Dark Matter May Be Completely Invisible, Concludes World's Most Sensitive Search

Forbes ^ | 07/21/2016 | Ethan Siegel

[Phlap]

In an announcement earlier today, the LUX Collaboration — running the Large Underground Xenon experiment — performed the longest, deepest, most sensitive search for dark matter ever, using 370 kilograms of liquid xenon with the detector running for a total of 20 months. The final result? Not a single dark matter collision was observed.

[Zeneta]

So what type of dark matter particle was this particular experiment trying to detect?

They are trying to detect something that is completely unknown and has eluded all previous efforts to find.

If you were to find it?

You could name it "Moonman62"

[Zeneta]

Interesting.

I have a feeling that both “Dark Matter and Dark Energy” are a lot darker than most people realize.

[zeugma]

The probabilities against such a thing would be astronomical.

I saw what you did there.

[beethovenfan]

DARK MATTER LIVES !!

[zeugma]

Open Universe?

Forever expanding, meaning time without end?

I refuse to believe this. What it essentially means is that the universe expands forever, and eventually everything in the universe will reach a temperature of absolute zero. Any life in the universe would be long dead before that point is reached. Regardless of what "they" say, they'll never be able to convince me of it. I don't even care if that belief is irrational. Ultimately, we won't know for sure for a loooooooooong time, so it really doesn't matter.

[tet68]

#darkmatterlives ?

We can’t see it, we can’t measure it, but it’s got to
be there! Cause if it isn’t then all our thinking is
wrong? Hmmmmmm.

[Hulka]

Thanks.

Post 45. . .in this article is speaks to many aspects of an open universe; life, intelligent life, and how it may exist in a cold universe.

Lots of math (’math is hard’), too much for this political science/criminal justice major to handle. Perhaps you might find interesting.

[Moonman62]

The answer is they were looking for Weakly Interacting Massive Particles or WIMPs. It will take more sensitive detectors and about 10 to 15 more years to completely eliminate all WIMP models for dark matter.

Zineta seems particularly brilliant. A question for you is what other types of particles are theorized to make up dark matter besides WIMPs?

[Boogieman]

“A question for you is what other types of particles are theorized to make up dark matter besides WIMPs?”

Well, they theorize stuff like axions and sterile neutrinos, but I don’t really bother following those theories much since I don’t believe there is much of a probability any of them are correct. Once they’ve ruled them all out, they’ll probably just propose more imaginary particles to chase after for a few more decades.

[Zeneta]

Thanks, I think, but not Brilliant.

I just like to ask questions.

Correct me if I’m wrong, but we seem to be aware of what has been described as a “Particle Zoo”.

The LHC has said they found the Higgs Boson or God Particle.

Kinda like a “controlling particle” for the rest of the zoo.

That said, I get the impression that the search for Dark whatever is somehow outside of what we have discovered in our physical world.

Since you are begging the question, I’d like a hint.

[Reily]

Well is some ways it's an exciting time for theoretical physics!
A physical theory is pushed and used to “explain things” until it breaks. Like where quantum theory began, with the “Ultraviolet Catastrophe”. So time to re-sharpen those pencils (get more lead if mechanical), get more chalk, more pads of paper & get at it! — Physics Boys & Girls !
The HUGE problem with modern particle physics is the problem of “experimentation’ needing galactic levels of energy to directly test a theory (or part of a theory!) is a non-starter.

[Zeneta]

At this point I tend to take a Metaphysical view of what is known and can be known.

The more we discover the more we uncover the things we don’t know.

And we keep pressing on because that is our nature. It’s in our nature to continually ask those questions and seek out the answers.

I have often considered if we will ever reach an end to understanding. Can we reach its end? Can we ever really know everything?

What would happen to our society if or when we do?

I can’t help but imagine that if we were ever to reach that point, literally everything would come crashing down. It would be the beginning of the end for all of mankind.

Sounds nuts I know.

[goldbux]

* * *

[ZOOKER]

Years ago I heard a particularly unsatisfying theory on celestial mechanics. Call it the "tension of space" theory.

Seems that the empty space between stars somehow creates "tension" that results in the spontaneous creation of matter.

