Could Mars be our next home? Five strange facts about the Red Planet that will make you rethink

As our closest planetary neighbor, Mars has long captured humanity's imagination, with space agencies and private players like SpaceX all eyeing a Mars colony sometime in the near future. While Mars's location at the edge of the Goldilocks Zone and its hypothesized history of having liquid water make it an attractive target for colonization, there are some lesser known facts about the Red Planet that might make you think twice.

Mars's dust storms have often been referred to in pop culture and works of fiction, but what is generally not known is that these storms can grow to enormous proportions, sometimes circling the planet itself. These planetary-scale storms, which occur every 5.5 Earth years (roughly three Martian years) according to NASA, can kick up unimaginably massive plumes of dust, blocking 99% of the sunlight hitting the Red Planet and making surface temperatures plummet.

Interestingly, humankind has already had one fateful encounter with such a storm. After over 14 years of service, NASA's Opportunity rover saw its life snuffed out by one of these planetary Martian storms in 2018, which blocked out sunlight and prevented the solar-powered robot from recharging its batteries or keeping its critical electronics warm. Opportunity's fate serves as a reminder that these storms are not to be trifled with: a single global Martian storm could trigger a fatal power-grid collapse in future solar-reliant human colonies.

The image shows a vista of Victoria Crater taken by NASA's Opportunity rover.

While the unforgiving Martian terrain and weather pose their own threats to colonization, an even bigger threat is perhaps the Sun itself. Mars, unlike Earth, does not have a protective magnetosphere, which makes humans on the planet particularly susceptible to space-based radiation. While cosmic rays pose a steady long-term risk for human settlers, solar particle events such as solar flares and coronal mass ejections pose an even bigger threat. Measurements taken by NASA's Curiosity rover have already shown that a single high-energy solar storm can cause surface radiation levels to spike sharply on the Red Planet, suggesting that human settlers will have to take ample precautions if they are to one day establish a presence on Mars.

This image, taken by NASA's Spirit rover in 2005, shows a sunset on Mars.

On Earth, dust is largely considered harmless, but on Mars, it can prove deadly. Even when storms aren't engulfing the entirety of the planet, the dust itself is inherently dangerous. While Martian wind provides some tumbling, without water to extensively weather the grains of minerals, the dust remains highly abrasive. The particles also carry strong electrostatic charges, making them stick to surfaces such as spacesuit fabric and human-made infrastructure. Beyond making everything dusty, these fine particles pose a much more sinister risk: they act as a harsh abrasive, mechanically chewing through spacesuit seals, air filtration systems, and critical equipment. Furthermore, Martian dust is laced with toxic chemicals like perchlorates. Not only is this risk external, but studies also suggest that inhaling these fine, toxic particles inside habitats can result in severe degradation of human respiratory systems. Consequently, learning to manage Martian dust is a critical issue that needs to be solved before humankind can think of establishing any sort of long-term presence on the Red Planet.

The image is an artist's concept illustrating a Martian dust storm, which might also crackle with electricity.

Whereas gravity on Earth helps us develop strong musculoskeletal structures, the gravitational environment on Mars can be punishing. Martian gravity is roughly 38 percent of Earth's, and long-term exposure to this 0.38 g environment has the potential to lead to long-term health risks. A recently published study exploring this very topic found that muscles atrophy at levels lower than 0.67 g, making the Martian environment far from conducive for a human stay. Not only does this highlight risks to adult humans traveling to Mars, it also raises serious questions about the plausibility of long-term presence and colonization, with very little research available on the effects of low gravity on fetal development and birth.

While surface temperatures on Mars can reach a comfortable 20 degrees Celsius in peak summer, the Red Planet is far from a temperate paradise. Due to its extremely thin atmosphere—roughly 100 times thinner than Earth's—Mars cannot trap daytime heat, and as a result, sees wild temperature swings. Temperatures on the Red Planet can change by as much as 100 degrees Celsius between day and night, something that human infrastructure needs to account for. Such temperature swings on a daily basis can create extreme expansion and contraction stress on habitat structures and infrastructure, putting human colonies at severe risk. Additionally, such temperature extremes also drastically reduce the margin for error: even a small power grid failure during Martian night could potentially cause rapid freezing of water sources, crack structural materials, and cause fatal hypothermia, leading to the rapid collapse of colonies.

This image, combining data from two instruments aboard NASA's Mars Global Surveyor, depicts an orbital view of the north polar region of Mars.