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PLANETARY SCIENCEToxic
Transformation
How Venus might have changed
from habitable to harshBelow Venus’s toxic clouds of sulfuric acid
is an apocalyptic world, with temperatures
hot enough to melt lead and pressures that
could crush heavy machinery. But it might
not always have been so.
In 2016 Michael Way of nasa’s Goddard
Institute for Space Studies and his colleagues
applied the first three-dimensional climate
model to early Venus. They found it could
once have been so temperate that liquid water
pooled in vast oceans—the key to life as we
know it. Now Way and Anthony Del Genio,
also at Goddard, have developed a framework
for the planet’s evolution based on more com-
plex data that incorporates various topographies
and different amounts of sunlight. Their study,
published in May in the Journal of Geophysical
Research: Planets, puts forward a new explana-
tion for how Venus could have remained habit-
able for nearly three billion years before morph-
ing into today’s blistering hellscape.
Many scientists have postulated that Venus
was bone-dry from the beginning and never
hosted liquid water. Roughly 4.5 billion years
ago, when the solar system formed, the second
planet from the sun would have received
enough sunlight that any atmospheric water
was lost to space—and the radiation would
have thwarted the formation of life as it exists
on Earth. “There would have been nothing,”
Way says, without some mitigating factor.
That factor, he and Del Genio argue, could have
been a supersized cloud that developed early
ALAMYin the planet’s evolution and cooled the world.© 2020 Scientific American © 2020 Scientific American