SPACE
Physicists simulate the
origins of the universe
WordsbyTimChildersT
heformationofgalaxies is a complex
dancebetweenmatter and energy,
occurringona stage of cosmic
proportionsandspanning billions of years.
Howthediversityofstructured and dynamic
galaxiesweobservetoday arose from the
fierychaosoftheBigBang remains one of the
mostdifficultunsolvedpuzzles of cosmology.
Insearchofanswers,an international
teamofscientistshascreated the most
detailedlarge-scalemodel of the universe to
date,a simulationtheycall TNG50. Their
virtualuniverse,some230 million light years
wide,containstensofthousands of evolving
galaxieswithlevelsofdetail previously seen
onlyinsingle-galaxymodels. The simulation
trackedmorethan 20 billion particles
representingdarkmatter, gases, stars and
supermassiveblackholes over a 13.8-billion-
yearperiod.
Theunprecedentedresolution and scale
allowedtheresearchersto gather key insightsinto our own universe’s past, revealing how
various oddly shaped galaxies morphed
themselves into being and how stellar
explosions and black holes triggered this
galactic evolution.
TNG50 is the latest simulation created by
the IllustrisTNG project, which aims to build
a complete picture of how our universe
evolved since the Big Bang by producing a
large-scale universe without sacrificing the
fine details of individual galaxies.
TNG50 has allowed researchers to see
firsthand how galaxies may have emerged
from the turbulent clouds of gas present
shortly after the universe was born. They
discovered that the disc-shaped galaxies
common to our cosmic neighbourhood
naturally emerged within their simulation
and produced internal structures including
spiral arms, bulges and bars extending from
their central supermassive black holes. When
they compared their computer-generateduniverse to real-life observations, they found
their population of galaxies was qualitatively
consistent with reality.
As their galaxies continued to flatten into
well-ordered rotating discs, another
phenomenon began to emerge. Supernovae
explosions and supermassive black holes at
the heart of each galaxy created high-speed
outflows of gas. These outflows morphed into
fountains of gas rising thousands of light
years above a galaxy. The tug of gravity
eventually brought much of this gas back into
the galaxy’s disc, redistributing it to its outer
edge and creating a feedback loop of gas
outflow and inflow. Apart from recycling the
ingredients for forming new stars, the
outflows were also shown to change their
galaxy’s structure. The recycled gases
accelerated the transformation of galaxies
into thin rotating discs – despite these initial
findings, however, the team is far from
finished dissecting their model.“Galaxies we
observe todayarose from the
fiery chaos of theBig Bang"
016 HowIt Works http://www.howitworksdaily.com
IN ASSOCIATION WITHThe centres of massive
galaxy clusters are super
hot (red), while bright
structures show diffuse
gas from the intergalactic
medium shock heating at
the boundary between
© TNG Collaborationcosmic voids and filaments