14 | New Scientist | 19 October 2019
AT FIRST glance, the velvety grey
that trims the gnarled branches
of this Monterey cypress tree might
look like snow. But this otherworldly
scene is the result of algae and
lichen growth and occurs at only
one place in the world: a protected
coastal zone in the Point Lobos
State Natural Reserve in California.
The image, taken by Zorica
Kovacevic, is a 2019 Wildlife
Photographer of the Year winner,
announced this week. Run by the
Natural History Museum in London,
the competition showcases the
world’s best nature photography.
The spongy orange growths
on the branches are a green
alga that has been coloured by
carotenoid pigments. Although
abundant in nature, it is found
on Monterey cypresses only at
Point Lobos, where clean air and
moisture create ideal conditions
for growth. The snow-like deposits
are a lace lichen. ❚BotanyFANCY a trip down a wormhole?
Calculations suggest that this
might be possible, because these
portals through space-time could
stick around forever.
Wormholes are essentially
a pair of connected black holes.
Two types could theoretically
exist. A non-traversable wormhole
is like a room with two doors
that can be used only from the
outside – the doors are black
holes through which things can
enter, but never escape. “These
are not very interesting, as any
astronaut who is brave enough
to venture in won’t be able to
make it back to tell the story,” says
Diandian Wang at the University
of California, Santa Barbara.Traversable wormholes are also
possible, but until now we didn’t
know whether they could exist
for long enough for anything to
pass through them.
For such a wormhole to
form, space-time needs to
spontaneously change shape.
In classical physics, this can’t
happen. But the rules of quantum
mechanics allow space-time to
do so for brief periods.
Wang worked on a scenario
involving string theory, in which
the fundamental ingredient of
reality is tiny strings. If one of
these strings breaks, it can create
a traversable wormhole with black
hole-like portals either end that
allow both entry and exit.Although researchers had
shown that this was a possibility
before, it seemed that the energy
involved would always snap
the wormhole.
Now, Wang and his team have
calculated that the curvature of
space-time could counteract thisacceleration, keeping the pseudo
black holes static and allowing
the throat of the wormhole to
remain open (Classical and
Quantum Gravity, doi.org/dchc).
This scenario is extremelyunlikely, and becomes even
more unlikely the longer the
wormhole is and the larger
the black holes are. Thanks to
quantum mechanics, though,
the probability of it happening
isn’t zero.
Wang’s team also calculated
that, once a traversable wormhole
exists, it could remain stable for
at least as long as the universe
has been around.
The work shows how
wormholes could be created
from scratch, says Aron Wall
at the University of Cambridge.
But he points out that they
couldn’t be used to time travel
or move faster than light. ❚CosmologyWormholes could last as long as the universe
Donna LuTrees from a fantasy scene
California’s weird trees are captured in an award-winning image
ZORICA KOVACEVIC/WILDLIFE PHOTOGRAPHER OF THE YEARNews
“ Any astronaut brave
enough to venture in
won’t be able to make
it back to tell the story”Chelsea Whyte