Mars has long held our fascination. As the second-closest planet to Earth and one whose solid surface can be observed through a telescope at night sky locations around it, this fascinating world remains of interest to humanity.
Over time, scientists have amassed an enormous amount of information on Mars. Here are some of the most fascinating finds they have made during close examination of this mysterious world.
Dust Devils
Dust devils (also called dust whirlwinds) are short-lived phenomena that may appear at certain times of year on Earth. Usually found in desert regions with high surface temperatures and low air pressure, where strong updrafts create tornado-like winds with great speed – typically reaching heights between two feet to hundreds of metres tall.
Dust devils can be powerful enough to clear away the thin coating of sand and grit covering Mars’ surface, revealing its dark lava or basalt rock beneath. Their powerful gusts may leave dust devil tracks visible for weeks or months after leaving their mark on Mars’ surface.
Dust devils are common on Mars, yet until recently have been hard for scientists to study closely. Scientists have collected images, weather data and dust measurements on them; however, sound has been an element missing until now.
One of Mars’ rovers, Perseverance, recently recorded sounds that revealed an enormous dust devil with its SuperCam microphone on September 27, 2021. Analysis revealed that this storm towered 390.4 feet (119 meters). Furthermore, Perseverance directly passed beneath this gigantic dust storm which eventually dissipated as soon as it hit Perseverance.
This discovery marks a monumental leap forward in understanding these short-lived dust storms. Acoustic signals recorded at the event reveal that the dust devil had at least 25 meters in size and passed the rover at 5 metres per second – indicative of being an extremely strong, fast moving vortex of airflow.
Acoustic signals are ideal for resolving the rapid winds that produce vortices, complementing measurements from Mars Environmental Dynamics Analyzer sensor onboard the rover and providing an additional method to determine their size and trajectory.
Researchers also utilized soundwaves for the first time ever in measuring how fast dust devils move, which provides important insight into their effect on Martian atmospheric and climate over long timescales. Prior to that, scientists measured only wind speed on Mars to gauge changes to dust density levels.
Brain Terrain
An incredible image of Mars shows off its bizarre brain terrain. This mysterious surface resembles the colors and folds found within human brains; unfortunately there’s no clear explanation as to why such land features exist on Red Planet.
There’s the possibility that chunks of ice under Martian soil vaporize when warm air hits them, though scientists also suspect icy ground fractures at low temperatures, with dust flying off windborne into polygonal patterns on landing.
“Brain terrain” refers to an intricate surface made up of pits, buttes, labyrinthine ridges and troughs with pitted surfaces on Mars’ surface that has pits, buttes, labyrinthine ridges and troughs as deep as several meters wide that has pits as pit fill. It typically forms along debris aprons, valley fills or concentric crater fills (Dobrea et al. 2007, Levy et al. 2010).
These ridges and troughs were formed by a layer that once covered much of Mars. It may have formed due to stress cracks forming in its crust that eventually fractured into rocks and ice fragments.
Once a layered unit has stopped covering the surface, 3-5 meters high maze-like ridges begin to appear, usually open but sometimes closed-cell. They may contain cores of ice which eventually melt away leaving narrow ridges behind.
Ridges on Mars can sometimes span 100 meters wide depending on their density; these formations represent the glacial history of its northern hemisphere.
Researchers theorize that the ridges were part of a large ice deposit. Their perimeters often comprise dirt and rock.
As a result, they can be extremely beautiful; some resembling riverbed troughs. Some even feature hollowed-out sections, creating the impression of having been cut directly out from earth itself.
Potentially, some of these ridges could contain water for future explorers on Mars’ surface to use as drinking sources, and/or serve as energy sources for spacecraft on its surface.
Ice Cliffs
Mars is covered with a thin layer of ice that lies hidden under its dusty surface. But occasionally glimpses can be seen peeking out from cliff edges. Here is an image from HiRISE (High-Resolution Imaging Science Experiment), NASA’s Mars Reconnaissance Orbiter camera showing this phenomenon clearly visible ice formations on Mars.
Discovered while investigating eight steep cliffs on Mars which had been eroded to reveal layers of silvery-blue material covered with rock and dust, our team determined that these scarps exposed massive subsurface ice sheets measuring at least 100 meters deep.
Scientists were unaware of how extensive these ice deposits are; however, they could hold key clues to our planet’s past climate and provide a historical record of changes in water and chemical changes as its atmosphere evolved over time.
Researchers claim that this ancient ice formation, originally created as snow long ago and preserved over time by being covered with layers of dust, formed long ago and remains in tact today. Unfortunately, due to erosion processes it appears as though this sheet is receding each year.
These deposits of frozen water may not be accessible to humans, but could prove valuable resources for future rovers or robot explorers who visit Mars in the future. Furthermore, they could contain air bubbles from its atmosphere which could provide another valuable research source.
If the ice is of sufficient quality and can be filtered, it could provide drinking water on Mars. However, high salt levels would necessitate desalination equipment being transported with any spacecraft that explores Mars.
This discovery is highly intriguing and indicates that water may exist abundantly at mid-latitudes on Mars in cliff formations at mid-latitudes. This information will prove invaluable for planetary scientists as well as any colonists hoping to explore this Red Planet in depth.
These findings come at a time when planetary scientists are growing increasingly intrigued by the possibility of sending humans to Mars. With vast deposits of ice beneath its dusty surface, future missions become more likely and thus plausible.
Large Mounds
Mars may be famous for its impact craters and huge impacts, but its surface also boasts stunning valleys like Valles Marineris Canyon that are equally remarkable. Here is one example that captures our attention.
This massive canyon spans 600 km (340 mi), is eight km deep, and eight km wide – nearly double the size of Earth’s own Grand Canyon!
But this valley is no ordinary valley: It’s the largest in our Solar System!
NASA’s HiRISE camera captured this breathtaking photograph from NASA, which compares it to Earth’s Colorado River: Tithonium Chasma is found within Valles Marineris canyon on Titan.
HiRISE camera aboard Mars Reconnaissance Orbiter captured this photo of an interesting feature found within Mars Reconnaissance Orbiter: the Chasma. As one of nature’s spectacular geological formations, its beauty can only increase with age and exposure.
Some of the first impacts to occur on Mars have occurred here and can be clearly seen here.
These impacts have created numerous gullies, and scientists are trying to figure out why and how these changes affected climate.
Gullies on Mars are caused when large chunks of rock hit its surface and burn up in its thinner atmosphere, creating large craters like this one.
Many craters on Mars differ significantly from the ones found on Earth due to the way in which their rock has been blasted away, often appearing circular in shape and sharing similar properties as scoria cones on Earth.
Mars hosts several large mounds that provide insight into what its history may have looked like in past eras. Such features can be very striking and offer us an opportunity to glean information on what the planet looked like then.
Some of these mounds resemble cratered summits, truncated summits or conical summits and feature numerous topographic features such as ridges and gullies.
These features serve as an indicator of the Martian landscape’s evolution over time and offer evidence of water running across its surface millions of years ago, carving canals across its terrain.