THE FINAL GLOSSORY TERMS (CHAPTER 9)

The galaxy that includes the solar system; appears as a hazy white band in the night sky

A huge collection of stars, planets, gas, anddust that is held together by gravity.

A super cluster is a collection of stars held together by gravity.

A open cluster is a collection of 50 to 1000 stars; open clusters appear along the main band of the Milky Way.

a globular cluster is a collection of 100000 to a million stars that is arranged in a distinctive spherical shape; globular clusters are around the centre of the Milky Way.

A local group is the small group of about 40 galaxies that includes the Milky Way.

A super cluser is a gigantic cluster of 4 to 25 clusters ofgalaxies that is hundreds of millions of light-years in size.

• Spiral: A spiral shape has a central bulge and curved arms sticking out creating a spiral shape.
• Eliptical: Spherical or like a foot ball
• Irregular: No specfic shape

Cosmology is the study of the universe.

This is the change in pitch of a sound due to the motion of the source relative to an observer; also, the change in frequency of a light source due to its motion relative to an observer.

Redshift is the effect in which objects moving away from an observer have their wavelengths lengthened, toward the red end of the visible spectrum.

Blue Shift is the effect in which objects moving toward anobserver have their wavelengths shortened, toward the blue end of the visible spectrum.

The big bang is the event that may have triggered the expansion of the universe 14 billion years ago.

CMB is the radiation left over from the big band, which fills the universe.

Dark Matter is the most abundant form of matter in the universe,invisible to telescopes.

Dark Energy is a form of energy that makes up nearly three of the universe; has effect of increasing the expansion of the universe.