A new study conducted by the University of British Columbia gives some new findings on Mars’s magnetic history. Mars may have had a magnetic field much earlier than we previously thought. And it may have even lasted longer than earlier calculations. We are getting closer to understanding Mars’s internal magnetic behavior.
Life sustains on earth because the earth’s active magnetic field deflects solar wind and charged particles released from the sun. Meanwhile, Mars has remained a dry land with no atmosphere for billions of years. Mars has almost no measurable fields. But studies show that this has not been so once upon a time. Mars once had a sufficiently strong magnetic field that could help it sustain a stable atmosphere and possibly liquid water!
A planet’s global magnetic field is the magnetic field that extends from its interior and outer space. This phenomenon is based on the dynamo theory. According to this, the liquid rock and metal under a planet’s surface go through rotation and convection. Then, using the principle of electromagnetic induction, a magnetic field is generated over astronomical time scales. Mercury, Jupiter, Saturn, Uranus, and Neptune also have magnetic fields.
To shield itself from the Sun’s wrath, Mars had a powerful magnetic crustal field working to create fields of magnetism.
The absence of crustal magnetic fields over some Martian basins formed 3.9 billion years ago. (According to a recent paper published in Science Advances). This led researchers around the world to believe that the dynamo on Mars was inactive by then. The timeline of the dynamo was expected to be between 4.3 and 4.2 billion years ago.
Researchers of the UBC analyzed the magnetic field data from the Mars Atmosphere and Volatile Evolution (MAVEN) satellite. They found that weak magnetic fields were present over one of the oldest features on the planet.
- Borealis basin, which is 4.5 billion years old.
- Lucus Planum, which is 3.7 billion years old.
So, it showed that a dynamo was present on the planet during a broader time frame. Both before and after the formation of the Hellas, Utopia, Argyre, and Isidis basins.
This could happen only in two scenarios. One possibility is that the dynamo may have stopped before the formation of the basins and restarted before Lucus Planum formed. Or, the creation of the basins somehow displaced the crust that had the minerals required to carry magnetism.
This blog is an excerpt from an article published on Firstpost.