Dancing Swarf Galaxies

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Dancing dwarf galaxies deepen dark matter mystery

Surprising alignment between small satellites of the galaxy Centaurus A cha=
llenges the standard model of cosmology

SHANNON STIRONE,=C2=A0SCIENTIFIC AMERICAN

This article was originally published by=C2=A0Scientific American.Many larg=
e galaxies =E2=80=94 our Milky Way among them =E2=80=94 are orbited by a re=
tinue of smaller, fainter companions: dwarf galaxies. Some are probably nea=
rly as old as the universe itself, isolated islands of ancient stars that n=
ever managed to glom onto a larger galaxy; others are younger, born from th=
e shredded remains of bigger galaxies that collided and ripped one another =
apart. Regardless of whether any given dwarf galaxy is a primordial buildin=
g block or a late-stage leftover from a galactic merger, studying these dim=
inutive objects is arguably one of the best ways to learn about how galaxie=
s and other large cosmic structures emerge, interact and grow. And studying=
 the large-scale structures in turn is one of the best ways we have of unde=
rstanding the fundamental rules of the universe we live in.In some respects=
, watching dwarf galaxies orbiting their larger hosts is rather like watchi=
ng bees humming around a hive. Dwarfs, like bees, appear aimless in their=
=C2=A0flights=E2=80=94 up and down, left and right, with no obvious rhyme o=
r reason. But both have a hidden order. Bees surf around their hives on win=
d currents carrying the scents of flowers and pheromones, and the orbits of=
 dwarf galaxies are dictated in part by something even more mysterious: the=
 gravitational pull of dark matter. This theoretical, invisible substance i=
s more felt than seen, for it emits no light; the only way we infer its exi=
stence is by how it warps the space around it. Crude=C2=A0maps=C2=A0of its =
distribution indicate dark matter forms a sort of cosmic web, where galaxie=
s large and small are gravitationally glued to filaments and sheets of dark=
 matter. =E2=80=9CWe have this web of dark matter that feeds the host galax=
y from all angles and=C2=A0directions, and that=E2=80=99s why we find so ma=
ny different orbits and motions of these dwarf galaxies,=E2=80=9D says Oliv=
er M=C3=BCller, a PhD candidate at the University of Basel.
In a new study published Thursday in=C2=A0Science, M=C3=BCller and colleagu=
es charted how 16 dwarfs moved around the =E2=80=9Cbeehive=E2=80=9D of Cent=
aurus A, a large galaxy upward of 10 million light-years distant from the M=
ilky Way. They found that rather than following random orbits, 14 of the dw=
arfs of Centaurus A are surprisingly aligned and coplanar, that is, they sh=
are the same orbital plane =E2=80=94 a bit like bees flying in a well-order=
ed ring around a hive. The puzzling=C2=A0configuration=C2=A0=E2=80=94 which=
 M=C3=BCller=E2=80=99s simulations suggest only have a 0.5 percent probabil=
ity of occurring by happenstance =E2=80=94 has some scientists questioning =
just how much they understand the behavior and environment around these sat=
ellites. If seen around many other galaxies across the universe, M=C3=BClle=
r says, such bizarrely coplanar dwarfs could even challenge cosmologists=E2=
=80=99 =E2=80=9CLambda cold dark matter=E2=80=9D (LCDM) conception of the u=
niverse =E2=80=94 the standard model used to explain how galaxies and galax=
y clusters emerge and evolve.But although the new study emphasizes the rari=
ty of aligned coplanar dwarf galaxies, such configurations have been observ=
ed before. In fact, prevailing theories suggest that one out of every 10 dw=
arf galaxies should possess some kind of alignment; at least that=E2=80=99s=
 what computer simulations suggest.What is unique about this particular ali=
gnment is =E2=80=9Cthis is the first example of this kind of configuration =
seen outside of our local (galactic) group, so that=E2=80=99s quite interes=
ting,=E2=80=9D says Carlos Frenk, a cosmologist at Durham University in Eng=
land. Coplanar dwarf galaxies have been found for the Milky Way and Androme=
da, Frenk notes, but the 14 around Centaurus A are the first observed circl=
ing a more distant galaxy.In their study, M=C3=BCller and his team argue th=
at if coplanar alignments of dwarf galaxies are widespread, this would pose=
 a worthy challenge to the LCDM model =E2=80=94 which predicts a random dis=
tribution of dwarfs. Finding many coplanar arrangements would suggest, in s=
