
Bizarre Particles Keep Flying Out of Antarctica's Ice - daegloe
https://www.livescience.com/63692-standard-model-broken-supersymmetry-new-physics.html
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crazynick4
If I understand correctly, these particles are entering the earth from space
around, say, the North Pole, and the coming out the other side in Antarctica?

If so, is it only out of Antarctica? Would that mean they are coming from a
specific direction in space?

Why can't we observe them simply as they come out of space? Is there something
about the process of moving through the earth that makes them more detectable?

These may be stupid questions, feel free to vote this down..

Edit: if I understand correctly it seems like it's happenstance and ANITA just
happened to be above Antarctica when the cosmic rays shot up through it on
those particular occasions, I think

~~~
Gibbon1
I think it's because both detectors are using the deep ice sheet as part of
neutrino detection experiments.

ANITA is listening for Askaryan radiation created by neutrino's traveling
through ice (from the wiki, I know as much as you). And IceCube is looking for
flashes of light created when a neutrino interacts with ice.

~~~
cozzyd
Disclaimer: I work on ANITA. Also I need to go to bed, so I'm writing this
really fast so it probably doesn't make sense.

ANITA is a radio telescope attached to a balloon looking for broaband
impulsive radio emission in Antarctica.

The main purpose is to look for the Askaryan emission from neutrinos
interacting in the ice. The Askaryan emission is just the coherent version of
the same process (Cerenkov radiation) that produces the flashes of light in
IceCube (basically at long wavelengths you can't resolve the charges in a
cascade and see a fast moving current density-- there's a negative charge
excess because positrons can annihilate with atomic electrons). To detect this
Askaryan emission, you need a dense dielectric material (if not dense, no
target mass, if not dielectric, then RF won't propagate). Antarctica happens
to be both the place you do long duration ballooning (due to all-day sunlight
and favorable wind patterns that keep you over land) and the place with the
most ice.

However, the events discussed here were produced by another channel. ANITA can
also see RF emission from cosmic-ray extensive air showers (EAS). The RF
emission here mostly comes from the splitting of charges in the showers by the
Earth's magnetic field. Because in Antarctica, the magnetic field is
approximately vertical, this produces horizontally polarized emission. Because
ANITA is so high up (~40 km), EAS development from cosmic rays occurs below
the payload, so the most common way for us to observe EAS's from cosmic rays
is for the emission to bounce off the ice (because it's very forward-beamed).
We can also see atmosphere-skimming showers that miss the ice entirely. As
expected, the events that bounce off the ice have a polarity flip compared to
the events that miss the ice.

The strange events discussed here look like EAS's from air showers, but the RF
emission clearly points at the ice and there is no polarity flip from
reflection, so the events look like very-energetic upward going air showers.
There's no good way to explain upward going air showers in the Standard Model
at these energies and observed angle (at lower energies or more grazing
angles, tau neutrinos make it through the earth, which can decay to make
upward-going air showers). So either there is something wrong with the
measurement (we can't think of anything, but we're trying!), we got really
unlucky with anthropogenic backgrounds (we think this is very unlikely), or
there might be some new physics.

For this detection channel, there isn't too much special about Antarctica,
just that we're on a balloon looking down so we can see stuff coming from
below. The ice could potentially offer a slight enhancement compared to rock,
but that's probably not so important. Other observatories looking for upward
going showers from tau neutrinos (Pierre Auger) only look at very grazing
incidence. There are proposals using fluorescence instead of radio emission
(e.g. JEM-EUSO, and the SPB-EUSO balloon mission) that could do more or less
the same thing.

~~~
dukwon
> For this detection channel, there isn't too much special about Antarctica

What about for the Askaryan channel?

~~~
cozzyd
For the Askaryan channel you want a dense dielectric material (dense to have a
big target, dielectric so tht radio can propagate). On Earth, that means
glacial ice, sand or salt. Antarctica has a lot of ice.

~~~
dukwon
Is sea water unsuitable?

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wnoise
Yes, it's pretty much the opposite of a dielectric. It's a good conductor with
mobile charges, and cannot support any polarization.

