Skip to main content

Atmosphere Pressure Changes Could Explain Mars Methane

One ongoing mystery on Mars is the sporadic detection of atmospheric methane. Since 1999 detections have been made by Earth-based observatories, orbital missions, and on the surface by the Curiosity Rover. However, other missions and observatories have not detected methane at all, and even when detected, the abundances appear to fluctuate seasonally or even daily.

So, where does this intermittent methane come from? A group of scientists have proposed an interesting theory: the methane is being sucked out of the ground by changes in pressure in the Martian atmosphere. The researchers simulated how methane moves underground on Mars through networks of underground fractures and found that seasonal changes can force the methane onto the surface for a short time.

In their paper, published in the Journal of Geophysical Research: Planets, the scientists say their simulations predict short-lived methane pulses prior to sunrise for Mars’ upcoming northern summer period, which is a candidate time frame for Curiosity’s next atmospheric sampling campaign.

“Our work suggests several key time windows for Curiosity to collect data,” said John Ortiz, a graduate student at Los Alamos National Laboratory who led the research team. “We think these offer the best chance of constraining the timing of methane fluctuations, and (hopefully) down the line bringing us closer to understanding where it comes from on Mars.”

The presence of methane (CH4) in the Martian atmosphere is of great interest to planetary scientists and exobiologists because it could indicate present or past microbial life. Or, it could also be related to nonbiological processes, such as volcanism or hydrothermal activity.

The problem with detecting methane is that it doesn’t last long. Once released into the atmosphere, it can be quickly destroyed by natural atmospheric processes. Therefore, any methane detected in Mars’ atmosphere means it must have been released recently, which only adds to the intrigue.

On Earth, most methane is produced by living creatures such as microorganisms in sedimentary strata, or in the guts of ruminants (cows, sheep, deer, etc.). For methane produced through abiotic or non-living processes, there is a high likelihood it could have been produced millions or even billions of years ago, lying trapped in underground rock formations.

But still, finding methane on Mars is a big deal because of the potential for biological sources, such as methanogenic microbes.

This graphic is the result of an analysis that gives a percentage chance of the methane originating in each grid square centered on Gale Crater. Image Credit: Giuranna et al. (2019)

In 2004, the Mars Express Orbiter (MEO) detected methane in the Martian atmosphere. In 2013 and 2014 Curiosity detected spikes in methane in the atmosphere at Gale Crater. Interestingly, MEO detected a methane spike again, at the same location that Curiosity did, only one day later.

Ortiz and his team wanted to better understand Mars’ methane levels, and used high-performance computing clusters to simulate how methane travels through networks of underground fractures, and then released into the atmosphere when driven by atmospheric pressure fluctuations. They also modeled how methane is adsorbed onto the pores of rocks, which is a temperature-dependent process that may contribute to the methane level fluctuations.

The team said their simulations predicted methane pulses from the ground surface into the atmosphere just before the Martian sunrise in the planet’s northern summer season, which just recently ended. This corroborates previous rover data suggesting that methane levels fluctuated not only seasonally, but also daily. With these insights, the Curiosity rover team can figure out when and where to look for methane, which could aid in the rover’s main goal, searching for signs of life.

“Understanding Mars’ methane variations has been highlighted by NASA’s Curiosity team as the next key step towards figuring out where it comes from,” Ortiz said. “There are several challenges associated with meeting that goal, and a big one is knowing what time of a given sol (Martian day) is best for Curiosity to perform an atmospheric sampling experiment.”

Paper: “Sub-diurnal methane variations on Mars driven by barometric pumping and planetary boundary layer evolution.” Journal of Geophysical Research: Planets. DOI: 10.1029/2023JE008043
LANL press release

The post Atmosphere Pressure Changes Could Explain Mars Methane appeared first on Universe Today.



from Universe Today https://ift.tt/SQ0zp73
via IFTTT
Labels:

Comments

Post a Comment

Popular posts from this blog

Researchers Match Up 12 Meteorites with the Near-Earth Asteroids They Came From

Every day meteoroids blast through our planet’s atmosphere to hit the ground as meteorites. A team of researchers in Italy traced twelve of them to progenitor asteroids that orbit in near-Earth space. Scientists treasure meteorites because they reveal information about their parent bodies. In an arXiv paper, two Italian researchers—Albino Carbognani and Marco Fenucci—analyze the characteristics of the parent bodies of 20 selected meteorites. They were able to track all but eight back to their parent asteroids. Based on their work, the pair says at least a quarter of meteorites come from collisions that happened in near-Earth space and not in the Main Belt. Meteorites from Near-Earth Asteroids: How They Got Here Many meteorites are chondritic, similar to asteroids in the Main Belt (or came from it). In their paper, the authors point out that progenitor meteoroids (including many that fall to Earth and become meteorites) formed millions of years ago following collisions between main-...
Post a Comment
Read more

More Data and Machine Learning has Kicked SETI Into High Gear

For over sixty years, astronomers and astrophysicists have been engaged in the Search for Extraterrestrial Intelligence (SETI). This consists of listening to other star systems for signs of technological activity (or “technosignatures), such as radio transmissions. This first attempt was in 1960, known as Project Ozma, where famed SETI researcher Dr. Frank Drake (father of the Drake Equation) and his colleagues used the Robert C. Byrd Green Bank Telescope in West Virginia to conduct a radio survey of Tau Ceti and Epsilon Eridani. Since then, the vast majority of SETI surveys have similarly looked for narrowband radio signals since they are very good at propagating through interstellar space. However, the biggest challenge has always been how to filter out radio transmissions on Earth – aka. radio frequency interference (RFI). In a recent study, an international team led by the Dunlap Institute for Astronomy and Astrophysics (DIAA) applied a new deep-learning algorithm to data collecte...
Post a Comment
Read more

SETI Researchers Double-Checked 1 Million Objects for Signs of Alien Signals

We can’t help ourselves but wonder about life elsewhere in the Universe. Any hint of a biosignature or even a faint, technosignature-like event wrests our attention away from our tumultuous daily affairs. In 1984, our wistful quest took concrete form as SETI, the Search for Extraterrestrial Intelligence . Unfortunately, or maybe fortunately, SETI has turned up nothing. Recently, scientists used a powerful new data system to re-examine data from one million cosmic objects and still came up empty-handed. Did they learn anything from this attempt? This effort used COSMIC , which stands for  Commensal Open-Source Multimode Interferometer Cluster . It’s a signal-processing and algorithm system attached to the Karl G. Jansky  Very Large Array  (VLA) radio astronomy observatory. According to SETI, it’s designed to “search for signals throughout the Galaxy consistent with our understanding of artificial radio emissions. “ Modern astronomy generates vast volumes of data and al...
Post a Comment
Read more