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Highland 6th Space
The Universe and its components
Term | Definition |
---|---|
Galaxy | A large group of stars, gas, and dust held together by gravity. |
Gravity | The natural force of attraction exerted upon objects at or near its surface, tending to draw them toward the center of the body. |
Light Year | The distance light travels in one year. Used to calculate distances between galaxies. |
Steady State Model | The model of origin of the universe that says our universe is still the same as it was from the beginning. |
Oscillating Theory | The model of origin of the universe that says our universe expands and contracts. |
Big Bang Theory | The model of origin of the universe that says our universe was formed from a big explosion. |
Inner Planets | The four "rocky planets". Mercury, Venus, Earth, Mars. |
Outer Planets | The four "gas giants". Jupiter, Saturn, Uranus, and Neptune. |
Dwarf Planet | Pluto because it is a rocky planet not a gas giant. |
Milky Way | The name of our galaxy. |
Astronomical Unit | The distance from Earth to the Sun, 93 million miles, used to calculate distances between planets. |
Moon | A natural satellite that revolves around a planet. Does not produce its own light. |
Planet | Any celestial body that doesn't produce its own light and revolves around a star. |
Asteroid | A celestial body made of frozen rock and gas that orbits the Sun between Jupiter and Mars. |
Comet | A celestial body made of frozen rock and gas that revolves in an orbit around the Sun. It has a nucleus and a hazy tail which is made of evaporated gases heated by the Sun. |
Meteor | A meteorite that burns up in Earth's atmosphere. |
Meteorite | A meteoroid that strikes Earth's surface. |
Chromosphere | One of the middle layers of the Sun's atmosphere. |
Corona | The top, largest layer of the Sun's atmosphere. |
Photosphere | The lowest layer of the Sun's atmosphere; it gives off light. |
Sunspot | An area on the Sun's surface that is cooler and less bright than surrounding areas. |
Axis | Imaginary center line around which Earth spins. |
Ellipse | Elongated, closed curvy shape that is the orbit of the Earth around the Sun. |
Equinox | Twice yearly time (spring and fall) when the Sun is directly over the equator and the number of daylight and nighttime hours are the same. |
Revolution | The motion of a celestial body around another celestial body. |
Rotation | The spinning of a celestial body on its axis. |
Solstice | The twice-yearly point at which the Sun reaches its greates distance north or south of the equator. |
Sphere | A round, three dimensional object whose surface is the same distance from its center at all points. |
Lunar Eclipse | Occurs ehw Earth passes directly between the Sun and the Moon, and Earth's shadow falls on the moon. |
Solar Eclipse | Occurs when the Moon passes directly between the Sun and Earth and casts a shadow over part of the Earth. |
Maria | The dark-colored, flat region of the Moon. |
Moon Phase | Change in appearance of the Moon as viewed from the Earth, due to the relative positions of the Moon, Earth, and Sun. |
Waxing phase | Describes phases of the Moon as more of the reflected light becomes visible. |
Waning phase | Describes phases of the Moon that occur when less of the reflected light is visible from Earth. |