1. The height above a planet's surface.
3. A material of very low electrical conductivity.
5. The abbreviation for electromagnetic radiation with wavelengths 
   that are just a little shorter than visual light.
8. The planet closest to the Sun.
11. Part of a planet's atmosphere where its gas is at least partially
    electrically charged.
12. The seventh planet from the Sun.
15. The abbreviation for 21 Down.
16. Something that occurs in an electrically charged gas in which 
    the vibration of the magnetic field part of it is perpendicular 
    to the direction of travel of it. (2 words)
17. Mercury and Earth are examples of  one of these.
18. The abbreviation for the amount of energy needed to move an 
    electron through a one volt electrical potential.
19. The layer of gas and dust (100's of thousands of kilometers across)
    surrounding a comet nucleus.
20. ____-8. A NASA spacecraft launched in October 1973, in order to study 
    the space around the Earth out to about the distance of the Moon.
22. A spacecraft built by the European Space Community and launched in 
    December 1995.
23. A process by which an atom or ion is raised to a higher energy state.
25. The abbreviation for a period of time encompassing parts of years 1957 
    and 1958; this marked the beginning of major cooperation in the Space 
    Age among space and Earth scientists.
27. An atom (or molecule) that has lost or gained one or more electrons and
    therefore is electrically charged.
29. The regions in the magnetosphere of a planet where the magnetic field 
    lines of force have a geometrical shape like a funnel.
30. The smallest particle into which an element can be broken.
31. These goes through a spectrum of types called super high, ultra high, 
    very high, medium, low, and very low.  (2 words)
35. Along with protons, this is the other principal component particle of 
    atomic nuclei.
36. A very general term which can be used in connection with other forces 
    in physics such as electric force or magnetic force. (2 words)

1. The gas envelope that surrounds a body in space which is held to that 
   body by gravity.
2. The product of force, acting about some axis, and some distance 
   representing a lever.
3. The process that forms an ion out of an atom or molecule.
4. _____ stabilized is a spacecraft that rotates at some constant period 
   about one of its principal axes.
6. Launched in August and September of 1977 planned for visits to Jupiter 
   and Saturn. (2 words)
7. The abbreviation (of 3 words) for bundles or clouds of electrically 
   charged gas ejected from near the Sun's surface.
9. This has magnetic field lines of force passing from the solar wind 
   into and out of the magnetopause boundary. (2 words)
10. Refers to something, usually a particle, moving at a speed near the 
    speed of light.
13. The abbreviation for a unit of electrical current equivalent to about 
    6 X 1018 electrons per second.
14. The nearest star to our planet.
19. The atmosphere of the Sun that can be observed out to many times the 
    size of the Sun's main surface.
21. The mass of a thousand grams.
22. An electrically charged gas that usually blows almost directly outward 
    from the Sun.(2 words)
24. Anything having to do with the Earth.
26. A Japanese spacecraft, with significant U.S. and U.K. contributions,
    launched in 1991 that performs dynamic x-ray imaging of the Sun.
28. These are very high frequency electromagnetic waves with very small
    wavelengths. (2 words)
32. An oscillatory motion of something in nature.
33. A natural satellite orbiting around a planet.
34. The abbreviation for the solar wind that lies outside of the bow shocks of planets.