hort, our already limited understanding of dark matter is even more incompl=
ete than previously appreciated. Frenk, for one, is not entirely convinced,=
 pointing out the LCDM model remains in excellent agreement with the vast m=
ajority of decades=E2=80=99 worth of observations. =E2=80=9CThe standard mo=
del works quite well,=E2=80=9D Frenk says. =E2=80=9CWhy would it just stop =
in an instant? It=E2=80=99s interesting, but not a challenge that threatens=
 the cosmological paradigm at this point.=E2=80=9DUnfortunately, taking a m=
ore complete=C2=A0census=C2=A0of dwarf galaxies would take decades. Observi=
ng the movements of dwarf galaxies is extremely nuanced, in large part beca=
use we can more easily measure the speeds of far-distant objects that move =
either away from or toward us in the sky, rather than those that move acros=
s the celestial sphere. And as their name implies, dwarf galaxies are extre=
mely small and dim, making their discoveries even more of a challenge the f=
arther out one looks from the Milky Way. All these effects act to bias the =
observational data, muddying the waters so that a clear trend either of cop=
lanarity or of disorder becomes hard to see. The only solution is to find a=
nd study dwarf galaxies, near and far, using multiple overlapping and time-=
consuming methods.Meanwhile, intriguing observations like these might do mo=
re to actually confirm the success of the LCDM model than to replace it. Mi=
chael Boylan-Kolchin, an astrophysicist at The University of Texas at Austi=
n and author of an accompanying commentary in=C2=A0Science, says the standa=
rd model has overcome similar challenges before. =E2=80=9CThe LCDM has face=
d many tests and is still the standard cosmological model; I expect the sam=
e will be true in the case of satellite planes,=E2=80=9D he says. =E2=80=9C=
However, I also think it is essential to fully investigate all potential in=
consistencies. It is the only way we increase our confidence in theories or=
, in rare cases, find the flaws that demand fundamental revisions.=E2=80=9D=
As a part of his dissertation work, M=C3=BCller plans to spend time in the =
upcoming months using the Dark Energy Camera in Chile to study the Centauru=
s A system with the hopes of finding more dwarf satellites. Another dozen o=
r so in nonplanar orbits could make the reported trend disappear. For now t=
hough, he is excited about this oddity, because it may actually be the norm=
. =E2=80=9CThese systems aren=E2=80=99t just an outlier =E2=80=94 they look=
 like they=E2=80=99re more common. I think we have to take this very seriou=
sly=E2=80=A6. I want us to do further studies of this structure. I want to =
show that this isn=E2=80=99t just a coincidence.=E2=80=9D
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 deepen dark matter mystery</h1><span data-comment=3D"post title end" style=
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prising alignment between small satellites of the galaxy Centaurus A challe=
nges the standard model of cosmology</h2><h2 style=3D"box-sizing: border-bo=
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yui_3_16_0_ym19_1_1518396169439_8042"><a target=3D"_blank" rel=3D"noopener"=
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tyle=3D"box-sizing: border-box; border: 0px; font-family: inherit; font-sty=
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yui_3_16_0_ym19_1_1518396169439_8103">This article was originally published=
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erit; outline: 0px; padding-bottom: 18px; vertical-align: baseline; line-he=
ight: 1.5; word-break: break-word;" id=3D"yui_3_16_0_ym19_1_1518396169439_8=
111"><a href=3D"http://www.scientificamerican.com/" style=3D"box-sizing: bo=
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=3D"yui_3_16_0_ym19_1_1518396169439_8112"><img src=3D"https://media.salon.c=
om/2012/08/image002.jpeg" alt=3D"Scientific American" style=3D"box-sizing: =
border-box; max-width: 100%; min-height: auto; margin: 0px 10px 0px 0px;" i=
d=3D"yui_3_16_0_ym19_1_1518396169439_8113" data-id=3D"939345d2-4532-f63e-d6=
6d-ff0a2f8f14b5" class=3D"img-overlay-selected"></a></div></div><div data-n=
ode=3D"node-2" style=3D"box-sizing: border-box; border: 0px; font-family: i=
nherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0p=
x; padding: 0px; vertical-align: baseline;" id=3D"yui_3_16_0_ym19_1_1518396=
169439_8114"><div style=3D"box-sizing: border-box; font-size: 1em; border: =
0px; font-style: inherit; outline: 0px; padding-bottom: 18px; vertical-alig=
