NASA's MESSENGER probe orbited Mercury for four years and crashed into the planet owing to fuel shortage. But the probe has provided important information about Mercury’s magnetic field.

As per the data, the planet’s magnetic field is around four billion years old. The researchers have been utilizing the data gathered by Messenger in the fall of 2014 and 2015 when the probe was quite close to the planet’s surface.

Study’s lead author Catherine Johnson, a University of British Columbia planetary scientist, said that the mission was planned to continue for one year, but it lasted for four years. Johnson said that information of the magnetic field about the planet is just the starting.

Researchers were aware of the fact that the closest planet to the sun has a magnetic field that is similar to earth, but much weaker. Except earth, Mercury is the only planet in the inner solar system having such a type of magnetic field in which the motion of liquid iron present deep inside the planet’s core causes the field.

When the probe was closer to the planet, its magnetometer gathered data on magnetism of rock present on Mercury’s surface. After studying those signals, it was found that Mercury’s magnetic field is quite old and may be between 3.7 and 3.9 billion years old.

The planet was formed around at the same as earth. Johnson said, “If we didn't have these recent observations, we would never have known how Mercury's magnetic field evolved over time. It's just been waiting to tell us its story”.

Johnson said she along with her colleagues will continue to evaluate data from Messenger. They are also looking forward to a 2015 mission to Mercury known as BepiColombo. The mission organized by the European Space Agency unveiled that BepiColombo will assume a more circular orbit around Mercury.