
More bad news for controversial 20-year-old claim of dark matter detection - furcyd
https://arstechnica.com/science/2019/02/more-bad-news-for-controversial-20-year-old-claim-of-dark-matter-detection/
======
julius_set
This does beg the question that what if we as a collective also encounter
these sort of defects.

For example on a macro scale based on our vantage point from our planet we
only have a visible and limited line of sight to specific areas of the galaxy
and the visible universe. The same could be same for the atomicverse.

What if we are incorrectly making assumptions about things because we don’t
see the full picture of how things actually are conceived, embarrassingly so.
On the magnitude of way far off.

~~~
saagarjha
> What if we are incorrectly making assumptions about things because we don’t
> see the full picture of how things actually are conceived, embarrassingly
> so.

This could be true, but I wouldn't call it "embarrassing" to come to flawed
conclusions based on inabilities to gather evidence. That's how science works:
we do the best with what we have, and continuously try to gather more evidence
and refine our theories in response.

~~~
julius_set
There are many instances in history of “embarrassingly,”:

• The theory that the earth is not the center of the universe - people
persecuted sometimes killed for different assumptions. • Spontaneous
generation, the idea that life just arises out of nothing, at the time period
this was accepted and other ideas disregarded which led to many lives lost due
to disease. • Mental illness assumptions in the past led people to view people
with mental illness as possessed by demons, etc. leading to cruel and unusual
confinement for these individuals • Lots of other examples

I would also propose that when observing our primate ape cousins even the
smartest monkey to us appears to be “embarrassingly” putting together a
coherent picture of actual reality.

Then that proposes an interesting thought experiment. If we encountered an
alien species with as much intellectual distance from us as we are to the
monkeys, then how would our most innovative theories fare against theirs? I
would imagine we would be seen as “embarrassingly,” able to put even a
fraction of the puzzle together.

We have our senses, and therefore we design our materials and probes to match
our senses. Sometimes we can imagine high dimensionality in say the form of a
tensor? Sure. Maybe we don’t have a complete picture so we build and optimize
tools only related to our own sense processing. What if there are more than
our senses, and we are incapable of seeing a deeper image of reality? What if
have the senses of a snail as a comparison to an even more advanced species.

~~~
lisper
> If we encountered an alien species with as much intellectual distance from
> us as we are to the monkeys, then how would our most innovative theories
> fare against theirs?

That depends on how far you are willing to suspend disbelief in your concept
of what such an alien might look like.

Are they made of atoms? If so, then they are overwhelmingly like to have
senses very similar to ours. This is because our senses are fundamentally
rooted in the physics of atoms, and there just aren't that many fundamentally
different things that atoms can do. They can absorb and emit photons, they can
stick together and be pried apart, they can emit alpha and beta particles, and
they can fuse and fission. That's about it. And with those fundamental
building blocks there is only so much you can do. You can imagine, say, aliens
that can natively detect different parts of the E-M spectrum than we do, but
that's not going to lead them to new physics that we haven't discovered.

On the other hand, if these aliens are made of dark matter then all bets are
off. But given how hard it is for us to detect dark matter _at all_ it's hard
to imagine how we would get to the point where we would even recognize a life
form made of it, let alone figure out how to communicate with it.

~~~
thaumasiotes
> our senses are fundamentally rooted in the physics of atoms, and there just
> aren't that many fundamentally different things that atoms can do. They can
> absorb and emit photons, they can stick together and be pried apart, they
> can emit alpha and beta particles, and they can fuse and fission. That's
> about it. And with those fundamental building blocks there is only so much
> you can do.

Our traditional physical senses:

\- Sight. Based on interacting with photons.

\- Sound. This is based on atoms physically colliding with each other.
However, we process it using a complex apparatus that essentially performs a
Fourier transform on the raw air-pressure data, extracting the frequencies of
the wave pattern that reaches our ears on the assumption that a wave pattern
is what we will get.

