18 | New Scientist | 28 September 2019Extreme weatherAt last, a new way to
write the number 3JUST weeks after cracking an
elusive problem involving the
number 42, mathematicians
have found a solution to an even
harder problem for the number 3.
Andrew Booker of Bristol
University, UK, and Andrew
Sutherland at the Massachusetts
Institute of Technology have
found a big solution to a problem
known as the sum of three cubes.
It asks whether any wholeRadio waves slow
roach body clocksWEAK radio frequency fields
seem to affect the body clocks
of cockroaches. If the finding is
confirmed, it could mean that
weak radio waves affect other
animals too.
However, Martin Vacha of
Masaryk University in the Czech
Republic, who did the study, is
“very cautious” about the results.
Many claims have been made of
possible effects of electromagnetic
fields on humans and other
animals, in particular that radio
waves from cellphones could
cause cancer. But these are too
weak to cause the DNA damage
that leads to cancer. Nonetheless,
some researchers think the fields
could have more subtle effects.
To test this, Vacha and his
colleagues kept cockroaches in
constant dim UV light, with no
clues as to whether it was night or
day. They measured their activityAnimals^ MathsCLIMATE change will increase the
chance of heavy rainfall and storm
surges combining to cause extreme
flooding around the UK, Germany
and other parts of northern Europe.
Coastal communities already
face the prospect of a worst-case
average sea level rise of about a
metre by the end of the century, as
temperatures rise. But Emanuele
Bevacqua at the University of
Reading, UK, and his colleagues
found the risk from rising seas may
be aggravated further by compound
flooding, where heavy rainfall and
storm surges occur at the same
time to have greater impact.
The team came to this conclusion
after running simulations and
looking at projected changes in
storm surges, precipitation and
waves. The results don’t account for
defences and local topography, butBevacqua says the potential hazard
from compound flooding should still
be factored into risk assessments
for coastal communities.
Today, the Mediterranean coast is
at the greatest risk of such floods in
Europe. If climate change continues
at its current trajectory, however,
the probability of compound
flooding is projected to increase
across more northerly areas.
Those projections are clearest for
the UK west coast, northern France,
the eastern North Sea and parts of
the Black Sea (Science Advances,
doi.org/dbqj). Hotspots in the UK
are expected to include the Bristol
channel and Devon and Cornwall
coasts. However, Bevacqua says it
is hard to pin down precise risk for
very local areas, and this should be
seen more as a broader trend for
northern Europe. Adam VaughanGlobal warming intensifies
risk of bad floods in Europe
number can be represented as
the sum of three cubed numbers.
There were already two known
solutions for the number 3, both
of which involve small numbers:
13 + 1^3 + 1^3 and 4^3 + 4^3 + (-5)^3. But
mathematicians have sought a
third for decades. The solution
found by Booker and Sutherland
is: 569936821221962380720^3 +
(-569936821113563493509)^3 +
(-472715493453327032)^3 = 3.
Earlier this month, the pair
also found a solution to the same
problem for 42, which was the last
remaining unsolved number less
than 100. The duo also found a
solution to the problem for 906.
To find these solutions, Booker
and Sutherland worked with
software firm Charity Engine
to run an algorithm across the
idle computers of half a million
volunteers. For the number 3, the
amount of processing time was
equivalent to a single computer
processor running continuously
for 4 million hours, or more than
456 years. Donna Luto work out what time their body
clocks were keeping.
When they exposed the animals
to either static magnetic fields or
weak radio fields well below the
frequency of cellphone signals,
their periods of activity became an
hour or two longer. In other words,
their body clocks were running
slow (Journal of the Royal Society
Interface, doi.org/dbn9).
Had the cockroaches been
exposed to natural light cycles,
there would probably have been
little impact, says Vacha.
Such results often fail to stand
up to replication, says Peter Hore
at the University of Oxford. One
exception is the disorienting effect
of very weak radio frequency noise
on small migratory songbirds
held in cages, he says.
That is intriguing because the
leading idea for how birds detect
magnetic fields is via proteins
called cryptochromes – and
cryptochromes also play a key role
in maintaining circadian rhythms
in animals. Michael Le PageCH
RIS
TO
PH
ER
FU
RL
ON
G/G
ET
TY
ANGIEPHOT
OS/GETTYNews In brief