UniverseUniverse

Everything that exists in all space Everything that exists in all space everywhere.everywhere.

GalaxiesGalaxies

Galaxies are large groups (billions) of Galaxies are large groups (billions) of stars bound by gravity.stars bound by gravity.

3 kinds3 kinds SpiralSpiral

Long twisting armsLong twisting arms Center rotates fasterCenter rotates faster

GalaxiesGalaxies

EllipticalElliptical Usually smaller Usually smaller

and stars are and stars are closer togethercloser together

GalaxiesGalaxies

IrregularIrregular Neither spiral, Neither spiral,

nor ellipticalnor elliptical

NebulaNebula

A nebula is a A nebula is a cloud of gas and cloud of gas and dust in outer dust in outer space. space.

These clouds are These clouds are often very large, often very large, spanning across spanning across many light years. many light years.