\- Touch. This is based on atoms colliding with each other. It is set up more
for the detection of large-scale structural characteristics. (e.g. hard / soft
/ liquid)

\- Smell. This is based on atoms colliding with each other. It is totally
unlike touch in that the sense of smell processes molecules based on their
molecular shape -- the specific way in which they interact with dedicated
sensors -- rather than on their physical characteristics. At this level,
you're interacting with a molecule more than with a substance.

\- Taste. From a physics perspective, this is basically just the same thing as
smell. From a biology perspective, it's pretty different.

I don't see this as good evidence that the set of possible senses is
meaningfully limited by a simplistic view of how atoms can physically interact
with other atoms.

We have many other senses that are less obviously based in simple physical
interactions, like the sense of time.

Some people have had magnets implanted, leveraging their existing sense of
touch into a sense of magnetic fields. This is something humans don't
ordinarily have, and is actually not allowed for by your list of the
capabilities of atoms -- you forgot that atoms can hold an electric charge --
but is analogous to some other animals' ability to sense electric fields.

I'm curious how you think "emitting an alpha particle" differs from "being
pried apart" or "fissioning".

~~~
lisper
> many other senses

Yeah? Like what? You've listed two. Two is not "many".

You don't need to have a magnet implanted to feel a magnetic field. All you
have to do is hold two magnets close to each other.

As for our "sense" of time, this arises from the fact that our brains perform
data processing at a characteristic speed, and that in turn is an emergent
property of atoms.

> I'm curious how you think "emitting an alpha particle" differs from "being
> pried apart" or "fissioning".

Alpha-decay is spontaneous, fissioning generally needs to initiated by neutron
bombardment. "Being pried apart" was intended to refer to chemical reactions,
not nuclear ones.

~~~
thaumasiotes
> Yeah? Like what?

Most people try to support an argument with something stronger than "I don't
know very much".

You can sense acceleration.

You can sense temperature.

You can sense the position of the various parts of your own body.
("proprioception")

You can sense whether you need to eat, and what you should eat. ("hunger")

Note that from a physical perspective, hunger appears identical to taste and
smell. That is to say, it is implemented by special receptors that bind to a
particular molecular shape. But unlike those two, it is not general-purpose --
it is a computational artifact, the specialized means by which your digestive
system sends messages to your nervous system. But it is no less of a sense
than your others. A sense is a means of receiving input. This should tell you
that the number of senses you may experience is not limited by the number of
interactions one atom may have with another atom; it is at least as large as
the number of different types of computation you might want to do.

If you're really interested in a catalog of senses, I suggest checking out the
psychology literature. And whether you're interested or not, I suggest trying
to base your arguments on something more than bluster.

Believing that humans have five senses has all the scientific backing of
believing in the tongue map.

~~~
TeMPOraL
I think 'lisper wasn't interested in a catalog of senses, but whether they're
"going to lead them to new physics that we haven't discovered". Once you
listed are less about physics/external world and more about internal status of
the body.

~~~
thaumasiotes
I don't think asserting that there's nothing more for us to discover is a good
method of determining whether we might discover something new.

If an alien sense relying on physics unknown to us were to come to our
attention, it seems likely to me that it would indeed lead us to discover that
new physics. But since we don't know whether physics like that exists or not,
we can't say whether such a sense could exist either. lisper has very clearly
claimed that such a sense cannot exist because there is no such physics; I
don't see how he could be interested in the question you state.

> Ones you listed are less about physics/external world and more about
> internal status of the body.

