Term |
Definition |
astronomy |
the study of all physical objects beyond earth |
astronomer |
someone who studies space/heavens |
revolution |
the elliptical motion of a body as it orbits another body in space |
rotation |
the spinning motion of a body on its axis |
orbit |
the elliptical path a body takes as it travels around another body; the motion itself |
calendar/gregorian |
a system for organizing time |
year |
the time required for the earth to orbit the sun once |
month |
the time required for the moon to orbit the earth once |
day |
the time required for the earth to rotate once on its axis
|
heliocentric |
sun centered |
geocentric |
earth centered |
astrolabe |
handheld tool invented by the arabs used to measure the stars |
horizon |
the line where the sky and earth appear to meet |
zenith |
an imaginary point in the sky directly above an observer on earth |
altitude |
the angle between the object and the horizon |
azimuth |
imaginary circle that forms exactly around the horizon at 360 degrees |
celestial sphere |
stars in a sphere shape around earth |
declination |
a measure of how far north or south an object is from the celestial equator |
right ascension |
measure of how far east an object is from the point at which the sun appears on the first day of spring |
telescope |
instrument that collects electromagnetic radiation from the sky and concentrates it for better observation |
optical telescope |
telescope that collects visible light for closer observation |
electromagnetic radiation |
radiation from the sun |
star maps |
circular maps the marked stars by hemisphere |
astronomical unit |
way to measure units to planets (sun to planet) |
light year |
distance light travels in a year (6 trillion miles/year) |
big bag theory |
the theory that states the universe began with a tremendous explosion |
nebula |
a large cloud of dust and gas in interstellar space (where stars are formed) |
solar system |
the system composed of the sun and the planets and other bodies that travel around the sun |
galaxy |
a large grouping of stars in space |
star |
huge, hot, brilliant balls of fire |
planet |
celestial body that orbits a star |
moon |
natural satellite |
asteroid |
small, rocky body that revolves around the sun |
meteoroid |
small, rocky body orbiting the sun |
meteorite |
meteoroid that strikes earths ground |
meteor |
when meteoroid moving towards earth at a fast pace and light comes off of it |
fusion |
energy from a star |
satellite |
a natural or artificial body that revolves around a planet |
space probe |
a vehicle that carries scientific instruments to planets or other bodies in space |
comet |
planetesimals made of ice, 'dirty snowballs' |
seasons |
4 divisions, weather patterns/daylight hours |
tilt |
cause to move into a sloping position |
planetesimals |
the tiny building blocks of the planets that formed as dust particles stuck together and grew in size |