| A | B |
|---|
| Scientists think that the universe will | expand forever |
| what does a stars color indicate | temperature |
| the H-R diagram shows the relationship between a star's surface temperature and its | absolute magnitude |
| which star is the hottest | white dwarf |
| Scientists think the Milky Way is probably | a spiral galaxy |
| Which is the largest - nebula, galaxy, neutron star, globular cluster | galaxy |
| On what part of the modern H-R diagram do cool bright red stars appear | bottom right |
| what is one way scientists use to calculate the age of the universe | measure the distance frm Earth and various galaxies |
| why d black lines appear on an absorption spectrum | black lines appear where colors of light are absorbed by a star's atmosphere |
| What do the pattern of lines in a star's absorption spectrum represent | some of the elements in the star's atmosphere |
| elliptical galaxies and the halos of spiral galaxies contain groups of stars called | globular clusters |
| the universe is organized according to | a loosely arranged structure |
| what are the three major types of galaxies identified by Edwin Hubble | spiral, elliptical, irregular |
| why do scientists study distant galaxies to learn about early galaxies | because it takes along time for light to travel through space looking at distant galaxies shows what early galaxies looked like |
| what type of star has used up all its hydrogen and is a leftover center of an old star | white dwarf |
| the distance that light travels in one year about 9.5 trillion kilometers | light year |
| an object so massive and dense that not even light can escape its gravitational pull | black hole |
| a distant star- like source of light | quasar |
| the brightest star as seen from Earth | apparent magnitude |
| the diagonal pattern on the H-R diagram where most stars appear | main sequence |
| the brightness of a star at a distance of 32.6 light year's from Earth | absolute magnitude |
| what binds a galaxy together | gravity |
| what classification do astronomers use for galaxies | shape |
| what are individual objects in the universe a part of | a larger system |
| how do scientists tell if a star is cool or warm | color |
| what type of galaxy is the Milky Way | spiral galaxy |
| the H-R diagram graphs what two things | a star's temperature and brightness |
| how long ago did the universe begin | 1 million years ago |
| a tight group of stars | globular cluster |
| a group of closely grouped stars | open cluster |
| a large cloud of dust and gas | nebula |
| a star that is the former center of an old star | white dwarf |
| a star made up of neutrons | neutron star |
| a huge explosion in which a large star dies | supernova |
| a huge object from which light cannot escape | black hole |
| a spinning neutron star that emits pulses of energy | pulsar |
| light travel in one year over a distance is called | light year |
| how bright a star is at 32.6 light year's from earth is called | absolute magnitude |
| how bright a star is as seen from Earth is called | apparent magnitude |
| a star may seem to move in place because of | parallax |
