Card Set Information
Astronomy intro ChapterOne
introduction to astronomy and the units to measure distance on an astrological scale.
Small non luminous bodies that shine by reflection
the sun, it's family of planets, and some other bodies, such as moons, asteroids, and comets.
a self-luminous ball of hot gas that generates it's own energy
Astronomical Unit (AU)
1.5 x 10^8 kilometers (93 million miles)
average distance from Earth to the Sun
Light Year (ly)
the distance that light travels in1 year
roughly 10^13 km or 63,000 AU
in a photo, what does the size of a star represent
not the actual size of the star, but its brightness of the star
How many stars does our galaxy contain?
more than 100 billion
a large system of stars, star clusters, gas, dust, and nebulae orbiting a common center of mass.
Milky Way Galaxy
the spiral galaxy containing our sun, visible in the night sky as our galaxy.
long spiral pattern of bright stars, star clusters, gas, and dust. Spiral arms extend across the disks of spiral galaxies.
clusters of clusters of galaxies
3.1 x 10^13