science(ch 1 sec 3) Flashcards
astronomy
the study of the universe
year
the time required for the Earth to orbit once around the sun.
month
roughly the time required for the moon to orbit the Earth once.
day
the time required for the Earth to rotate once around on its axis
telescope
an instrument that collects electromagnetic radiation from the sky and concentrates it for better observations.
refracting telescope
a telescope teat uses a set of lenses to gather and focus light from distant objects.
reflecting telescope
a telescope that uses a curved mirror to gather and focus light from distant objects.
electromagnetic spectrum
all of the wavelengths of electromagnetic radiation.
constelation
a region of the sky that contains a recognizable star pattern.
zenith
an imaginary point in the sky directly above an observer on Earth.
altitude
the angle between the zenith and horizon.
horizon
the line where the sky and the Earth appear to meet.
light-year
the distance that light travels in one year; about 9.46 trillion kilometers.
