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There are four popular scenarios...
HOW WILL OUR UNIVERSE END?
WHAT WE STILL DON’T KNOWBig Freeze
The Universe cools and runs out of energy
as it expands. Matter particles drift
aimlessly through space and star
formation ceases, plunging the cosmos
into a frigid darkness.1
HOWTOCOMBINE
GENERAL RELATIVITY
ANDQUANTUMTHEORY
Many of the scenarios describing the end of
the Universe can only be properly assessed
if we can combine the impact of gravity
with the behaviour of very small things
described by quantum theory. At the
moment these are incompatible.
Approaches like string theory and loop
quantumgravityarestillalongwayfrom
being effective, and a whole new theory
may be required before this is possible.2
WHAT DARK MATTER IS
It is impossible to make an
accurate model of the evolving Universe
without knowing what’s in it. There is five
timesasmuchdarkmatterasordinary
matter in the cosmos, yet we don’t even
know if dark matter is a single type of
particle or a whole family, like the Standard
Model of ordinary matter. Many attempts
have been made to detect dark matter, but
all – most recently the LUX collaboration,
one mile under the Black Hills of South
Dakota–havefailed.3
WHAT DARK ENERGY IS
Many researchers are looking into
better ways to model dark energy. For
example, scientists at University College
London and the Centro de Estudios de
Física del Cosmos de Aragón in Spain
recently developed a quicker way to model
theUniversewhichis25timesfasterthan
previous techniques, enabling them to
check many more scenarios. This allows
them to see if hypothetical origins for dark
energy match observations. But we still
haven’tacluewhatitis.Big Rip
With an ever-accelerating expansion,
everything in the Universe (including
fundamental particles) rip themselves apart,
giving off va st amount s of light. In the
extreme, space-time itself disintegrates.Big Crunch
The expansion reverses and the Universe
shrinks down to an infinitely dense point – a
singularity – where all physics as we know it
breaks down, triggering a new Big Bang.Big Bounce
As the shrinking Universe
approaches the singularity,
quantum effects cause the
subatomic particles that
permeate the cosmos to repel
each other. The collapse
reverses and the same
Universe begins to
expand again.Big BangCosmic
expansionUniverse today