14 | New Scientist | 4 July 2020PhysicsTHE largest lightning flash ever
measured has been identified. More
than twice the size of the previous
record, it spanned 709 kilometres –
about the distance from London to
Geneva. A second flash has become
the world’s longest. It went on for
16.7 seconds, also doubling the
previous record.
Until recently, lightning was
primarily tracked using ground-
based sensors. In 2017, the UN’s
World Meteorological Organization
(WMO) used these to certify two
world records: a lightning flash over
Oklahoma in 2007 that spanned
321 kilometres and a 2012 flash
over France lasting for 7.74 seconds.
However, in 2016, the US
launched the world’s first lightning-
mapping satellite. This gives much
more comprehensive coverage
of Earth’s surface. Two flashes
detected from space have now been
certified by the WMO as covering
the longest distance and having
the longest duration respectively.
The 709-kilometre flash
happened on 31 October 2018
over southern Brazil and part of
north-east Argentina. The satellite
image revealed dozens of branches
from the core flash.
On 4 March 2019, the
16.7-second flash occurred over
northern Argentina. Both were
cloud-to-cloud flashes and so didn’t
hit the ground (Geophysical Research
Letters, doi.org/d2hn).
The flashes were so huge
because of the powerful “mesoscale
convective systems” that develop
over the plains of South America,
says Randall Cerveny at Arizona
State University. “They’re aggregate
individual superstorms that merge
together into massive storms.”
Similar huge storms form
over North America’s Great Plains.
Within the storm clouds, enormous
electrical charges can build up,
ultimately discharging over huge
distances through the air. ❚Michael MarshallNews
We have recorded
the biggest ever
lightning flashPsychologyJessica HamzelouHAVING a baby means
new responsibilities, and
parenthood should make
people more mature – or so the
theory goes. In fact, parents’
personalities seem more likely
to change in other ways. A study
now hints that new mothers
become more agreeable and
extroverted, and new fathers
become a little less extroverted,
but more conscientious.
Eva Asselmann and Jule
Specht at Humboldt University
of Berlin studied socio-
economic data collected from
19,875 people in Germany
who have undergone yearly
assessments since 1984. The
volunteers took personality
tests four times between 2002
and 2017 – during which 6891
of them became parents.
The assessments were
designed to measure aspects
of the “Big Five” model of
personality, which captures
a person’s openness,conscientiousness,
extroversion, agreeableness
and emotional stability.
A number of studies have
shown that people in their 20s
and 30s tend to become more
agreeable, more emotionally
stable and more conscientious.
But it isn’t clear why, says
Manon van Scheppingen
at Tilburg University in
the Netherlands.
“It could be that it’s genetics –
that it’s something that happens
when the brain matures,” she
says. “But we know that the
environment plays a role.” Some
have theorised that the change
might be triggered by becominga parent, which often happens
around this age.
“One might assume that the
birth of a child relates to an
increase in conscientiousness,
agreeableness or emotional
stability – but we did not find
this,” says Asselmann.
Instead, it turned out that, in
the year before the birth of their
first child, would-be parents
were more likely to be less open
and more extroverted than non-
parents. This suggests that they
are less willing to try new and
potentially risky experiences,
but are social and assertive.
Both of these traits can
change once a baby is born.
People become even less open
when they become parents,
and this effect seems to last for
at least three years. And while
extroversion increases slightly
on average after the birth, it
declines in the following years.
Parenthood appears to affect
men and women in different
ways. While women generally
seem to become more agreeable
in the three years followingthe arrival of a child, men seem
to become more conscientious,
suggesting they develop more
self-control.
This might be a result of
people falling into traditional
stereotypes, with women
spending more time with the
baby and men feeling more
pressure to provide financial
support, say Asselmann and
Specht (European Journal of
Personality, doi.org/d2g9).
But neither gender showed
an increase in emotional
stability, which is thought to
be a key indicator of maturity.
The findings chime with other
research, which suggests that
new mothers experience a
decline in conscientiousness
or self-control after the birth
of a child, says van Scheppingen.
New parents needn’t worry,
says van Scheppingen, their
altered personalities aren’t
set in stone. Plenty of research
shows that personality changes
over the course of a person’s
life. And the changes that
occur with parenthood might
not last beyond a few years.
“The changes are small,” she
says. “It’s not as if you become
a completely different person.” ❚New parents get a
personality transplant
GETT
Y^ IMAGES
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INTIMAG
ES
RFA baby changes
your life – and
your personality“ New mothers may
become more agreeable
while new fathers tend to
become less extroverted”