n: baseline; line-height: 1.5; word-break: break-word;" id=3D"yui_3_16_0_ym=
19_1_1518396169439_8115">Many large galaxies =E2=80=94 our Milky Way among =
them =E2=80=94 are orbited by a retinue of smaller, fainter companions: dwa=
rf galaxies. Some are probably nearly as old as the universe itself, isolat=
ed islands of ancient stars that never managed to glom onto a larger galaxy=
; others are younger, born from the shredded remains of bigger galaxies tha=
t collided and ripped one another apart. Regardless of whether any given dw=
arf galaxy is a primordial building block or a late-stage leftover from a g=
alactic merger, studying these diminutive objects is arguably one of the be=
st ways to learn about how galaxies and other large cosmic structures emerg=
e, interact and grow. And studying the large-scale structures in turn is on=
e of the best ways we have of understanding the fundamental rules of the un=
iverse we live in.</div></div><div data-node=3D"node-4" style=3D"box-sizing=
: border-box; border: 0px; font-family: inherit; font-style: inherit; font-=
weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: b=
aseline;" id=3D"yui_3_16_0_ym19_1_1518396169439_8116"><div style=3D"box-siz=
ing: border-box; font-size: 1em; border: 0px; font-style: inherit; outline:=
 0px; padding-bottom: 18px; vertical-align: baseline; line-height: 1.5; wor=
d-break: break-word;" id=3D"yui_3_16_0_ym19_1_1518396169439_8117">In some r=
espects, watching dwarf galaxies orbiting their larger hosts is rather like=
 watching bees humming around a hive. Dwarfs, like bees, appear aimless in =
their&nbsp;<nobr style=3D"box-sizing: border-box; font-size: inherit;" id=
=3D"yui_3_16_0_ym19_1_1518396169439_8118"><a href=3D"https://www.salon.com/=
2018/02/11/dancing-dwarf-galaxies-deepen-dark-matter-mystery_partner/#" sty=
le=3D"box-sizing: border-box; font-family: inherit; font-style: inherit; ou=
tline-style: initial; outline-width: 0px; vertical-align: baseline; border-=
width: 0px 0px 1px !important; border-top-style: initial !important; border=
-right-style: initial !important; border-bottom-style: solid !important; bo=
rder-left-style: initial !important; border-top-color: initial !important; =
border-right-color: initial !important; border-bottom-color: rgb(28, 125, 2=
55) !important; border-left-color: initial !important; border-image: initia=
l !important; font-size: inherit !important; padding-bottom: 1px !important=
; color: rgb(28, 125, 255) !important; display: inline !important;" id=3D"y=
ui_3_16_0_ym19_1_1518396169439_8119">flights</a></nobr>=E2=80=94 up and dow=
n, left and right, with no obvious rhyme or reason. But both have a hidden =
order. Bees surf around their hives on wind currents carrying the scents of=
 flowers and pheromones, and the orbits of dwarf galaxies are dictated in p=
art by something even more mysterious: the gravitational pull of dark matte=
r. This theoretical, invisible substance is more felt than seen, for it emi=
ts no light; the only way we infer its existence is by how it warps the spa=
ce around it. Crude&nbsp;<nobr style=3D"box-sizing: border-box; font-size: =
inherit;" id=3D"yui_3_16_0_ym19_1_1518396169439_8120"><a href=3D"https://ww=
w.salon.com/2018/02/11/dancing-dwarf-galaxies-deepen-dark-matter-mystery_pa=
rtner/#" style=3D"box-sizing: border-box; font-family: inherit; font-style:=
 inherit; outline-style: initial; outline-width: 0px; vertical-align: basel=
ine; border-width: 0px 0px 1px !important; border-top-style: initial !impor=
tant; border-right-style: initial !important; border-bottom-style: solid !i=
mportant; border-left-style: initial !important; border-top-color: initial =
!important; border-right-color: initial !important; border-bottom-color: rg=
b(28, 125, 255) !important; border-left-color: initial !important; border-i=
mage: initial !important; font-size: inherit !important; padding-bottom: 1p=
x !important; color: rgb(28, 125, 255) !important; display: inline !importa=
nt;" id=3D"yui_3_16_0_ym19_1_1518396169439_8121">maps</a></nobr>&nbsp;of it=
s distribution indicate dark matter forms a sort of cosmic web, where galax=
ies large and small are gravitationally glued to filaments and sheets of da=
rk matter. =E2=80=9CWe have this web of dark matter that feeds the host gal=
axy from all angles and&nbsp;<nobr style=3D"box-sizing: border-box; font-si=
ze: inherit;" id=3D"yui_3_16_0_ym19_1_1518396169439_8122"><a href=3D"https:=
//www.salon.com/2018/02/11/dancing-dwarf-galaxies-deepen-dark-matter-myster=
