Astronomy terms starting with M

18 terms

  1. Magnetic Field A field of force around the Sun and the planets, generated by electrical currents, in which a magnetic influence is felt by other currents.
  2. Magnetic Field Lines A magnetic field has both a strength and a direction at each point in space. For example, at each point Earth, the magnetic field -- and thus a compass --…
  3. Magnetic Loops Field lines illuminated by hot plasma flowing along the magnetic field lines.
  4. Magnetic Storms and Substorms A series of terrestrial disturbances – namely, the precipitation of auroras and rapid changes in Earth's magnetic field – caused by high-speed blasts…
  5. Magnetism A force generated by electrical currents and changing electric fields. Magnetism is responsible for almost every feature in the solar atmosphere, from…
  6. Magnetogram A magnetogram is an image of the Sun's magnetic flux. They are derived by using emission lines which are magnetically sensitive, which allows the magnetic…
  7. Magnetosphere An area around a planet in which the planet’s magnetic field is stronger than the magnetic field carried by the solar wind.
  8. Magnetotail The long magnetic tail of a magnetosphere drawn out by the flow of the solar wind.
  9. Main Sequence Star A star that lies along a continuous band, known as the main sequence, extending from the upper left (hot, bright stars) to the lower right (cool, dim…
  10. Mass Defect When two subatomic particles are bound together, their bound mass is slightly different than their mass if each particle is measured separately.
  11. Matter-Dominated Universe When the density of matter is greater than that of any other component.
  12. Maunder Minimum From 1645 to 1715, scientists believe there was a decrease in the total energy output from the Sun, as indicated by little or no sunspot activity.
  13. Meson A kind of matter made from an even number of quark-antiquark constituents. The basic structure of most mesons is one quark and one antiquark.
  14. Metastable Energy Density A theorized transient energy, often preceding a phase transition.
  15. Mid-Class Explorer (MIDEX) NASA's Mid-Class Explorer.
  16. Milky Way The galaxy in which the Earth is found. When viewed from the Earth and its environs, it appears in the night sky as a hazy band of white light (hence…
  17. model See Exhibit.
  18. Muon The second heaviest charged lepton (with electron and tau), with electric charge -1.