Life May Have Thrived on Mars Billions of Years Ago

The search for life on Mars has taken a step forward, with new research suggesting the red planet may have been habitable until much more recently than previously believed. A recent study indicates Mars might have supported life billions of years ago, leaving scientists with the question of when and why that environment changed.

In a study led by Sarah Steele, a graduate student at Harvard’s Paleomagnetics Lab within the Department of Earth and Planetary Sciences, researchers estimate that Mars’ life-supporting magnetic field, or “dynamo,” could have lasted until about 3.9 billion years ago.

This is a few hundred million years more recent than prior estimates of its end around 4.1 billion years ago. The findings, published in *Nature Communications*, suggest the Martian dynamo, generated by the planet’s iron core, was capable of protecting Mars from cosmic radiation for longer than previously thought.

To arrive at this new timeline, Steele and her team used simulations and computer modeling to estimate the age and duration of Mars’ magnetic field. The team simulated the cooling and magnetic cycles of Martian craters, which currently show only faint magnetic fields, suggesting these craters were formed after the dynamo shut down.

The researchers propose that the planet’s weak magnetic signals might be explained by magnetic pole reversals, during which Mars’ north and south poles would have switched places, similar to Earth’s magnetic field flips every few hundred thousand years.

Lead researcher Roger Fu, a professor of natural sciences at Harvard, explains that understanding planetary magnetic fields offers crucial insight into a planet’s early history and interior structure. “Planetary magnetic fields are our best probe to answer a lot of those questions,” Steele added, highlighting how these findings contribute to our knowledge of not just Mars, but the broader solar system’s formation and evolution.