Swamp Stomp
Volume 16, Issue 46
For up to two billion years in the beginning of Venus’ history, it may have had a shallow liquid-water ocean and habitable surface temperatures, according to computer modeling of the planet’s ancient climate by scientists at NASA’s Goddard Institute for Space Studies (GISS) in New York. NASA scientists used climate models to determine the location of the land and water and that storm clouds could have protected Venus from direct sunlight. These conditions would have made Venus habitable. The model used is very similar to the one used to predict the future climate on Earth. The findings were published in the Geophysical Research Letters journal.
“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,” said Michael Way, a researcher at GISS and the paper’s lead author. “These results show ancient Venus may have been a very different place than it is today.”
There is no way Venus is habitable today. Venus has an overwhelming carbon dioxide atmosphere that is 90 times denser than Earth’s atmosphere. There is almost zero water vapor found on Venus. The surface temperature of Venus is 864 degrees Fahrenheit or 462 degrees Celsius.
Earlier studies have shown that the rate of rotation of a planet impacts whether that planet has a habitable climate or not. One date on Venus equates to 117 days on Earth. It was thought that in order to have a dense atmosphere like on Venus, there needed to be this slow rotation. New research shows that the dense atmosphere could have started as a thin atmosphere like on Earth. That means that years ago Venus may have had a similar rotation rate to Earth.
Another factor to consider is topography. The GISS team theorized that ancient Venus had more dry land overall than Earth, especially in the tropics. This limits the amount of water evaporated and causes the greenhouse effect. “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” (Cabbage and McCarthy).
“In the GISS model’s simulation, Venus’ slow spin exposes its dayside to the sun for almost two months at a time,” co-author and fellow GISS scientist Anthony Del Genio said. “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 research is part of NASA’s Planetary Science Astrobiology program through the Nexus for Exoplanet System Science (NExSS) program, which seeks to accelerate the search for life on planets orbiting other stars, or exoplanets, by combining insights from the fields of astrophysics, planetary science, heliophysics, and Earth science. The findings will affect future NASA missions, including the Transiting Exoplanet Survey Satellite and James Webb Space Telescope, which they are trying to detect possible habitable planets and characterize their atmospheres.
Source: Cabbage, Michael, and Leslie McCarthy. “NASA Climate Modeling Suggests Venus May Have Been Habitable.” Global Climate Change. NASA, 11 Aug. 2016. Web. 01 Nov. 2016.