General Asronomy

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35 nadir

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the point in the celestial spher directly beneath the observer, opposite the zenith

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34 zenith

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the point in the sky directly above the observer, opposite the nadir

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33 waxing moon

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any phase during with the illuninationfraction of the face increases

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32 umbra

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the dark shadow of an opaque body,ehere diret light from the source of illuminationis completely cut off

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31 star trails

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a streak made by stars on photographs of the sky, caused b Earth’s rotation

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30 solar corona

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a faint halo of gases surrounding the sun visible during a toatal solar eclipse

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29 penumbra

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the light shadow outside the dark shadow of an opaque body, where the light from te source of illumination is partially cut off

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28 partial lunar eclipse

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an eclipse in whic only part of the moon enters the umbra and isdarkende

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27 meteor shower

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an eventcaused by the earths passage through the orbit of a comet, where it will collide with an increased number of meteoroids, it happens at the same piont in the Earth’s orbit and thus on the same date every year

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26 meteoroid

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a rock in space on a collision couse with the earth, sources of meteorids include comets and colliding asterois

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25 meteorite

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a meteorid that reaches the surface of the Darth or another planet or moon

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24 meteor

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the luminous trail of heated air produced by a meteoroids passage through the earth’s atmosphere

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23 lunar eclipse

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an eclipse in which parts of the Moon are darkened be the Fearth’s shadow, lunar eclipses occur at times of the full moon

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22 gibbous moon

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a phase between quarther and full that shows a surface that is more than half illuminated

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21 fixed star

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a star that occupies a fixed point on the celestial sphere

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20 equinox

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the time when the sun crosses the plane of the earth’s equator making night and day of approximately equal lenght all over the world

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19 eclipse

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the darkening of a celestial body as it passes throughthe shadow of another body, the obscuration of all or part of the sun by a celestial body

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17 circumpolar stars

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stars that never rise or set because their star trails do not intersect the horizon
18 comet massof fromzen gases revolving around the sun, generally in a highly eccentric orbit

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16 centripetal force

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the force acting upon a body moving along a curved path that is directed toward the center of curvature of the pathe and constains the body to the path

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14 barycenter

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the center of mass in a system of two orbiting bodies
15 celestial sphere a huge, imaginary sphere around theEarth, used to model the positions and motions of celestial bodied

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13 asteroid belt

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a band between mars and jupiter where most asteroids orbit

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12 asteroid

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a small, rocky chunk of matter orbiting the sun, also called a minor planet, most asteroids orbit in the asteriod belt

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11 X Ray Binary star

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are special type of binary star in which one of the stars is a collapsed object such as a white dwarf, neutron star, or black hole. As a matter is stripped from the normal star, it falls into the collapsed star, producin X Rays

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10 Eclipsing Binary

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two close stars that appear to be a single star varying in brightness. The variations in brightness is due to the stars periodically obscuring or enhancing one another. The binary star sysetem is titledso that its orbital plane is viewed from its edge.

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9 Binary star

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is a system of two stars that rotate around a common center of mass. About half of all stars are in a group of at least two stars Polaris is an example.

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8 Double star

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two stars that appear close to one another in the sky. Some are true binaries, others just appear together from the Earth because thy are both in the same line of sight

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7 pulsar

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a rapidly spinning neutron star that emits energy in pulses

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6 Neutron Star

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a very small, super dense star which is composed mostly of tightly packed neutrons has a thin atmosphere of hydrogen. It has a diamerter of about 5-10 miles and a density of 10000000000000000gm/cm3.

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5 Brown Dwarf

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a star whose mass is too small to have nuclear fusion occur at its core. They are not very luminous.

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4 White Dwarf

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a small, very dence, hot star that is made mostly of carbon

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3 supergiant

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the largest known type of star;some are almost as large as our entire solar system. Betelgeuse and Rigel are these.

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2 Red Giant

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a relatively old star whose diameter is about 100 percent bigger than it was originally, and had become cooler. they are frequently orange in color. Betelgeuse is one.

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1 red dwarf

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a small, cool very faint, main sequence star whos surface temp. is under 4000k. Red dwarfs are the most common type of star. Proxima Centauri is one.