Astronomers use slime mould to map the universe’s largest structures

1.

ASTRONOMERS USE SLIME MOULD TO MAP
THE UNIVERSE’S LARGEST STRUCTURES
NAUMUSHKIN ILYA
2ND YEAR
AM – 28
TEACHER:
A.V. YURIEVA

2.

THE BEHAVIOUR OF ONE OF NATURE’S HUMBLEST CREATURES AND ARCHIVAL
DATA FROM THE NASA/ESA HUBBLE SPACE TELESCOPE ARE HELPING
ASTRONOMERS PROBE THE LARGEST STRUCTURES IN THE UNIVERSE
The single-cell organism known as slime mould builds
complex web-like filamentary networks in search of
food, always finding near-optimal pathways to connect
different locations.
The cosmic web is the large-scale backbone of the
cosmos, consisting primarily of dark matter and laced
with gas, upon which galaxies are built.
The Cosmic Web (Artist’s Impression)

3.

The existence of a web-like structure to the
Universe was first hinted at in galaxy
surveys in the 1980s.
Now a team of researchers has turned to
slime mould to help them build a map of
the filaments in the local Universe (within
100 million light-years of Earth) and find the
gas within them.
Slime mould
They designed a computer algorithm,
inspired by the behaviour of slime mould,
and tested it against a computer simulation
of the growth of dark matter filaments in
the Universe.
The Cosmic Web

4.

The researchers then applied the slime mould
algorithm to data containing the locations of over
37000 galaxies mapped by the Sloan Digital Sky
Survey. The algorithm produced a three-dimensional
map of the underlying cosmic web structure.
They then analysed the light from 350 faraway
quasars catalogued in the Hubble Spectroscopic
Legacy Archive. Imprinted on that light was the
telltale signature of otherwise invisible hydrogen gas
that the team analysed at specific points along the
filaments. These target locations are far from the
galaxies, which allowed the research team to link the
gas to the Universe’s large-scale structure.

5.

“It’s really fantastic that one of the simplest forms of
life actually enables insights into the very largest-scale
structures in the Universe,” said lead researcher
Joseph Burchett of the University of California (UC),
U.S.A.
“By using the slime mould simulation to find the
location of the cosmic web filaments, including those
far from galaxies, we could then use the Hubble Space
Telescope’s archival data to detect and determine the
density of the cool gas on the very outskirts of those
invisible filaments. Scientists have detected signatures
of this gas for over half a century, and we have now
proven the theoretical expectation that this gas
comprises the cosmic web.”
UC Santa Cruz

6.

The survey further validates research that indicates intergalactic gas is organized into filaments and also reveals how
far away gas is detected from the galaxies. Team members were surprised to find gas associated with the cosmic web
filaments more than 10 million light-years away from the galaxies.
But that wasn’t the only surprise. They also discovered that the ultraviolet signature of the gas gets stronger in the
filaments’ denser regions, but then disappears. “We think this discovery is telling us about the violent interactions
that galaxies have in dense pockets of the intergalactic medium, where the gas becomes too hot to detect,” Burchett
said.

7.

The researchers turned to slime mould simulations
when they were searching for a way to visualise
the theorised connection between the cosmic web
structure and the cool gas, detected in previous
Hubble spectroscopic studies.
The research team was inspired by how the slime
mould builds complex filaments to capture new
food, and how this mapping could be applied to
how gravity shapes the Universe, as the cosmic
web constructs the strands between galaxies and
galaxy clusters.
MAP OF THE COSMIC WEB GENERATED FROM SLIME MOULD
ALGORITHM