y_partner/#" style=3D"box-sizing: border-box; font-family: inherit; font-st=
yle: inherit; outline-style: initial; outline-width: 0px; vertical-align: b=
aseline; border-width: 0px 0px 1px !important; border-top-style: initial !i=
mportant; border-right-style: initial !important; border-bottom-style: soli=
d !important; border-left-style: initial !important; border-top-color: init=
ial !important; border-right-color: initial !important; border-bottom-color=
: rgb(28, 125, 255) !important; border-left-color: initial !important; bord=
er-image: initial !important; font-size: inherit !important; padding-bottom=
: 1px !important; color: rgb(28, 125, 255) !important; display: inline !imp=
ortant;" id=3D"yui_3_16_0_ym19_1_1518396169439_8123">directions</a></nobr>,=
 and that=E2=80=99s why we find so many different orbits and motions of the=
se dwarf galaxies,=E2=80=9D says Oliver M=C3=BCller, a PhD candidate at the=
 University of Basel.</div></div></div></div></div></div><div style=3D"box-=
sizing: border-box; border: 0px; font-family: Roboto, sans-serif; font-size=
: 16px; margin: auto; outline: 0px; padding: 0px; vertical-align: baseline;=
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169439_8125"><div style=3D"box-sizing: border-box; border: 0px; font-family=
: inherit; font-style: inherit; font-weight: inherit; margin: auto 300px au=
to auto; outline: 0px; padding: 20px 92px 0px 175px; vertical-align: baseli=
ne; position: relative; width: auto; max-width: 1186px;" id=3D"yui_3_16_0_y=
m19_1_1518396169439_8126"><br></div></div></div><div data-obwidget-id=3D"AR=
_8" style=3D"box-sizing: border-box; border: 0px; font-family: Roboto, sans=
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: auto; max-width: 1186px;" id=3D"yui_3_16_0_ym19_1_1518396169439_8127"><di=
v data-src=3D"/2018/02/11/dancing-dwarf-galaxies-deepen-dark-matter-mystery=
_partner/" data-widget-id=3D"AR_8" data-ob-template=3D"salon" data-ob-mark=
=3D"true" data-browser=3D"chrome" data-os=3D"win32" data-dynload=3D"" data-=
idx=3D"0" style=3D"box-sizing: border-box; border: 0px; font-family: inheri=
t; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; pa=
dding: 0px; vertical-align: baseline;" id=3D"yui_3_16_0_ym19_1_151839616943=
9_8128"><div data-dynamic-truncate=3D"true" style=3D"box-sizing: border-box=
; border-width: 2px 0px; border-top-style: solid; border-right-style: initi=
al; border-bottom-style: solid; border-left-style: initial; border-top-colo=
r: black; border-right-color: initial; border-bottom-color: black; border-l=
eft-color: initial; border-image: initial; font-family: inherit; font-style=
: inherit; font-weight: inherit; margin: 15px 0px; outline: 0px; padding: 2=
5px 0px; vertical-align: baseline; position: relative; width: auto; min-wid=
th: 180px;" id=3D"yui_3_16_0_ym19_1_1518396169439_8129"><div style=3D"box-s=
izing: border-box; border: 0px; font-family: inherit; font-style: inherit; =
font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-ali=
gn: baseline;" id=3D"yui_3_16_0_ym19_1_1518396169439_8160"></div></div></di=
v></div><div style=3D"box-sizing: border-box; border: 0px; font-family: Rob=
oto, sans-serif; font-size: 16px; margin: auto; outline: 0px; padding: 0px;=
 vertical-align: baseline; max-width: 1563px; position: relative;" id=3D"yu=
i_3_16_0_ym19_1_1518396169439_8161"><div style=3D"box-sizing: border-box; b=
order: 0px; font-family: inherit; font-style: inherit; font-weight: inherit=
; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;" id=3D=
"yui_3_16_0_ym19_1_1518396169439_8162"><div style=3D"box-sizing: border-box=
; border: 0px; font-family: inherit; font-style: inherit; font-weight: inhe=
rit; margin: auto 300px auto auto; outline: 0px; padding: 20px 92px 0px 175=
px; vertical-align: baseline; position: relative; width: auto; max-width: 1=
186px;" id=3D"yui_3_16_0_ym19_1_1518396169439_8163"></div></div></div><div =
style=3D"box-sizing: border-box; border: 0px; font-family: Roboto, sans-ser=
if; font-size: 16px; margin: auto; outline: 0px; padding: 0px; vertical-ali=
gn: baseline; max-width: 1563px; position: relative;" id=3D"yui_3_16_0_ym19=
_1_1518396169439_8164"><div style=3D"box-sizing: border-box; border: 0px; f=
ont-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px=
; outline: 0px; padding: 0px; vertical-align: baseline;" id=3D"yui_3_16_0_y=
m19_1_1518396169439_8165"><div style=3D"box-sizing: border-box; border: 0px=
; font-family: inherit; font-style: inherit; font-weight: inherit; margin: =
