The Moon does n’t have a magnetic field , but magnetized sway generate by the Apollo missions show it once did . Now , more than 40 yr after humanity last visited the lunar surface , we have an account for how this came to be .
rock candy that formed in the first billion age of the Moon ’s creation are magnetized , exhibit the front of a magnetic field at the meter . At one gunpoint , the playing area may even have transcend the Earth ’s in force . But the field weakened some 3.5 billion days ago , and vanish totally about half a billion years later . geologist have struggled to excuse its cause .
InEarth and Planetary Science Letters , the field is attribute to crystallization occurring within the lunar gist . Dr Kevin Righterof NASA ’s Johnson Space Center and colleagues proposed that the Moon ’s nickel / iron core was down in impurities such as sulfur and carbon , creating a in high spirits thawing tip . The Moon ’s small size compared to planet mean it lose the heating system of shaping relatively cursorily . If Righter is right about the gamy melting point , temperature would have dropped to this point quite early on in the Moon ’s history .
Once the melting point was arrive at , the Moon ’s core started effloresce , and Righter argues that the energy released in this cognitive process drove the magnetic landing field . A squad at Johnson try the idea by heating powders formed from mixtures of the elements consider to have predominated within the Moon ’s interior . As long as the sulfur / carbon copy content was low-toned , crystallizing hap at temperature coherent with the theory . Although the exact composition of the core can not be check in this manner , a run with 0.5 pct sulphur and 0.375 percentage carbon copy by weight had , at naturalistic pressures , a thaw point of 1,550ºC ( 2,822ºF ) . This is high enough to gibe with what we know of the field ’s timing .
Co - authorDr Lisa Danielsondescribed the squad in astatementas “ excited , because this work shows that a specific geochemically - derived composition can explicate many geophysical aspects of the lunar core . ”
This is not the first explanation offer . In 2014 , a modelwas proposedfor a lunar dynamo like to the one opinion to be responsible for the Earth ’s field of study . However , skepticism remained that an object as diminished as the Moon could substantiate the convection forces needed to maintain such a knock-down dynamo , particularly for so long .
Understanding the Moon ’s magnetized history is of more than but theoretical interest . It is more often than not believed that long - endure magnetic fields areessential for aliveness , at least beyond the microbic stage . Understanding the circumstances in which satellite and moons form athletic field can help us predict the scene for life on other worlds .
