After NASA found "enough water to support plentiful life," the planet Venus was selected as the target of two new NASA missions to study the planet's atmosphere and geological features.
By the end of the decade, the space agency plans to deploy
two robotic missions to the planet. The probes, Davinci+ and Veritas, will
provide a "chance to investigate a planet we haven't been to in more than
30 years," according to NASA administrator Bill Nelson. After a
peer-review procedure, the missions to Earth's closest planetary neighbour were
selected. They will investigate how the once-habitable planet became into a
"hot, hellish, unforgiving" planet.
It happened only a few months after UK astronomers made
headlines when they found phosphine gas 30 miles above Venus' clouds.
Scientists speculated that the discovery might be evidence of extraterrestrial
life.
Prior research conducted by scientists at NASA's Goddard
Institute for Space Studies (GISS) suggested that Venus may have once had a
shallow ocean of liquid water and a temperature that was suitable for life for
up to two billion years.
The results were achieved using a model akin to that which
is used to forecast future climate change on Earth, and they were published in
the journal Geophysical Research Letters.
"MANY OF THE SAME TOOLS WE USE TO MODEL CLIMATE CHANGE ON EARTH CAN ADAPTED TO STUDY CLIMATES ON OTHER PLANETS, BOTH PAST AND PRESENT," stated Michael Way, a researcher at GISS and the lead author of the paper.
"IT APPEARS THAT ANCIENT VENUS MAY HAVE BEEN A VERY
DIFFERENT PLACE THAN IT IS TODAY," the results indicate.
For a very long time, scientists have postulated that Venus
evolved differently from Earth, using components that are comparable to
Earth's.
Venus may have formerly had an ocean, according to
measurements made by NASA's Pioneer mission to the planet in the 1980s.
However, because Venus is so close to the Sun, it gets significantly more
sunlight than Earth.
As a result, scientists came to the conclusion that hydrogen
fled to space, the planet's primordial ocean evaporated, and ultraviolet light
split apart molecules of water vapour.
The current conditions were brought about by a runaway
greenhouse effect caused by carbon dioxide building up in the atmosphere when
there was no longer any water on the surface.
The GIIS team also proposed that evidence from 2016
indicated that, generally speaking, ancient Venus had more dry land than Earth,
particularly in the tropics.
This type of surface appears ideal for making a planet
habitable; there appears to have been enough water to support abundant life,
with enough land to lessen the planet's sensitivity to changes from incoming
solar light, according to a NASA press release.
Researchers created a virtual early Venus that had a shallow
ocean that was compatible with early data from the Pioneer spacecraft, an
atmosphere like Earth's, and a day that was as long as Venus's present day.
CO-AUTHOR ANTHONY DEL GENIO SAID: "VENUS' SLOW SPIN EXPOSES ITS DAYSIDE TO THE SUN FOR ALMOST TWO MONTHS AT A TIME IN THE GISS MODEL'S SIMULATION."
In addition to warming the surface, this causes rain to form
a thick layer of clouds that shields the surface from much of the sun's heat,
acting as an umbrella.
"THE END RESULTS IN MEAN CLIMATE TEMPERATURES THAT ARE
ACTUALLY COOLER THAN CURRENT EARTH TEMPERATURES."
The Magellan orbiter was the final American spacecraft to
visit Venus in 1990.
Since then, though, several spacecraft have orbited the
planet, including ones from Europe and Japan.
In order to learn more about the formation and evolution of
the planet's atmosphere, measurements of it will be made by the Davinci+ (Deep
Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging) mission.
It will also try to find out if there was once an ocean on
Venus.
Moreover, DAVINCI+ might provide some clarification on
reports of phosphine gas detected in Venus's atmosphere.
It could indicate the presence of life in the Venusian
clouds if the spacecraft discovers strong evidence of the chemical phosphine.
Venus Emissivity, Radio Science, InSAR, Topography, and
Spectroscopy (Veritas) is the other project that will scan the planet's surface
in order to learn more about its geological past and explore why it developed
so differently from Earth.
It will map surface elevations and determine whether volcanoes and earthquakes are active using a type of radar.
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