auto 300px auto auto; outline: 0px; padding: 20px 92px 0px 175px; vertical-=
align: baseline; position: relative; width: auto; max-width: 1186px;" id=3D=
"yui_3_16_0_ym19_1_1518396169439_8166"><div style=3D"box-sizing: border-box=
; border: 0px; font-family: inherit; font-style: inherit; font-weight: inhe=
rit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;" id=
=3D"yui_3_16_0_ym19_1_1518396169439_8167"><div data-node=3D"node-6" style=
=3D"box-sizing: border-box; border: 0px; font-family: inherit; font-style: =
inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; ver=
tical-align: baseline;" id=3D"yui_3_16_0_ym19_1_1518396169439_8168"><div st=
yle=3D"box-sizing: border-box; font-size: 1em; border: 0px; font-style: inh=
erit; outline: 0px; padding-bottom: 18px; vertical-align: baseline; line-he=
ight: 1.5; word-break: break-word;" id=3D"yui_3_16_0_ym19_1_1518396169439_8=
169">In a new study published Thursday in&nbsp;<em style=3D"box-sizing: bor=
der-box; border: 0px; font-family: inherit; font-weight: inherit; margin: 0=
px; outline: 0px; padding: 0px; vertical-align: baseline;" id=3D"yui_3_16_0=
_ym19_1_1518396169439_8170">Science</em>, M=C3=BCller and colleagues charte=
d how 16 dwarfs moved around the =E2=80=9Cbeehive=E2=80=9D of Centaurus A, =
a large galaxy upward of 10 million light-years distant from the Milky Way.=
 They found that rather than following random orbits, 14 of the dwarfs of C=
entaurus A are surprisingly aligned and coplanar, that is, they share the s=
ame orbital plane =E2=80=94 a bit like bees flying in a well-ordered ring a=
round a hive. The puzzling&nbsp;<nobr style=3D"box-sizing: border-box; font=
-size: inherit;" id=3D"yui_3_16_0_ym19_1_1518396169439_8171"><a href=3D"htt=
ps://www.salon.com/2018/02/11/dancing-dwarf-galaxies-deepen-dark-matter-mys=
tery_partner/#" style=3D"box-sizing: border-box; font-family: inherit; font=
-style: inherit; outline-style: initial; outline-width: 0px; vertical-align=
: baseline; border-width: 0px 0px 1px !important; border-top-style: initial=
 !important; border-right-style: initial !important; border-bottom-style: s=
olid !important; border-left-style: initial !important; border-top-color: i=
nitial !important; border-right-color: initial !important; border-bottom-co=
lor: rgb(28, 125, 255) !important; border-left-color: initial !important; b=
order-image: initial !important; font-size: inherit !important; padding-bot=
tom: 1px !important; color: rgb(28, 125, 255) !important; display: inline !=
important;" id=3D"yui_3_16_0_ym19_1_1518396169439_8172">configuration</a></=
nobr>&nbsp;=E2=80=94 which M=C3=BCller=E2=80=99s simulations suggest only h=
ave a 0.5 percent probability of occurring by happenstance =E2=80=94 has so=
me scientists questioning just how much they understand the behavior and en=
vironment around these satellites. If seen around many other galaxies acros=
s the universe, M=C3=BCller says, such bizarrely coplanar dwarfs could even=
 challenge cosmologists=E2=80=99 =E2=80=9CLambda cold dark matter=E2=80=9D =
(LCDM) conception of the universe =E2=80=94 the standard model used to expl=
ain how galaxies and galaxy clusters emerge and evolve.</div></div><div dat=
a-node=3D"node-8" style=3D"box-sizing: border-box; border: 0px; font-family=
: inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline:=
 0px; padding: 0px; vertical-align: baseline;" id=3D"yui_3_16_0_ym19_1_1518=
396169439_8173"><div style=3D"box-sizing: border-box; font-size: 1em; borde=
r: 0px; font-style: inherit; outline: 0px; padding-bottom: 18px; vertical-a=
lign: baseline; line-height: 1.5; word-break: break-word;" id=3D"yui_3_16_0=
_ym19_1_1518396169439_8174">But although the new study emphasizes the rarit=
y of aligned coplanar dwarf galaxies, such configurations have been observe=
d before. In fact, prevailing theories suggest that one out of every 10 dwa=
rf galaxies should possess some kind of alignment; at least that=E2=80=99s =
what computer simulations suggest.</div></div><div data-node=3D"node-10" st=
yle=3D"box-sizing: border-box; border: 0px; font-family: inherit; font-styl=
e: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; =
vertical-align: baseline;" id=3D"yui_3_16_0_ym19_1_1518396169439_8175"><div=
 style=3D"box-sizing: border-box; font-size: 1em; border: 0px; font-style: =
inherit; outline: 0px; padding-bottom: 18px; vertical-align: baseline; line=
-height: 1.5; word-break: break-word;" id=3D"yui_3_16_0_ym19_1_151839616943=