I'd say temperature, time, touch, hearing, sight, and smell are primarily
about the external world and proprioception, taste, and hunger are primarily
about the internal status of the body. That's really what distinguishes taste
from smell. Acceleration seems like a gray area.

~~~
acqq
> If an alien sense relying on physics unknown to us were to come to our
> attention, it seems likely to me that it would indeed lead us to discover
> that new physics. But since we don't know whether physics like that exists
> or not, we can't say whether such a sense could exist either.

But we do know enough physics already to explain _everything_ we can observe
that surrounds us, not with our senses alone but with the measurement devices
that we can construct.

The only physics that we can't measure and completely explain is that one that
is anyway inadequately reachable not only to us with out human senses but to
our measurement devices which already can measure changes in length 1000 times
the size of the proton, which happen on the 4 km length (see LIGO).

The only physics that remains to be known better are the effects that happen
on the galactic and intergalactic scales or inside of the black holes and
during the first picoseconds of the existence of the universe, or with the
particles that exist too short or interact too little to influence anything we
can observe:

[http://www.preposterousuniverse.com/blog/2010/09/23/the-
laws...](http://www.preposterousuniverse.com/blog/2010/09/23/the-laws-
underlying-the-physics-of-everyday-life-are-completely-understood/)

"The Laws Underlying The Physics of Everyday Life Are Completely Understood"

"there’s no question that the human goal of figuring out the basic rules by
which the easily observable world works was one that was achieved once and for
all in the twentieth century."

"You might question the “once and for all” part of that formulation, but it’s
solid. Of course revolutions can always happen, but there’s every reason to
believe that our current understanding is complete within the everyday realm.
Using the framework of quantum field theory — which we have no reason to doubt
in this regime — we can classify the kinds of new particles and forces that
could conceivably exist, and go look for them. It’s absolutely possible that
such particles and forces do exist, but they must be hidden from us somehow:
either the particles are too massive to be produced, or decay too quickly to
be detected, or interact too weakly to influence ordinary matter; and the
forces are either too weak or too short-range to be noticed. In any of those
cases, if they can’t be found by our current techniques, they are also unable
to influence what we see in our everyday lives."

~~~
FakeComments
There’s a ton of things we have no explanation for — superconductors, how
protons collide, a ton of things about material science, we’re still not great
at non-local effects, etc. That’s setting aside the doozy of “gravity and
particle physics say wildly incompatible things, and we’re not sure how to fix
that”.

And when I say “how protons collide”, I mean numbers from existing
accelerators don’t match predictions and they’re having to change models — and
all the fixes they can come up with (eg, elaborate swarms of virtual quarks)
still don’t fix the collision numbers.

There’s still a pretty poor understanding of 4D topology, and the effects and
possible knotting states play in non-local interactions. Microsoft for
instance theorizes that you can have 4D anyons, but no one is sure how to
build them. And it comes into play in more mundane ways when talking about
plasma physics or fluid dynamics, since the same mathematics governs stability
there.

You seem to be wildly overstating the success of science.

~~~
acqq
And then I'd claim you wildly understating the success, of course.
Superconductivity is not an effect that involves any "new physics" in the
sense of the necessity of changing the underlying theories: it's the typical
"emergent" property, and we know that modeling many of the "emergent"
properties is far away from our possibilities. Ditto with the material
science, or any other observations where "too many of the stuff known to us
interacts at the same time." It's not "we don't know" in the sense that the
basics will have to change it's "we don't know because there's too much to
model at once" like we can't reliably predict the weather 2 weeks in advance,
even if we understand the nature of the particles that produce the weather.

Edit: to answer your response below this post:

It's a [Citation needed] for you that the fundamentally "new physics" is
needed instead of reaching the limits of our instruments or the modeling
capability.

The second you mention is not something that contradicts what we measure, it
just that naively trying to combine the provably successful models that match
our measurements to produce "something more" outside of their domain really
doesn't work: and that of course doesn't have to work to claim that the models
do work for the things that they actually model, and which independently
correspond to the things we can "observe" (where "observe" includes using our
best measuring devices).

~~~
FakeComments
I disagree: I don’t think we know what features of the underlying model lead
to the emergence of things like superconductivity, and having to account for
that explicitly will demonstrate a new paradigm for analyzing the base
mechanics — which is likely to lead to a new interpretation and “new physics”.

I’ll also note you didn’t reply to two big ones:

They can’t predict proton on proton collisions in a hyper controlled tube
accurately.

They can’t predict how the two most established theories, each boasting dozens
of orders of magnitude of accuracy, interact.

------
ziont
what _is_ dark matter? is it the opposite of matter? how can it be called
matter when it doesn't exist?

or are these objects from higher dimensions as Michio Kaku postulates? that
galaxies are essentially in a bubble of dark matter preventing it from hurling
in every direction.

as well as the presence of dark matter in orbits, could it not be the space-
time curvature from the mass itself but from the encapsulating dark matter
around it?