~~~
dukwon
But it's good enough for ANTARES/KM3NET to see Cherenkov light, which I
believe requires a dielectric medium.

~~~
cozzyd
The problem is that radio doesn't propagate well in sea water (since it's
conductive) so you can't observe the interaction from far away in the radio.

~~~
dukwon
Gotcha, thanks.

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DavidSJ
I ask in ignorance, but: could these particles actually have come from space
in the normal way (i.e. from above the South Pole) and then just been
reflected back up from several meters or so below the surface? That would, on
its face, seem to resolve the question about strong vs. weak interaction:
they’d be strongly interacting particles that happened to interact and
ricochet straight back.

~~~
cozzyd
Disclaimer: I work on ANITA

The particles can't be reflected like that. We do see reflected radio emission
from (presumably) cosmic ray air showers, but the polarity of the signal
undergoes a sign flip on reflection. These signals are peculiar because they
are definitely coming from the ice but don't have the sign flip one would
expect for a reflection.

~~~
DavidSJ
Thanks for the answer! Apologies if this question betrays my ignorance
further, but what would happen if a signal were reflected twice? Would the
polarity flip back?

~~~
cozzyd
Yeah, or if it reflected off an interface going from high refraction index to
low (e.g. reflecting off an under-ice cavern or something). These are
possibilities, but 1) the reflection is far away, so for this to be coherent,
it probably must be some massive feature, and 2) ANITA also had a trailing
balloon with a calibration pulser from which we could observe both direct and
reflected pulses, and from that pulser, we never saw evidence of the reflected
pulses not being flipped in polarity. Of course, that did not probe every
region of ice and all incident angles, but it seems like if such a strange
reflection were likely, we likely would have seen it there.

Nonetheless, we are working on simulating reflections off various ice models
to see if we can come up with a plausible optics explanation (like
pathological sastrugi).

~~~
bacon_waffle
> pathological sastrugi

I think someone just named the next big Ice band.

edit: Folks who work in Antarctica often refer to it as "The Ice".

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jakeogh
paper:
[https://arxiv.org/pdf/1603.05218.pdf](https://arxiv.org/pdf/1603.05218.pdf)

~~~
mhandley
That's the 2016 Anita paper. There's also a newer Anita paper:
[https://arxiv.org/abs/1803.05088](https://arxiv.org/abs/1803.05088). The new
paper described in the article is this one:
[https://arxiv.org/abs/1809.09615](https://arxiv.org/abs/1809.09615)

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audunw
Ah, must be the second Stargate ;)

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Zenst
What angle are these particles hitting the detector as it may well be possible
these are particles are not traveling thru the entire planet and just a
traveling in a chord (a line thru a circle that does not pass thru the centre)
and as such, traveling thru far less of the planet.

Then there is the aspect that due to the size and the stated interaction with
other matter that they are deflected from their original trajectory and could
very well appear to be arising from directly below, giving the appearance of
passing right thru the planet when they are not.

So very much possibly explained with what we already know about said
particles.

~~~
cozzyd
Disclaimer: I work on ANITA

The two relevant events had RF emission from 27 and 35 degrees below the
horizontal. If interpreted as emission from upward-going EAS, then the
particle would be within a degree or so of that. So they don't go all the way
through the Earth, but through a chord long enough that, if our shower energy
estimate (which, admittedly, is fraught with peril, we have an order of
magnitude errors on that), no standard model particle could have made it
through (yes, at high energies, the Earth is opaque to neutrinos).

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deytempo
It’s obviously a UFO buried under the ice. Molder proved they are down there.

~~~
cozzyd
That's where GWAR came from, right?

~~~
MisterTea
If a certain Mr. Martini was spotted in the vicinity who is also in possession
of large quantity of crack cocaine, then yes.

