Would you be interested in being one of the first humans to explore Mars? Why or why not?
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MARS HAS CAPTIVATED humans since we first set eyes on it as a star-like object in the night sky. Early on, its reddish hue set the planet apart from its shimmering siblings, each compelling in its own way, but none other tracing a ruddy arc through Earth’s heavens. Then, in the late 1800s, telescopes first revealed a surface full of intriguing features—patterns and landforms that scientists at first wrongly ascribed to a bustling Martian civilization. Now, we know there are no artificial constructions on Mars. But we’ve also learned that, until 3.5 billion years ago, the dry, toxic planet we see today might have once been as habitable as Earth.
Since the 1960s, humans have set out to discover what Mars can teach us about how planets grow and evolve, and whether it has ever hosted alien life. So far, only uncrewed spacecraft have made the trip to the red planet, but that could soon change. NASA is hoping to land the first humans on Mars by the 2030s—and several new missions are launching before then to push exploration forward. Here’s a look at why these journeys are so important—and what humans have learned about Mars through decades of exploration.
Why explore Mars
Over the last century, everything we’ve learned about Mars suggests that the planet was once quite capable of hosting ecosystems—and that it might still be an incubator for microbial life today.
Mars is the fourth rock from the sun, just after Earth. It is just a smidge more than half of Earth’s size, with gravity only 38 percent that of Earth’s. It takes longer than Earth to complete a full orbit around the sun—but it rotates around its axis at roughly the same speed. That’s why one year on Mars lasts for 687 Earth days, while a day on Mars is just 40 minutes longer than on Earth.
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Despite its smaller size, the planet’s land area is also roughly equivalent to the surface area of Earth’s continents—meaning that, at least in theory, Mars has the same amount of habitable real estate. Unfortunately, the planet is now wrapped in a thin carbon dioxide atmosphere and cannot support earthly life-forms. Methane gas also periodically appears in the atmosphere of this desiccated world, and the soil contains compounds that would be toxic to life as we know it. Although water does exist on Mars, it’s locked into the planet’s icy polar caps and buried, perhaps in abundance, beneath the Martian surface.