I no very little of this subject so I can only ponder and fantasize.

~~~
krapp
Via Wikipedia[0]

    
    
        Dark matter is a hypothetical form of matter that is thought 
        to account for approximately 85% of the matter in the universe, 
        and about a quarter of its total energy density. 
    
        (...)
    
        Its presence is implied in a variety of astrophysical 
        observations, including gravitational effects that 
        cannot be explained unless more matter is present 
        than can be seen. 
    

Also, since it will inevitably come up as it always does in threads about dark
matter or dark energy , here is an article[1] and related[2] HN thread arguing
the theoretical justifications behind the existence of dark matter, what is
known or can be inferred about its properties and why chances are no one
missed whatever simple solution you can think of, like "maybe it's just normal
matter but they can't see it because it's far away" or "maybe it's just black
holes" and why it's also not entirely hubris or ignorance on the part of the
scientific community.

[0][https://en.wikipedia.org/wiki/Dark_matter](https://en.wikipedia.org/wiki/Dark_matter)

[1][https://medium.com/starts-with-a-bang/this-is-the-real-
reaso...](https://medium.com/starts-with-a-bang/this-is-the-real-reason-we-
havent-directly-detected-dark-matter-3d04021b314e)

[2][https://news.ycombinator.com/item?id=18207276](https://news.ycombinator.com/item?id=18207276)

~~~
rjf72
The article you link there does not mention the SISSA discovery of 2016 [1].
In particular in mini-spiral galaxies there seems to be an unexpected, and
inexplicable, interaction between dark and visible matter. This falsifies the
primary prediction put forth in that medium article. And in general this issue
is one that poses a critical problem for dark matter largely because it cannot
just be massaged into the model.

And that last point is really the problem with model based physics. They are
really really hard to falsify which can provide certainty through inertia. For
instance take the heliocentric vs geocentric earth. The geocentric view (that
the Earth was the center upon which everything rotated) was based upon a
model. It started out fairly simple and intuitive. But then we kept coming
upon ever more issues. For instance if everything else rotates around Earth
then that must mean other planets travel in sort of 'swirly' type patterns
that we see nowhere else in physics. Well, okay - why not. Hmm it also turns
out that some planets, such as Mercury, need to just magically stop in their
orbit and start going backwards at some point. Again, it's a model that we
can't really falsify so okay - why not.

And it absorbs really bizarre observation after another. The only way to
refute it was ultimately to be able to see 'through the eyes of god' that
geocentricism was wrong. This was not hubris or ignorance on part of the
scientific community. It was inertia. Hundreds of years scientific study was
built upon the assumption of a geocentric Earth. Astrology was a scholarly
pursuit, at least as reputable as psychology is today, developed over
centuries. And it was 100% dependent upon the geocentric model. We've
rewritten history to blame geocentricism on the church alone, but there was
far more in play there. Going against the geocentric model meant having the
arrogance to call numerous well reputed fields completely wrong, to completely
discredit and repudiate the work of the most brilliant minds of the times, and
to basically say you somehow know better than hundreds of years of work and
pretty much everybody else.

No, it's certainly not hubris that drives inertia. It's the lack thereof.
Einstein's theory of relativity sounds absolutely insane. It took the sort of
man who would go on to condescendingly mock quantum entanglement as "spooky
action at a distance" to have the sort of ego and self confidence, bordering
on hubris, to be able to not only consider such possibilities but to spend
years of countless effort refining and developing it. Much of this done when
he, unable to find a professorial position, was working in a patent office -
no less! Indeed if we have any bias in play, I'd expect it's rather a
contagion of humility driven by the exponential growth in complexity.