9_8176">What is unique about this particular alignment is =E2=80=9Cthis is =
the first example of this kind of configuration seen outside of our local (=
galactic) group, so that=E2=80=99s quite interesting,=E2=80=9D says Carlos =
Frenk, a cosmologist at Durham University in England. Coplanar dwarf galaxi=
es have been found for the Milky Way and Andromeda, Frenk notes, but the 14=
 around Centaurus A are the first observed circling a more distant galaxy.<=
/div></div></div></div></div></div><div style=3D"box-sizing: border-box; bo=
rder: 0px; font-family: Roboto, sans-serif; font-size: 16px; margin: auto; =
outline: 0px; padding: 0px; vertical-align: baseline; max-width: 1563px; po=
sition: relative;" id=3D"yui_3_16_0_ym19_1_1518396169439_8177"><div style=
=3D"box-sizing: border-box; border: 0px; font-family: inherit; font-style: =
inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; ver=
tical-align: baseline;" id=3D"yui_3_16_0_ym19_1_1518396169439_8178"><div st=
yle=3D"box-sizing: border-box; border: 0px; font-family: inherit; font-styl=
e: inherit; font-weight: inherit; margin: auto 300px auto auto; outline: 0p=
x; padding: 20px 92px 0px 175px; vertical-align: baseline; position: relati=
ve; width: auto; max-width: 1186px;" id=3D"yui_3_16_0_ym19_1_1518396169439_=
8179"></div></div></div><div style=3D"box-sizing: border-box; border: 0px; =
font-family: Roboto, sans-serif; font-size: 16px; margin: 0px; outline: 0px=
; padding: 0px; vertical-align: baseline;" id=3D"yui_3_16_0_ym19_1_15183961=
69439_8180"><span data-comment=3D"carambola begin" style=3D"box-sizing: bor=
der-box; border: 0px; font-family: inherit; font-style: inherit; font-weigh=
t: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseli=
ne;" id=3D"yui_3_16_0_ym19_1_1518396169439_8181"></span><div style=3D"box-s=
izing: border-box; border: 0px; font-family: inherit; font-style: inherit; =
font-weight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-ali=
gn: baseline;" id=3D"yui_3_16_0_ym19_1_1518396169439_8182"><img height=3D"0=
" width=3D"0" alt=3D"" src=3D"https://pixel.watch/e03f" style=3D"box-sizing=
: border-box; max-width: 100%; min-height: auto; display: block;" id=3D"yui=
_3_16_0_ym19_1_1518396169439_8183" data-id=3D"985f9c52-df88-5678-578e-202cc=
f2cb5d0"></div><span data-comment=3D"carambola end" style=3D"box-sizing: bo=
rder-box; border: 0px; font-family: inherit; font-style: inherit; font-weig=
ht: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: basel=
ine;" id=3D"yui_3_16_0_ym19_1_1518396169439_8184"></span></div><div style=
=3D"box-sizing: border-box; border: 0px; font-family: Roboto, sans-serif; f=
ont-size: 16px; margin: auto; outline: 0px; padding: 0px; vertical-align: b=
aseline; max-width: 1563px; position: relative;" id=3D"yui_3_16_0_ym19_1_15=
18396169439_8185"><div style=3D"box-sizing: border-box; border: 0px; font-f=
amily: inherit; font-style: inherit; font-weight: inherit; margin: 0px; out=
line: 0px; padding: 0px; vertical-align: baseline;" id=3D"yui_3_16_0_ym19_1=
_1518396169439_8186"><div style=3D"box-sizing: border-box; border: 0px; fon=
t-family: inherit; font-style: inherit; font-weight: inherit; margin: auto =
300px auto auto; outline: 0px; padding: 20px 92px 0px 175px; vertical-align=
: baseline; position: relative; width: auto; max-width: 1186px;" id=3D"yui_=
3_16_0_ym19_1_1518396169439_8187"></div></div></div><div style=3D"box-sizin=
g: border-box; border: 0px; font-family: Roboto, sans-serif; font-size: 16p=
x; margin: auto; outline: 0px; padding: 0px; vertical-align: baseline; max-=
width: 1563px; position: relative;" id=3D"yui_3_16_0_ym19_1_1518396169439_8=
188"><div style=3D"box-sizing: border-box; border: 0px; font-family: inheri=
t; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px; pa=
dding: 0px; vertical-align: baseline;" id=3D"yui_3_16_0_ym19_1_151839616943=
9_8189"><div style=3D"box-sizing: border-box; border: 0px; font-family: inh=
erit; font-style: inherit; font-weight: inherit; margin: auto 300px auto au=
to; outline: 0px; padding: 20px 92px 0px 175px; vertical-align: baseline; p=
osition: relative; width: auto; max-width: 1186px;" id=3D"yui_3_16_0_ym19_1=
_1518396169439_8190"><div style=3D"box-sizing: border-box; border: 0px; fon=
t-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px; =
outline: 0px; padding: 0px; vertical-align: baseline;" id=3D"yui_3_16_0_ym1=
9_1_1518396169439_8191"><div data-node=3D"node-12" style=3D"box-sizing: bor=
der-box; border: 0px; font-family: inherit; font-style: inherit; font-weigh=
