Ellipticals are actually the most numerous type of galaxy. They show no trace of spiral arms; they are instead spherical or ellipsoidal, and resemble the nucleus and halo parts alone of spiral galaxies.
It is thought ellipticals contain only old stars - star formation in these galaxies has come to a virtual halt. The major difference between ellipticals and spirals may be that ellipticals are rotating much more slowly, and therefore have not flattened out into a disk, and a much greater percentage of the gas they contain has condensed into stars (Abell, p. 610).
Ellipticals range from dwarfs much smaller than the smallest spirals, as small as 5,000 light years across, to the rare giant ellipticals like M 87, several hundred-thousand light years across, larger than any spiral.
Messier Catalog Home
Bruton's Home Page