If anything, the arrogance would come in the form of an aggressive disregard
for alternatives. See the practically militant response to things such as MOND
[2] hypotheses. It still suffers many problems, as does dark matter, but
remains a viable alternative hypothesis which remains rather unexplored. Of
course there is a practical issue there. Since nobody expects things such as
MOND to be correct, which it probably is not, then spending years proving that
is effectively wasted. By contrast as most people expect dark matter to be
correct, proving it right _or_ wrong would be an achievement worthy of a trip
to Stockholm. It means pursuing MOND (or other alternatives) is a very
difficult choice, in terms of career progression and prospects. Scientific
inertia is a problem with no clear solution.

[1] - [https://phys.org/news/2016-12-unexpected-interaction-dark-
or...](https://phys.org/news/2016-12-unexpected-interaction-dark-ordinary-
mini-spiral.html)

[2] -
[https://en.wikipedia.org/wiki/Modified_Newtonian_dynamics](https://en.wikipedia.org/wiki/Modified_Newtonian_dynamics)

------
ccvannorman
Why is every single comment here being downvoted? I think many of them raise
valid points and discussions; I, too, have always been suspicious of "dark
matter" and have always looked at other possible explanations, such as "it
appears there is matter/gravity there from our vantage point, but with a
broader perspective/more complete picture we might see that { space time
curves differently at the local, galaxy, intergalaxy scale (for example)}".

~~~
magicalhippo
You make it sound like physicists haven't tried looking for alternative
explanations.

Faced with our many, varied observations there are two choices: either general
relativity is wrong at larger scales, or there's some stuff out there that
doesn't interact with light or much of anything else.

Maybe it's a combination of both, but to begin with it's usually a good idea
assume the simpler alternative that it's just one of them.

Some physicists are looking at changing general relativity. MOND[1] is just a
modification of Newton's law, so while it does reproduce the galaxy rotation
curve observations it doesn't really explain anything in the same way GR does,
and it's also non-relativistic which is pretty much a showstopper. There are
efforts to make a relativistic MOND-like theory, such as TeVeS[2], but so far
nothing has stood up. Some have considered that maybe quantum gravitational
effects[3] reproduce the dark matter observations, but that approach also seem
to have problems.

Your example implies a modification of GR. It appears to be very difficult to
modify GR at large scales while conforming to all the observations which
validate plain GR. So a good alternative guess is that there's something
matter-like out there we can't see. Doing so, physicists have considered
MACHOs[4], and they're currently searching for WIMPs[5], sterile neutrinos[6]
and axions[7] to name a few candidate particles.

If some new theory comes along which supersedes GR, explains all the things
plain GR can while also explaining the dark matter observations, then it would
be welcomed and embraced by the physics community. Until then, physicists are
looking in the direction they feel is the most promising one.

[1]:
[https://en.wikipedia.org/wiki/Modified_Newtonian_dynamics](https://en.wikipedia.org/wiki/Modified_Newtonian_dynamics)
[2]:
[https://en.wikipedia.org/wiki/Tensor%E2%80%93vector%E2%80%93...](https://en.wikipedia.org/wiki/Tensor%E2%80%93vector%E2%80%93scalar_gravity)
[3]:
[https://en.wikipedia.org/wiki/Entropic_gravity](https://en.wikipedia.org/wiki/Entropic_gravity)
[4]:
[https://en.wikipedia.org/wiki/Massive_compact_halo_object](https://en.wikipedia.org/wiki/Massive_compact_halo_object)
[5]:
[https://en.wikipedia.org/wiki/Weakly_interacting_massive_par...](https://en.wikipedia.org/wiki/Weakly_interacting_massive_particles)
[6]:
[https://en.wikipedia.org/wiki/Sterile_neutrino](https://en.wikipedia.org/wiki/Sterile_neutrino)
[7]:
[https://en.wikipedia.org/wiki/Axion](https://en.wikipedia.org/wiki/Axion)

------
perseusprime11
IMO, nothing is certain until we arrive at the boundary of universe
creation/expansion. This is where all of the real stuff is taking place. Until
then, it will be mostly theories and opinions.

~~~
squirrelicus
Conflating theory and opinion is a bad category error. You're going to have to
learn to accept that nothing outside the realm of mathematical proof is
certain. Not even Cell Theory is certain.

