The idea that there was abundant life on Mars billions of years ago continues to intrigue scientists. Today, the red planet’s cold, dry landscape, stripped of its once powerful magnetic field, raises questions reminiscent of space forensics. Researchers are particularly interested in understanding whether Mars is habitable, and if so, for what period of time.

magnetic field of mars

A research group at Harvard’s Paleomagnetic Research Laboratory within the Department of Earth and Planetary Sciences has been at the forefront of exploring this time scale. A recently published article Nature Communication It provides the most convincing evidence yet that a life-sustaining magnetic field, or “dynamo,” may have existed on Mars about 3.9 billion years ago.

This contradicts earlier estimates that the dynamo died out about 4.1 billion years ago; This shows that the dynamo lasted hundreds of millions of years longer than previously thought.

Modeling the Mars dynamo

The study was led by Griffin Institute of Arts and Sciences student Sarah Steele, who used computer modeling and simulation to determine the age of the Martian dynamo. A Martian dynamo similar to Earth’s, driven by convection in the planet’s iron core, could protect the surface from harmful cosmic rays that are critical to maintaining a habitable environment.

Steele, along with senior author Roger Fu, professor of natural sciences, challenges popular theories that Mars’ magnetic field weakened early. His research involves modeling cooling and magnetization processes in surface craters on Mars. Previously studied shock basins on the planet are known for their weak magnetic fields; This leads to the assumption that they formed after the planet’s dynamo stopped.

Magnetic fields preserved in rock

Paleomagnetism, which involves the study of ancient magnetic fields preserved in rocks, formed the basis for these hypotheses. According to experts, ferromagnetic minerals in the rock align with magnetic fields when heated, and when the rock cools, this alignment “freezes” in place.

Such fossilized magnetic signatures can be examined billions of years later and reveal the state of the magnetic environment at the time the rock was formed. Weak magnetic signals observed in some craters on Mars led researchers to hypothesize that these features formed in the absence of an active dynamo.

But Steele’s team offers an alternative explanation: These basins may have formed during a polar reversal, when the north and south magnetic poles switched places. These changes occur periodically on Earth, and simulations show that they could explain the weak magnetic fields found in Martian craters.

Resident Mars: Changing Perspective

According to Steele, this finding challenges long-held ideas about when the Martian dynamo stopped. “In fact, we show that there may never be a good reason to think that the Martian dynamo will shut down sooner,” he said. This new interpretation builds on the team’s previous work, which questioned Mars’ established habitability scale for the first time.

His previous research included examining the famous Martian asteroid Allan Hills 84001 using an advanced quantum diamond microscope in Fu’s laboratory. The analysis revealed distinct magnetic properties of the rock, indicating a magnetic field that lasted about 3.9 billion years ago.

Value of magnetic fields of planets

Steele acknowledged that challenging a widely accepted theory can be difficult. But he noted that the planetary research community supports new perspectives.

“We’re trying to answer fundamental and important questions about how things got to be this way, why the entire solar system is the way it is,” Steele explained. Magnetic fields play an important role in these studies because they shed light on the deep interiors and early history of planets.

The potential implications go beyond Mars. Understanding the nature and longevity of magnetic fields on other planets helps scientists draw parallels and contrasts with Earth’s history. These findings also contribute to the search for habitability on planets outside our solar system and suggest that the presence and persistence of the magnetic field may be a vital indicator of Earth’s life potential.

Steele and his team’s research is a testament to how scientific thinking evolves with new data and innovative methodologies. By reexamining the nature and duration of Mars’ magnetic field, they open new ways to understand the planet’s ability to support life billions of years ago.

This deeper exploration of planetary history underscores the need for continued research and creative approaches to age-old questions in planetary science. The findings offer a renewed lens to look at Mars’ ancient environment, ultimately bringing researchers closer to unraveling the planet’s mysterious past and its implications for life beyond Earth.