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fabatka
_> and it could break physics as we know it._

Stopped reading there. I hate that a lot of pop-science articles suggest that
the foundations of natural sciences are so shaky that a new finding can turn
them upside-down. I've lived together with 50-60 social scientists in a small
community during my student years, and I found that they don't have the
slightest idea about how thoroughly e.g. special and general relativity have
been tested in controlled experiments and every day when they use gps in their
smartphones. For them these theories may be true, but who knows? I find it
really sad that media that are supposed to bring sciences closer to non-
scientists fail this way.

EDIT: added last sentence

~~~
kowdermeister
> a lot of pop-science articles suggest that the foundations of natural
> sciences are so shaky that a new finding can turn them upside-down

Dark matter, Dark energy, The cosmological constant problem [1], Quantum
entanglement, Quantum gravity...

[1]
[https://en.wikipedia.org/wiki/Cosmological_constant_problem](https://en.wikipedia.org/wiki/Cosmological_constant_problem)

The foundations are shaky. Of course it's an easy rhetoric tool to use by
journalists, but often they are not wrong, if those claims turn out to be
true.

~~~
whatshisface
That's not so much a crack in the foundation as it is a patch of dirt next to
the foundation.

To get an idea of what happens to old physics when new physics is discovered,
realize that Newton's laws are still correct, and can be derived from QM.
That's what you get when you do a good job of actually checking the truth with
experiments. All theories have implicit tolerances embedded within the known
precision of the experiments used to confirm them, and with these tolerances
you can say "Newton's laws are right" without denying other, finer details.
Similarly, scientists 1000 years from now will agree with everything we
presently know about the Standard Model, because all of our beliefs are
tempered by how closely we know our experiments are looking.

> _Quantum entanglement_

I should add that entanglement isn't "shaky" at all, it was predicted from the
start and has been observed in countless experiments to date.

~~~
andars
Borrowing from an a old comment of mine:

On one hand, on some scales, Newtonian mechanics is correct "enough" to give
results that work, and so in that sense it is just incomplete in that its
domain is restricted. On the other, relativity and QM change everything. These
new theories may reduce to Newtonian mechanics given certain assumptions, but
Newtonian physics assumes things about the structure of spacetime that are
fundamentally incorrect (e.g. velocity is not additive). In this sense, one
can fairly say that Newton's mechanics are not just incomplete or missing some
fine details, but wrong.

I think there is more to the foundations than just the best numbers we can
come up with for a given experiment. Our numbers for the gravitational
constant, for example, are pretty similar (if more precise) to the numbers in
1891, but the setting in which that number is completely changed. There is no
aether, no absolute space, velocities don't add (even though it's "mostly"
right on most scales we experience and measure, it is false), space and time
get mixed up, etc. Those were all pretty foundational ideas just over a
hundred years ago.

~~~
whatshisface
> _There is no aether, no absolute space, velocities don 't add_

There are two categories of things in that list: statements that had
implications beyond what they had confirmed (the medium of light, the
absoluteness of space) and an approximation (the addition of velocities.)
Unsurprisingly the metaphysical interpretation of physics has not stood up to
refinements in physics. The physics, however, remains true to within the
bounds they knew. Likewise, the _interpretation_ of physics is likely to
change quite a bit over the next 1000 years, even 100. That's why you should
never put too much stock in pop-sci articles that try to tell you that the
universe is made of this-or-that. Fortunately on the philosophical side we now
all realize that the interpretations are just humanizations of the knowledge
itself, and are not knowledge themselves.

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torgian
Maybe it's alien transmissions that are using the Earth as a gigantic radio
booster. XD

one can dream...

~~~
JBReefer
Rogue ICMP packets performing a reflection attack on those schmucks on Mars

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M_Bakhtiari
Ultraghiaccio, perhaps?

Romano Scarpa fans should know what I'm talking about.

~~~
M_Bakhtiari
Hmm...looks like I'd better stick to yankee cultural references in the future.

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negamax
Isn't Earth like a giant rotating magnet? That should create some weird
things. Wears sci-fi cap!

