NASA’s MAVEN (Mars Atmosphere and Volatile EvolutioN) spacecraft has found “layers” and “rifts” in the electrically charged part of the upper atmosphere (the ionosphere) of Mars.
The phenomenon is known to be very common on Earth and causes unpredictable disruptions to radio communications.
Nevertheless, we do not fully understand the phenomena because they form at altitudes that are very difficult to explore on our planet.
Thankfully we’ve got Mars.
The unexpected discovery by MAVEN shows that Mars is a unique laboratory to explore and better understand this highly disruptive phenomenon. Learning more about it on Mars can help us, in turn, understand the phenomenon here on Earth.
“The layers are so close above all our heads at Earth and can be detected by anyone with a radio, but they are still quite mysterious,” revealed Glyn Collinson of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, lead author of a paper on this research appearing February 3 in Nature Astronomy.
“Who would have thought one of the best ways to understand them is to launch a satellite 300 million miles to Mars?”
Explaining the phenomenon on Mars
Has your favorite radio station has ever been mysteriously jammed or replaced by another station? The likely cause are layers of electrically charged gas, called plasma, located in the very upper-most region of the atmosphere, called the ionosphere.
Appearing suddenly and lasting for many hours, these layers act like giant mirrors in the sky, making radio signals from far away to bounce over the horizon where they interfere with local transmissions, like two people trying to talk over one another.
These layers can also cause interference with radio communications by aircraft and shipping and can blind military radar, which is why understanding the phenomenon is of great importance to scientists.
On our planet, this layer forms up at an altitude just above 100 kilometers. There, the air is too thin for conventional aircraft to be able to fly while being too thick for any satellite to orbit. This means that the only way to reach the height is with a rocket.
However, these missions last dozens of minutes before eventually falling back to Earth. In other words, it’s not an easy area to study.
“We’ve known they exist for over 80 years, but we know so little about what goes on inside them because no satellite can get low enough to reach the layers,” explained Collinson, “at least, no satellite at Earth.”
On Mars, however, things are very different. Spacecraft such as NASA’s MAVEN have the ability to orbit at much lower altitudes and study these features directly.
MAVEV carries a number of scientific instruments that are able to measure plasma in the atmosphere and space surrounding the red planet.
Recent analyses from one of these instruments onboard the spacecraft detected unexpected sudden spikes in the abundance of plasma as it made its way through the Martian ionosphere.
Joe Grebowsky, a former MAVEN project scientist at NASA Goddard, quickly recognized the spike from his earlier experience with rocket flights through the layers at Earth.
It turns out, not only had MAVEN discovered that such layers can occur at other planets than Earth, but the new results reveal that Mars offers what Earth cannot, a place where scientists can reliably explore these layers with satellites, offering first-hand insight on a phenomenon that was previously thought to have been out of reach for current satellites and aircraft on Earth.
“The low altitudes observable by MAVEN will fill in a great gap in our understanding of this region on both Mars and Earth, with really significant discoveries to be had,” revealed Grebowsky, a co-author on the paper.