Now, why something that's empty, devoid of anything, should have tension, is beyond me. And how matter is created from nothing (except the aforementioned tension), is equally baffling.

That must be the answer, though, and the reason scientists can't find it. There's too much matter in their lab! Dark matter only exists when there's nothing else there! And you'll never be able to observe it, because as soon as you get close to it, space is no longer empty there. Tension and dark matter disappear!

Anyone who's ever tried to find the pot of gold at the end of the rainbow will understand the logic...

[Moonman62]

At this point I tend to take a Metaphysical view of what is known and can be known.

The more we discover the more we uncover the things we don’t know.

I can only think of the words of Donald Rumsfeld:

Reports that say that something hasn't happened are always interesting to me, because as we know, there are known knowns; there are things we know we know. We also know there are known unknowns; that is to say we know there are some things we do not know. But there are also unknown unknowns – the ones we don't know we don't know. And if one looks throughout the history of our country and other free countries, it is the latter category that tend to be the difficult ones.

And we keep pressing on because that is our nature. It’s in our nature to continually ask those questions and seek out the answers.

Perhaps that is our purpose.

I have often considered if we will ever reach an end to understanding. Can we reach its end? Can we ever really know everything?

What would happen to our society if or when we do?

I can’t help but imagine that if we were ever to reach that point, literally everything would come crashing down. It would be the beginning of the end for all of mankind.

What happened to humans in Clarke's Childhood's End or Asimov's The Last Question? Our fate and purpose have been pondered by people before us. Clarke said perhaps our purpose is not to worship God but to create him. If a person believes Jesus is divine, then Mary was a co-creator, so the idea is not all that outlandish.

[Zeneta]

I would agree that it is our purpose (to seek the truth).

Something uniquely Human to be sure.

But even as Clarke and Asimov may have suggested, the Creation of the supernatural in ones mind doesn’t put an end to the continuation of our purpose.

Science and Christianity are on parallel tracks that are both seeking a truth.

A definitive.

Can you imagine a world in which the scientists tell us that everything that can be known is known?

What do you think that would do to our purpose?

[Colinsky]

Sometimes in science it takes the older generation dying off before they can break out of the herd mentality and embrace new theories.

Or, as Max Planck said, "Science advances one funeral at a time."

[Colinsky]

The rotational rate of galaxies is independent of distance from the core. Pluto takes 248 years to circle the sun, Mercury 88 days. With stars, it’s as if Mercury and Pluto circled the sun at the same rate.

[Lonesome in Massachussets]

The high school math explanation is that centripetal force is equal to w^2 x R, w (omega) = radial velocity = 2 x pi / T_orbit, R = distance from central attracting body. Gravitational force goes as 1/R^2. Hence, for a body in circular obit,

w^2 x R = mu/R^2 ,

mu is a characteristic of the central body, its gravitational constant and is proportional to its mass.

More high school math, solve for w:

w = (mu)^(1/2) x (R)^(-3/2)

The gravitational attraction of a spherical shell is zero for points inside of it, and acts as if all its mass were concentrated at its center for points outside. If galaxies are embedded in a spherical soup of particles resembling neutrinos, but more massive, and not interacting with “ordinary” matter at all, except gravitationally, the gravitational attraction as a function of distance from the center of the sphere (assuming uniform density) would go as:

F(R) = G x rho x 4/3 x pi x R^3 /R^2

G = Newtonian gravitational constant

rho x 4/3 x pi x R^3 = mass within sphere of radius R

rho = density, mass per unit volume

pi = 22/7

Canceling terms:

F(R) = (G x rho x 4/3 x pi) x R

and

w^2 x R = F(R) = (G x rho x 4/3 x pi) x R

solving for w

w = (G x rho x 4/3 x pi)^(1/2)

which is independent of R, if rho is independent of R

the stuff making up rho does not show in telescopes, hypothetically because it does not interact with photons (is electrically neutral). If it does not interact with the weak or strong subatomic forces, there is no way of ever detecting them.

Stay tuned for further developments.

[PIF]

The ‘93 calculation which gave rise to the whole dark matter therory are hugely out of date as much more of the Universe has been “found” since then.