t: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseli=
ne;" id=3D"yui_3_16_0_ym19_1_1518396169439_8192"><div style=3D"box-sizing: =
border-box; font-size: 1em; border: 0px; font-style: inherit; outline: 0px;=
 padding-bottom: 18px; vertical-align: baseline; line-height: 1.5; word-bre=
ak: break-word;" id=3D"yui_3_16_0_ym19_1_1518396169439_8193">In their study=
, M=C3=BCller and his team argue that if coplanar alignments of dwarf galax=
ies are widespread, this would pose a worthy challenge to the LCDM model =
=E2=80=94 which predicts a random distribution of dwarfs. Finding many copl=
anar arrangements would suggest, in short, our already limited understandin=
g of dark matter is even more incomplete than previously appreciated. Frenk=
, for one, is not entirely convinced, pointing out the LCDM model remains i=
n excellent agreement with the vast majority of decades=E2=80=99 worth of o=
bservations. =E2=80=9CThe standard model works quite well,=E2=80=9D Frenk s=
ays. =E2=80=9CWhy would it just stop in an instant? It=E2=80=99s interestin=
g, but not a challenge that threatens the cosmological paradigm at this poi=
nt.=E2=80=9D</div></div><div data-node=3D"node-14" style=3D"box-sizing: bor=
der-box; border: 0px; font-family: inherit; font-style: inherit; font-weigh=
t: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseli=
ne;" id=3D"yui_3_16_0_ym19_1_1518396169439_8194"><div style=3D"box-sizing: =
border-box; font-size: 1em; border: 0px; font-style: inherit; outline: 0px;=
 padding-bottom: 18px; vertical-align: baseline; line-height: 1.5; word-bre=
ak: break-word;" id=3D"yui_3_16_0_ym19_1_1518396169439_8195">Unfortunately,=
 taking a more complete&nbsp;<nobr style=3D"box-sizing: border-box; font-si=
ze: inherit;" id=3D"yui_3_16_0_ym19_1_1518396169439_8196"><a href=3D"https:=
//www.salon.com/2018/02/11/dancing-dwarf-galaxies-deepen-dark-matter-myster=
y_partner/#" style=3D"box-sizing: border-box; font-family: inherit; font-st=
yle: inherit; outline-style: initial; outline-width: 0px; vertical-align: b=
aseline; border-width: 0px 0px 1px !important; border-top-style: initial !i=
mportant; border-right-style: initial !important; border-bottom-style: soli=
d !important; border-left-style: initial !important; border-top-color: init=
ial !important; border-right-color: initial !important; border-bottom-color=
: rgb(28, 125, 255) !important; border-left-color: initial !important; bord=
er-image: initial !important; font-size: inherit !important; padding-bottom=
: 1px !important; color: rgb(28, 125, 255) !important; display: inline !imp=
ortant;" id=3D"yui_3_16_0_ym19_1_1518396169439_8197">census</a></nobr>&nbsp=
;of dwarf galaxies would take decades. Observing the movements of dwarf gal=
axies is extremely nuanced, in large part because we can more easily measur=
e the speeds of far-distant objects that move either away from or toward us=
 in the sky, rather than those that move across the celestial sphere. And a=
s their name implies, dwarf galaxies are extremely small and dim, making th=
eir discoveries even more of a challenge the farther out one looks from the=
 Milky Way. All these effects act to bias the observational data, muddying =
the waters so that a clear trend either of coplanarity or of disorder becom=
es hard to see. The only solution is to find and study dwarf galaxies, near=
 and far, using multiple overlapping and time-consuming methods.</div></div=
><div data-node=3D"node-16" style=3D"box-sizing: border-box; border: 0px; f=
ont-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px=
; outline: 0px; padding: 0px; vertical-align: baseline;" id=3D"yui_3_16_0_y=
m19_1_1518396169439_8198"><div style=3D"box-sizing: border-box; font-size: =
1em; border: 0px; font-style: inherit; outline: 0px; padding-bottom: 18px; =
vertical-align: baseline; line-height: 1.5; word-break: break-word;" id=3D"=
yui_3_16_0_ym19_1_1518396169439_8199">Meanwhile, intriguing observations li=
ke these might do more to actually confirm the success of the LCDM model th=
an to replace it. Michael Boylan-Kolchin, an astrophysicist at The Universi=
ty of Texas at Austin and author of an accompanying commentary in&nbsp;<em =
style=3D"box-sizing: border-box; border: 0px; font-family: inherit; font-we=
ight: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: bas=
eline;" id=3D"yui_3_16_0_ym19_1_1518396169439_8200">Science</em>, says the =
standard model has overcome similar challenges before. =E2=80=9CThe LCDM ha=
s faced many tests and is still the standard cosmological model; I expect t=
