After NASA discovered “water sufficient for abundant life,” Venus was chosen as the target of two new NASA missions to study the planet’s atmosphere and geological features.
The space agency has announced that he will send two robotic missions to Earth by the end of the decade. NASA Administrator Bill Nelson said the da Vinci+ and Veritas probes “provide an opportunity to study a planet we haven’t been to in over 30 years.” Selected according to a peer-review process, missions to planets closest to Earth explore how a once habitable world became a “hot, hellish, unforgiving” planet.
This comes just months after a British astronomer discovered phosphine gas 30 miles above him in Venus’ clouds, leading researchers to believe it was a sign of extraterrestrial life. . Scientists at NASA’s Goddard Space Institute (GISS) also previously discovered that Venus may have once had shallow liquid water oceans and habitable surface temperatures for two billion years. was
The results, published in the journal Geophysical Research Letters, were obtained using models similar to the types used to predict future climate change on Earth.
Michael Way, a researcher at GISS and the paper’s lead author, said: “Many of the same tools we use to model climate change on Earth can be adapted to study climates on other planets, both past and present.
“These results show ancient Venus may have been a very different place than it is today.”
Scientists have long theorized that Venus was formed out of ingredients similar to Earth’s, but followed a different evolutionary path.
Measurements by NASA’s Pioneer mission to Venus in the Eighties first suggested Venus originally may have had an ocean, but its proximity to the Sun means it receives far more sunlight than Earth.
This led scientists to believe that the planet’s early ocean evaporated, water-vapour molecules were broken apart by ultraviolet radiation, and hydrogen escaped to space.
With no water left on the surface, carbon dioxide built up in the atmosphere, causing a runaway greenhouse effect that created present conditions.
The GIIS team also suggested the 2016 data showed ancient Venus had more dry land overall than Earth, especially in the tropics.
A NASA press release added: “This type of surface appears ideal for making a planet habitable, there seems to have been enough water to support abundant life, with sufficient land to reduce the planet’s sensitivity to changes from incoming sunlight.”
Researchers simulated conditions of a hypothetical early Venus with an atmosphere similar to Earth’s, a day as long as Venus’ current day, and a shallow ocean consistent with early data from the Pioneer spacecraft.
Co-author Anthony Del Genio said: “In the GISS model’s simulation, Venus’ slow spin exposes its dayside to the Sun for almost two months at a time.
“This warms the surface and produces rain that creates a thick layer of clouds, which acts like an umbrella to shield the surface from much of the solar heating.
“The result is mean climate temperatures that are actually a few degrees cooler than Earth’s today.”
The last US probe to visit Venus was the Magellan orbiter in 1990.
However, other spacecraft – from Europe and Japan – have orbited the planet since then.
The Davinci+ (Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging) mission will measure the planet’s atmosphere to gain insight into how it formed and evolved.
It will also aim to determine whether Venus ever had an ocean.
DAVINCI+ may also shed some light on observations of phosphine gas in Venus’s atmosphere.
If the spacecraft finds compelling evidence of the chemical phosphine, it may be a sign of life in the Venusian clouds.
The other mission, Veritas (Venus Emissivity, Radio Science, InSAR, Topography, and Spectroscopy), will map the planet’s surface to understand its geological history and investigate how it developed so differently than Earth.
It will use a form of radar to chart surface elevations and discover whether volcanoes and earthquakes are active.
Updated version of the previous article.