Martian Mystery

SCIENCE

Teachers, scroll down for a quick list of key resources in our Teachers’ Toolkit.

Discussion Ideas

Read through the Nat Geo News article. What group of people discovered the mysterious Martian clouds in 2012?
- Citizen scientists! Amateur astronomers from the international Association of Lunar and Planetary Observers made the preliminary discovery in 2012. Just like professional scientists, these top-notch citizen scientists relied on each other to duplicate findings—one observer in Pennsylvania first verified his observances with colleagues in Australia, then France. Well-done. Follow your own passion with citizen science and you might make a discovery yourself!

Read through our activity “Design a Space Probe.” There are two major types of space probes: orbiters and landers/rovers. What is the difference?
- Orbiters make observations and collect data from orbit, high above the planet itself. The Mars Atmosphere and Volatile Evolution Mission (MAVEN), mentioned in the Nat Geo News article, is an orbiter currently orbiting the Red Planet.
- Landers and rovers, as their names imply, explore the surface of the planet itself. Landers are stationary. Rovers are motor vehicles that can be remote-controlled by engineers back on Earth. Mars has hosted several rovers, including Sojourner, Spirit and Opportunity, and Curiosity. Opportunity and Curiosity are still active!

Could an orbiter or a rover observe the mysterious Martian clouds? Which one would you send to collect data on the phenomenon?
- Both orbiters and rovers are capable of observing a planet’s atmosphere. They just do it from different perspectives.
  - Orbiters could observe clouds (and the Martian surface) from above—satellite imagery.
  - Landers and rovers would have to “look up” to observe atmospheric clouds from ground-level. The lovely Martian sunset at the top of this image, for instance, was taken with the Spirit rover.

Wait a minute. So, we already have orbiters and rovers on Mars, and they’re both very capable of observing the atmosphere. Why haven’t they spotted the mysterious clouds?
- The clouds are only present in isolated places during short periods of time. Scientists would have to be very, very lucky to stumble into an atmospheric phenomenon that cannot be predicted.

How are the mysterious clouds so different from the hazy, everyday Martian clouds astronomers are used to seeing?
- The mystery clouds are found much, much higher in the Martian atmosphere. “All of those other clouds, which have been made of dust or ice particles, have never risen more than 60 miles (100 kilometers) above the surface. The mystery clouds, however, reached more than twice as high,” according to Nat Geo News.

What are the two leading theories about what the clouds are?
- One theory is that the clouds were created in the same way as the lower-altitude dust and ice clouds.
- The other major theory is that the clouds are actually very bright auroras.

Why do astronomers say the high-altitude cloud theory is “difficult to support”?
- “It’s hard to see how particles would get up that high,” says one astronomer quoted by Nat Geo News. And even if they did, he says, “there are winds at these altitudes, and I would expect that they would redistribute or dissipate a cloud relatively quickly.”

Why do astronomers say the aurora theory is problematic?
- Those auroras, created by the solar wind interacting with the Martian atmosphere, would have to be incredibly bright to be seen all the way from Earth.

How are astronomers hoping to figure out this mystery?
- “We just have to keep watching with telescopes on Earth and with spacecraft,” says another astronomer. “And because they’re so numerous, so widely spread around Earth, and so dedicated,” he says, “amateurs will continue to play a fundamental role.”
- Citizen scientists, keep your eyes on the skies!