he same will be true in the case of satellite planes,=E2=80=9D he says. =E2=
=80=9CHowever, I also think it is essential to fully investigate all potent=
ial inconsistencies. It is the only way we increase our confidence in theor=
ies or, in rare cases, find the flaws that demand fundamental revisions.=E2=
=80=9D</div><div style=3D"box-sizing: border-box; border: 0px; font-family:=
 inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: =
0px; padding: 0px; vertical-align: baseline; position: static;" id=3D"yui_3=
_16_0_ym19_1_1518396169439_8201"></div></div></div></div></div></div><div s=
tyle=3D"box-sizing: border-box; border: 0px; font-family: Roboto, sans-seri=
f; font-size: 16px; margin: auto; outline: 0px; padding: 0px; vertical-alig=
n: baseline; max-width: 1563px; position: relative;" id=3D"yui_3_16_0_ym19_=
1_1518396169439_8202"><div style=3D"box-sizing: border-box; border: 0px; fo=
nt-family: inherit; font-style: inherit; font-weight: inherit; margin: 0px;=
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19_1_1518396169439_8203"><div style=3D"box-sizing: border-box; border: 0px;=
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uto 300px auto auto; outline: 0px; padding: 20px 92px 0px 175px; vertical-a=
lign: baseline; position: relative; width: auto; max-width: 1186px;" id=3D"=
yui_3_16_0_ym19_1_1518396169439_8204"></div></div></div><div style=3D"box-s=
izing: border-box; border: 0px; font-family: Roboto, sans-serif; font-size:=
 16px; margin: auto; outline: 0px; padding: 0px; vertical-align: baseline; =
max-width: 1563px; position: relative;" id=3D"yui_3_16_0_ym19_1_15183961694=
39_8205"><div style=3D"box-sizing: border-box; border: 0px; font-family: in=
herit; font-style: inherit; font-weight: inherit; margin: 0px; outline: 0px=
; padding: 0px; vertical-align: baseline;" id=3D"yui_3_16_0_ym19_1_15183961=
69439_8206"><div style=3D"box-sizing: border-box; border: 0px; font-family:=
 inherit; font-style: inherit; font-weight: inherit; margin: auto 300px aut=
o auto; outline: 0px; padding: 20px 92px 0px 175px; vertical-align: baselin=
e; position: relative; width: auto; max-width: 1186px;" id=3D"yui_3_16_0_ym=
19_1_1518396169439_8207"></div></div></div><div style=3D"box-sizing: border=
-box; border: 0px; font-family: Roboto, sans-serif; font-size: 16px; margin=
: auto; outline: 0px; padding: 0px; vertical-align: baseline; max-width: 15=
63px; position: relative;" id=3D"yui_3_16_0_ym19_1_1518396169439_8208"><div=
 style=3D"box-sizing: border-box; border: 0px; font-family: inherit; font-s=
tyle: inherit; font-weight: inherit; margin: 0px; outline: 0px; padding: 0p=
x; vertical-align: baseline;" id=3D"yui_3_16_0_ym19_1_1518396169439_8209"><=
div style=3D"box-sizing: border-box; border: 0px; font-family: inherit; fon=
t-style: inherit; font-weight: inherit; margin: auto 300px auto auto; outli=
ne: 0px; padding: 20px 92px 0px 175px; vertical-align: baseline; position: =
relative; width: auto; max-width: 1186px;" id=3D"yui_3_16_0_ym19_1_15183961=
69439_8210"><div style=3D"box-sizing: border-box; border: 0px; font-family:=
 inherit; font-style: inherit; font-weight: inherit; margin: 0px; outline: =
0px; padding: 0px; vertical-align: baseline;" id=3D"yui_3_16_0_ym19_1_15183=
96169439_8211"><div data-node=3D"node-18" style=3D"box-sizing: border-box; =
border: 0px; font-family: inherit; font-style: inherit; font-weight: inheri=
t; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;" id=
=3D"yui_3_16_0_ym19_1_1518396169439_8212"><div style=3D"box-sizing: border-=
box; font-size: 1em; border: 0px; font-style: inherit; outline: 0px; paddin=
g-bottom: 18px; vertical-align: baseline; line-height: 1.5; word-break: bre=
ak-word;" dir=3D"ltr" id=3D"yui_3_16_0_ym19_1_1518396169439_8213">As a part=
 of his dissertation work, M=C3=BCller plans to spend time in the upcoming =
months using the Dark Energy Camera in Chile to study the Centaurus A syste=
m with the hopes of finding more dwarf satellites. Another dozen or so in n=
onplanar orbits could make the reported trend disappear. For now though, he=
 is excited about this oddity, because it may actually be the norm. =E2=80=
=9CThese systems aren=E2=80=99t just an outlier =E2=80=94 they look like th=
ey=E2=80=99re more common. I think we have to take this very seriously=E2=
=80=A6. I want us to do further studies of this structure. I want to show t=
hat this isn=E2=80=99t just a coincidence.=E2=80=9D</div></div></div></div>=
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