04 UTC - in response to Message 1962278.  
Last modified: 28 Oct 2018, 17:07:14 UTC

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Message 1962339 - Posted: 29 Oct 2018, 0:05:15 UTC

If dark matter/energy doesn't exist then a lot of scientists are going to have to go back to the drawing board and their equations to come up with a better explanation of what all the observations really mean.
Bob DeWoody

My motto: Never do today what you can put off until tomorrow as it may not be required. This no longer applies in light of current events.
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Message 1962416 - Posted: 29 Oct 2018, 14:51:43 UTC - in response to Message 1962339.  

If dark matter/energy doesn't exist then a lot of scientists are going to have to go back to the drawing board and their equations to come up with a better explanation of what all the observations really mean.


+1 My thoughts exactly
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Message 1962420 - Posted: 29 Oct 2018, 15:17:43 UTC

Astronomers find evidence of dark matter and dark energy. Physicists search for dark matter particles and find none. It looks like the story of blind men describing an elephant. Maybe a basic question lies behind all this. What is reality? This is a problem of quantum theory that is hotly debated.
Tullio
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Message 1962479 - Posted: 29 Oct 2018, 22:49:18 UTC - in response to Message 1962420.  

LHC are trying to find the invisible dark matter particles indirectly by checking if mass is "missing" after collision.
https://atlas.cern/updates/physics-briefing/chasing-invisible
Although the existence of Dark Matter is well-established, its nature and properties still remain one of the greatest unsolved puzzles of fundamental physics. Excellent candidates for Dark Matter particles are weakly interacting massive particles (WIMPs). These “invisible” particles cannot be detected directly by collision experiments.
At the LHC, most collisions of protons produce sprays of energetic particles that bundle together into so-called “jets”. Momentum conservation requires that if particles are reconstructed in one part of the detector there have to be recoiling particles in the opposite direction. However, if WIMPs are produced they will leave no trace in the detector, causing a momentum imbalance called “missing transverse momentum” (ETmiss). However, a pair of WIMPs can be produced together with a quark or gluon that is radiated from an incoming parton (a generic constituent of the proton) producing a jet which allows us to tag this kind of events.
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Message 1962489 - Posted: 30 Oct 2018, 0:52:28 UTC - in response to Message 1962420.  

Astronomers find evidence of dark matter and dark energy. Physicists search for dark matter particles and find none. It looks like the story of blind men describing an elephant. Maybe a basic question lies behind all this. What is reality? This is a problem of quantum theory that is hotly debated.
Tullio

Physicists search with the electromagnetic spectrum for a particle Astronomers say only has a gravitational spectrum. Am I the only one seeing this might be a problem?
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Message 1962527 - Posted: 30 Oct 2018, 5:20:12 UTC - in response to Message 1962489.  

Astronomers find evidence of dark matter and dark energy. Physicists search for dark matter particles and find none. It looks like the story of blind men describing an elephant. Maybe a basic question lies behind all this. What is reality? This is a problem of quantum theory that is hotly debated.
Tullio

Physicists search with the electromagnetic spectrum for a particle Astronomers say only has a gravitational spectrum. Am I the only one seeing this might be a problem?

Yes I have pondered that too. Maybe what they have detected isn't what they think it is.
Bob DeWoody

My motto: Never do today what you can put off until tomorrow as it may not be required. This no longer applies in light of current events.
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Message 1962539 - Posted: 30 Oct 2018, 7:09:15 UTC

Physicists seek particles, that is fermions, with half integer spin. What if dark matter is a Bose-Einstein condensate? Recently a BE condensate has been created in orbit on the ISS.
Tullio
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Message 1968892 - Posted: 5 Dec 2018, 23:27:05 UTC - in response to Message 1962539.  

Can't rule it in yet. Still not ruling dark matter out.


Underground experiment casts doubt on controversial dark matter claim


Twenty years ago, physicists with the Dark Matter (DAMA) experiment in Italy’s subterranean Gran Sasso National Laboratory announced they had detected particles of dark matter—the mysterious stuff whose gravity presumably holds the galaxy together. Now, the first experiment designed to directly test DAMA’s controversial claim has released its first data. Physicists working with the COSINE-100 detector in South Korea say they see no sign of dark matter—but still need a couple more years to really put the screws to the DAMA claim.



COSINE-100 experiment investigates dark matter mystery


December 5, 2018, Institute for Basic Science
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Message 1970035 - Posted: 12 Dec 2018, 22:52:50 UTC - in response to Message 1968892.  

In findings published today in The Astrophysical Journal, University of Texas at Austin astronomers report that they have stumbled on an extraordinary galaxy that may corroborate a recently contested theory about dark matter.

Dark matter is matter that does not give off any light, but is detectable by its gravitational pull on other matter. It was first discovered in the 1970s in studies of spiral galaxies, whose outer regions rotated too fast only to be driven by the visible stars and gas in those regions. Astronomers reasoned there must be more mass that is unseen. Decades of galaxy observations have shown that almost all galaxies contain huge quantities of this "dark matter," and that, in fact, there is about five times as much dark matter as there is normal, visible matter in the universe.

Interesting!

https://phys.org/news/2018-12-astronomers-dark-dominates-cosmic.html
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Message 1972210 - Posted: 27 Dec 2018, 23:56:04 UTC - in response to Message 1970035.  

NASA Hubble Telescope provides new way to 'see' dark matter

Dark matter was so named because it doesn't interact with anything we can readily detect or see. It's basically invisible to us.

The only reason we believe dark matter makes up 85 percent of the known universe is because of its observable gravitational effects. Now, a new method devised by astronomers in Australia and Spain, using images captured by NASA/ESA's Hubble Space Telescope, may allow us to "see" dark matter using very faint light found in galaxy clusters.

hmmm?

Hi Julie.
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Message 1972307 - Posted: 28 Dec 2018, 12:16:08 UTC

Fritz Zwicki wrote of "missing mass" in 1936 about the rotation of spiral galaxies but nobody followed him. Early prophets are considered fools.
Tullio
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Message 1972313 - Posted: 28 Dec 2018, 14:30:14 UTC - in response to Message 1831151.  

As I have often mused: The universe itself may be rotating.
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Message boards : Science (non-SETI) : Dark matter/Dark Energy


 
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