Space Exploration Definitions Flashcards
Solstice
When the sun is at the highest or lowest point in the sky at noon about two times a year (June 21 and December 21)
Equinox
When day and night are equal length two times a year (March 21 and September 22/23)
Geocentric
A model of the universe where the Earth is at the center of our planetary motion
Heliocentric
A model of the universe where the Sun is at the center of our planetary motion
Ellipse
A squashed, imperfect circle that is our planetary motion
Astronomical Unit (AU)
The distance between a planet and the sun
Light-Year
The distance light travels in one year
Nebulae
A cloud of dust/gas that is visible to us from space
Interstellar Matter
The matter and radiation that exists in space between the star systems in space
Protostar
The first stages of the formation of a star where mass of gas starts to contract
Sun-Like-Star
Stars that have characteristics similar to the sun
Massive
Large Mass/Very Big
Main Sequence
A series of star types where in the upper left are hot bright stars and in the lower right is cool dim stars
Red Giant
A large star that is very bright, but has a low surface temperature
Red Super giant
The largest star in the universe with about 15 solar masses and is brighter than the sun
