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Glossary

M

MACHOs

Massive Compact Halo Objects

magnetic storms

A large-scale disturbance of the magnetosphere, often initiated by the arrival of an interplanetary shock originating at the Sun.


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magnetopause

The boundary surface between the solar wind and the magnetosphere where the pressure of the magnetic field equals the pressure of the solar wind


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magnetosphere

The region surrounding a celestial body where its magnetic field controls the motions of charged particles.


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magnetotail

The portion of a planetary magnetosphere which is pushed in the direction of the solar wind


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Maunder minimum

A 70-year period from 1645 to 1715 when sunspots were rare.


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MEPAG

Mars Exploration Planning & Analysis Group

mesoscale

Of or relating to a meteorological phenomenon approximately 10 to 1000 kilometers in horizontal extent.


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meteor

Any of the small particles of matter in the solar system that are directly observable only by their incandescence from frictional heating on entry into the atmosphere.


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meteorites

A meteor that reaches the surface of the earth without being completely vaporized.


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meteorology

Study of the atmosphere and its phenomena.


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microphysical

The physics of molecules, atoms, and elementary particles.


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MIDEX

Medium Explorer

Milky Way

The galaxy of which the sun and the solar system are a part and which contains the myriads of stars that create the light of the Milky Way.


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mission

NASA Science-funded activity with the purpose of meeting goals laid out by presidential directive, and detailed in Science Mission Directorate's strategic plan.

mitigate

To cause to become less harsh or hostile.


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ML3N

Mars Long-lived Lander Network

MMS

Magnetospheric Multiscale

modeling

A mathematical representation of a process, system, or object developed to understand its behavior or to make predictions. The representation always involves certain simplifications and assumptions.


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MODIS

Moderate Resolution Imaging Spectrometer

modulated

To vary the amplitude, frequency, or phase of (a carrier wave or a light wave) for the transmission of information (as by radio); to vary the velocity of electrons in an electron beam.


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MU-SPIN

Minority University-Space Interdisciplinary Network