Mission Basics
Terms
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- meteoroid
- a small rocky object orbiting the Sun; smaller than an asteroid
- sublimation
- the process of an ice (solid state) turning directly to a gas state; does not change to a liquid first
- declination
- the label for the Y axis on star charts; similar to latitude on Earth
- particle
- a tiny quantity of a substance
- coma
- a cloud that forms around a comet's nucleus made of dust and gas
- aerogel
- a material made of silicate dioxide used to catch comet dust
- Oort Cloud
- a spherical cloud containing cometary particles; goes beyond the orbit of Neptune and Pluto; possibly the source of long period comets
- perihelion
- the point where an object orbiting the Sun is closest to the Sun
- orbit
- the path an object makes as it revolves around the Sun
- nucleus
- the solid part of a comet, made of ices and rock; melts near the Sun
- mass
- a measure of an object's inertia
- long period comets
- a comet with an orbial period of more than 200 years; possibly start in the Oort Cloud
- Kuiper Belt
- a region past the orbit of Neptune containing many small icy bodies; the possible source of short period comets
- gravity
- the force of attraction between two objects
- ejecta
- the debris that is ejected from the site of impact when a crater forms
- astronomical unit (AU)
- a measurement; one AU is equal to the average distance between the Sun and Earth; 93 million miles
- asteroid
- a body orbiting the Sun made of rock
- circle
- a geometric shape; all points are the same distance from the center
- eccentricity
- a numerical vaule for the shape of an orbit; zero to one
- densisty
- the mass of a substance for a given volume
- right ascension
- the label for the X axis on star charts; similar to longitude on Earth
- meteor
- a bright streak of light in the sky caused by a meteoroid entering Earth's atmosphere; shooting star; falling star
- meteorite
- the rocky remains of meteors that land on Earth
- tail
- a long trail of dust and gas that extends out from the coma of a comet when it's near the Sun
- magnitude
- a numerical value for the brightness of a celestial object; brighter is a smaller magnitude, dimmer is a larger magnitude
- constellation
- a group of stars that form a pattern in the sky
- short period comet
- a comet with an orbital period of less than 200 years; periodic comet
- spectrometer
- an instrument used to obtain and record a spectrum (series of colors)of an astronomical object
- periodic comets
- a comet with an orbital period of less than 200 years; a short period comet
- ellipse
- a geometric shape; all points on the curve are the constant sum of the distances from the focal points
- comet
- an object in the Solar System formed of dust, rock and ice