York is a trusted partner on NASA missions. In fact, one of the University’s Organized Research Units, the Centre for Research in Earth and Space Science (CRESS), is at the forefront of planetary exploration and space technology.
With funding from the Canadian Space Agency, Professor John Moores (Lassonde School of Engineering, CRESS member and York Research Chair in Space Exploration) recently advanced the goal of understanding and measuring methane on the famous red planet, Mars.
The resulting white paper, “High-frequency near-surface gas measurement: an opportunity to solve puzzles in planetary atmospheric processes in Martian methane and beyond,” was the first of two papers submitted into the Planetary Decadal Survey (2020). The white papers will be published in the Bulletin of the American Astronomical Society. Ultimately, this research could help to shape NASA’s future ventures over the next 10 years.
A member of the Royal Society of Canada, Moores is an internationally recognized planetary scientist and space engineer. The white paper’s co-authors included Moores’ Research Associate Haley Sapers, as well as researchers from McGill University, the Planetary Science Institute and Aeolis Research. Co-signatories included scholars from Princeton University and the Universities of Winnipeg, Michigan, Colorado, Arizona and Florida.
Moores sits down with Brainstorm to discuss the paper’s significance and York University as a leader in this realm.
Q: How influential is the Planetary Decadal Survey?
A: It brings together scientists from around the world who study planets and participate in robotic space exploration to put their best ideas into a single plan for what missions we hope to launch over the next decade.
A panel of senior scientists will read all the white papers and deliberate about how we should proceed. Major space agencies, notably NASA, look to the final document to guide their activities.
There was a robust response this year: 574 papers were submitted. There were others from York. Professor Isaac Smith, Canada Research Chair in Planetary Science, contributed as well.
Q: Why was the discovery of methane on Mars a surprise and a significant discovery?
A: It’s an unexpected gas, a gas that shouldn’t last in the Martian atmosphere. Our current understanding of this atmosphere suggests that methane should disappear within about 300 years. This may sound like a long time, but over the history of the planet, it’s short.
This tells us that methane is being produced fairly recently.
What gets people really excited about methane is that the processes that create it tend to involve things like microbes [microscopic living organisms, such as bacteria, protozoa, fungi, algae and amoebas] in the subsurface or reactions with hot water. It’s a window into very interesting processes about how Mars might be working today.
Q: You found that methane amounts change with the seasons. Please elaborate.
A: It isn’t the case that Mars’ atmosphere heats up in the spring that’s significant, since that can’t change how much methane there is. The fact that the ground gets warmer starting in the spring might have something to do with these processes locally at Gale crater. But it’s the constant and consistent change, year to year, that tells us that something interesting is happening. You also get periodic spikes in the methane concentration that seem to go away much more rapidly than 300 years, which is also very surprising.
What it’s telling us is that there’s some process on the planet that’s emitting methane every single year, and at the same times of the year and, in turn, there’s some process that destroys it every year at the same time.
There’s a sort of breathing of the soil. It’s of interest to those people who think about water and life on Mars.
Q: What kind of temperature changes are we talking about?
A: The average temperature on Mars is -60C. You might get to +30C on the hottest day of the year. At night, it can get extremely cold. It typically cools off by 80 to 100C because the atmosphere’s so thin. You can easily get down below -100C at night.
Q: From where, exactly, does the methane come?
A: The surface of Mars measures higher amounts of methane – more specifically, Curiosity measures higher amounts of methane near the surface of the planet. Now, there are spacecraft, the Trace Gas Orbiter to be precise, that look at the upper atmosphere from orbit and they don’t see any methane. So, the only way that these two realities make sense is if the methane accumulates at night near the surface. (For convenience, the spacecraft, Curiosity Rover, makes all its measurements in the middle of the night. That’s why it was able to see the variance.)
Then, in the day when weather sets in – clouds, etc. – the gas is diluted into the atmosphere. It’s the mixing that takes place when the sun rises and starts to heat the surface that dilutes the methane. While we do sometimes see this as clouds, particularly late afternoon thunderstorms, most people would have experience with this effect as turbulence with warm air rising and cool air descending.
By being able to see how methane rises and falls over the course of the day and over the course of the year, we could tell how much is being generated.
Q: What else can the fluctuations of methane on Mars tell us?
A: In order to see the methane at some times but not at other times, there needs to be some process that we’re missing, something that we don’t understand about how Mars works.
I expect it’s something to do with the surface. We know that there are strong oxidants in the Martian soil. You could have those reacting with the small amount of methane in the atmosphere, and perhaps getting rid of the methane fairly quickly.
Others have suggested there are electrical reactions that happen in the Martian atmosphere that destroy the methane. But no one has any solid evidence. This is a missing piece of the puzzle. More measurements, and more measurements throughout the day, would really help us.
Q: How could this hint at life on Mars?
A: Knowing more about this would provide good data that could help us to create a model of these things. If we were really lucky, we might even be able to look at the different versions of methane – some are associated with biological processes, some are associated with geological processes. It would help to determine if the methane on Mars comes from life or from some other process.
There’s something about Mars that we don’t understand; there’s discovery to be made.
Q: You share the use of the Curiosity Rover to study methane on Mars. What are the challenges in doing this?
A: Curiosity landed on Mars in 2012 and it has been in continuous use since. There are 460 scientists on the team, all undertaking different investigations.
Measuring methane takes a great deal of time and effort for the spacecraft. We generally get a couple of observations every year. There’s a team deciding what the robot does every day. My grad students decide on the atmospheric investigations that take place. They really enjoy this.
In my group, we make movies of the clouds on Mars, every couple of weeks, and from these, we can say something about the weather. It’s like six minutes of looking through the equivalent of a toilet paper roll into the sky.
Q: What are the biggest challenges in studying the Martian atmosphere?
A: There haven’t been very many measurements. They’re hard to make and there are very few of them – just little snapshots. Over the past eight years, we’ve looked for methane 14 times. When you put all these glimpses together, you start to see the cycle.
Q: How does York University fare in space exploration?
A: This University is a leader. CRESS has been around since 1965 and York has led several space instruments for NASA missions. Most recently, we had a great success with the OSIRIS-Rex Laser Altimeter. This is Professor Mike Daly’s work. The OSIRIS-Rex spacecraft just landed on the asteroid Bennu to collect material from the surface that could tell us about the origins of Earth.
I don’t think you have this level of history, this level of experience, anywhere else in Canada.
To read the white paper, link here. The second paper, led by Sapers, is available here. It describes the sort of mission that could investigate the science in the first white paper. For more on NASA and the Curiosity Rover, visit the website.
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By Megan Mueller, senior manager, Research Communications, Office of the Vice-President Research & Innovation, York University, email@example.com