The thick atmosphere of Venus contains over a million times as much sulphur dioxide as Earth’s, where almost all of the pungent, toxic gas is generated by volcanic activity.
Is Venus volcanically active?
Most of the sulphur dioxide on Venus is hidden below the planet’s dense upper cloud deck, because the gas is readily destroyed by sunlight.
That means any sulphur dioxide detected in Venus’ upper atmosphere above the cloud deck must have been recently supplied from below.
Venus is covered in hundreds of volcanoes, but whether they remain active today is much debated, providing an important scientific goal for Venus Express.
The mission has already found clues pointing to volcanism on geologically recent timescales, within the last few hundreds of thousands to millions of years.
A previous analysis of infrared radiation from the surface pointed to lava flows atop a volcano with a composition distinct from those of their surroundings, suggesting that the volcano had erupted in the planet’s recent past.
Now, an analysis of sulphur dioxide concentration in the upper atmosphere over six years provides another clue.
Immediately after arriving at Venus in 2006, the spacecraft recorded a significant increase in the average density of sulphur dioxide in the upper atmosphere, followed by a sharp decrease to values roughly ten times lower by today.
A similar fall was also seen during NASA’s Pioneer Venus mission, which orbited the planet from 1978 to 1992.
At that time, the preferred explanation was an earlier injection of sulphur dioxide from one or more volcanoes, with Pioneer Venus arriving in time for the decline.
“If you see a sulphur dioxide increase in the upper atmosphere, you know that something has brought it up recently, because individual molecules are destroyed there by sunlight after just a couple of days,” says Dr Emmanuel Marcq of Laboratoire Atmosphères, Milieux, Observations Spatiales, France, and lead author of the paper published in Nature Geoscience.
“A volcanic eruption could act like a piston to blast sulphur dioxide up to these levels, but peculiarities in the circulation of the planet that we don’t yet fully understand could also mix the gas to reproduce the same result,” adds co-author Dr Jean-Loup Bertaux, Principal Investigator for the instrument on Venus Express that made the detections.
Venus has a ‘super-rotating’ atmosphere that whips around the planet in just four Earth-days, much faster than the 243 days the planet takes to complete one rotation about its axis.
Such rapid atmospheric circulation spreads the sulphur dioxide around, making it difficult to isolate any individual points of origin for the gas.
Dr Marcq’s team speculate that if volcanism was responsible for the initial increase, then it could come from a relatively gentle increased output of several active volcanoes rather than one dramatic eruption.
“Alternatively, and taking into account the similar trend observed by Pioneer Venus, it’s possible that we are seeing decadal-scale variability in the circulation of the atmosphere, which is turning out to be even more complex than we could ever have imagined,” he notes.
“By following clues left by trace gases in the atmosphere, we are uncovering the way Venus works, which could point us to the smoking gun of active volcanism,” adds Håkan Svedhem, ESA’s Project Scientist for Venus Express.
Predicting unpredictability: Information theory offers new way to read ice cores
07.12.2016 | Santa Fe Institute
Sea ice hit record lows in November
07.12.2016 | University of Colorado at Boulder
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
08.12.2016 | Life Sciences
08.12.2016 | Physics and Astronomy
08.12.2016 | Materials Sciences