Scientists at the University of British Columbia have identified the exact time when Mars had a magnetic field. Geomagnetic Dynamo existed 4.5 and 3.7 billion years ago. The results of the study, revealing one of the secrets of the red planet, published in the journal Science Advances.
Experts analyzed multi-year satellite data collected by the spacecraft MAVEN and Mars Global Surveyor and found evidence for the existence of the magnetic field in the region of Lucus Planum formed by a lava flow, which stood less than 3.7 billion years ago. The researchers also found the magnetic field of low intensity over the North Polar pool in the Northern hemisphere of the planet that was formed 4.5 billion years ago and is considered one of the oldest objects on Mars.
It is known that the geomagnetic Dynamo, when the iron core of the planet rotates and the generated magnetic field was active between 4.3 and 4.2 billion years ago, but was not present 3.9 billion years ago. A possible explanation is that a Dynamo in a while would stop and then start again. In an alternative scenario, impacts of celestial bodies, which formed pools has shifted away part of the bark, which contained magnetized minerals.