S u m m a r y :
Mars has a twisted magnetotail—an invisible magnetic tail that results from interactions between the magnetic fields of the solar wind and the planet’s own magnetic activity, says a new study. The research, part of NASA’s Mars Atmosphere and Volatile Evolution Mission (MAVEN), was presented at the 49th annual meeting of the American Astronomical Society’s Division for Planetary Sciences last week.
Mars & Its Magnetic Tail
Red Planet Mars continues to captivate the mind of astronomers, specially that it is suspected to have once retained water and an atmosphere, characteristics that promise the existence of life. Scientists are still trying to understand how it lost its water and atmosphere, turning into a cold and unwelcoming world. Efforts directed towards demystifying Mars include NASA’s MAVEN spacecraft sent into orbit around the planet to capture as much information as possible. The most recent finding involves the discovery of Mars’ magnetic tail, its magnetotail, being twisted.
What is a Magnetotail?
A magnetotail is a tail-shaped extension of a heavenly body’s magnetosphere on the opposite side of the sun. Mars’ magnetotail is different from any found in the solar system, explains MAVEN scientist Gina DiBraccio. It is to be noted that Mars lost its global magnetic field billions of years ago, and it now only has remnants of it in some regions, unlike Earth whose magnetic tail also has an internal magnetic field. The Martian magnetotail also differs from that of Venus, a planet with no magnetic field of its own; rather, it is a hybrid between the two.
Formation of the Martian Magnetotail
So, how is the magnetotail of Mars formed? According to the model of DiBraccio and her team, the formation of the twisted magnetotail is caused by a process known as magnetic reconnection whereby magnetic fields brought by the solar wind (a jet of electrically conducting gas that emanates from the surface of the Sun at 1.6 million kilometers per hour) join with the magnetic fields of Mars.
“Our model predicted that magnetic reconnection will cause the Martian magnetotail to twist 45 degrees from what’s expected based on the direction of the magnetic field carried by the solar wind,” says DiBraccio. “When we compared those predictions to MAVEN data on the directions of the Martian and solar wind magnetic fields, they were in very good agreement.”
How Did Mars Lose Its Atmosphere?
Magnetic reconnection might also be behind the loss of the atmosphere of Mars into space. The electrically charged particles (ions) in the upper atmosphere of the Red Planet would have been affected by electric and magnetic forces, causing them to flow along the magnetic field lines. Given that the Martian magnetic tail is the joining of the planet’s magnetic fields with those of solar winds, the Martian ions have a way into space moving down the magnetotail.