Scientists have been studying the red planet since the 1960s. How much is Mars really like Earth? Could our solar system neighbor become a travel destination in the future? Could we live there? Ask Science investigates the Martian habitat.
In February of 2019, NASA scientists made one last attempt to contact the Opportunity rover after thousands of previously unanswered calls. When they again didn’t hear back, the mission was officially ended. Eight months earlier, a planet-wide dust storm had ravaged the Martian surface, coating the rover’s location in a thick layer of dust. With dust coating its solar panels, Opportunity was no longer able to power its communications with Earth or its exploration of the Martian surface.
When the Spirit and Opportunity rovers reached the Martian surface in 2004, their mission was expected to last for 90 days and 1,000 meters or 1,100 yards. Opportunity ultimately roamed the red planet for over 15 years and traveled 28 miles returning more than 217,000 images of its adventures back to us here on Earth.
Mars is the most studied planet beyond our own. The first successful mission dates back to 1965 with the Mariner 4 flyby. One of the biggest questions that motivates our exploration of Mars through programs like the rovers is: Can we live there? How much is Mars really like Earth?
Let’s take a look at some of the key planetary characteristics that determine whether or not Mars is habitable and how the red planet compares to Earth.
Mars Is Cold
Humans need water to survive, so a hospitable planet for us must support temperatures where liquid water can exist. Mars is farther from the Sun than Earth is (1.5 times as far), so it takes longer for the red planet to orbit around our shared star. In fact, a year on Mars is 687 Earth days. So if you’re 30 years old on Earth, you’d only be 16 on Mars (that's the good news).
The not so good news is that this extra distance from the Sun means temperatures on Mars run colder than on Earth. Temperatures on the red planet can span from a frigid -195 degrees Fahrenheit in winter near the polar ice caps to a comfortable 70 degrees Fahrenheit in summer near the Martian equator.
A year on Mars is 687 Earth days. So if you’re 30 years old on Earth, you’d only be 16 on Mars (that's the good news).
Somewhat similar to Earth, Mars is also a dynamic planet: it has storms, winds, volcanoes, and even seasons. A hugely important result from the our Martian explorations has been the evidence that Mars was once warmer, wetter, and had a thicker atmosphere. Opportunity found hematite at its landing site, a mineral that forms in water, and evidence of ancient water at Endeavour Crater much like a pond here on Earth.
But now the planet is a dry and dusty desert. Water at the surface is found either locked up in the polar caps as ice or as scant amounts of water vapor in the atmosphere. Even the dark streaks found trailing down the Martian dunes that were once thought to be evidence of recent seasonal liquid water flow are now argued by some to be formed by sand instead.