Lenticular galaxies are either aging spirals or the product of galaxy mergers our own Milky Way and Andromeda galaxies could become lenticular galaxies when they merge in a few billion years. Lenticular galaxies have little ongoing star formation, which you can see in images as the dust lanes lack any bright bluish or pinkish spots corresponding to young blue stars or hydrogen-rich star-forming regions. They have the spherical shape of elliptical galaxies at the center, surrounded by a disk of concentric rings of dust that can look like a spiral when viewed edge-on or an elliptical galaxy if the disk is not very bright. Lenticular galaxies are sort of an intermediate class between elliptical and spiral galaxies and are classified as S0 or ES in the Hubble system. Hubble was also unaware of the differences between dwarf spheroidal/elliptical galaxies and their larger counterparts, which we’ll get into later. Hubble classified some galaxies that were thought to be elliptical all the way to E7, but we know now that those were just lenticular galaxies viewed at an odd angle. Completely spherical elliptical galaxies are referred to as E0 type, flattening out to more oval or American football-shaped galaxies as E1, E2, and so on all the way to E4. Hubble’s system of classifying elliptical galaxies is not based on size, spectrum, or origin but rather on shape and structure (more commonly referred to as “morphology”). By contrast, dwarf elliptical galaxies are frequently found circling larger spiral or elliptical galaxies. Giant elliptical galaxies make up some of the largest galaxies in the universe. This is probably the only classification you’ve ever heard of, but it’s a little incomplete.Įlliptical galaxies are galaxies with little dust and gas left. He came up with a system that is used even today. In 1926, around the same time that it was proven that the odd “spiral nebulae” in the sky and some of the other “faint fuzzies” seen through telescopes were actually separate galaxies or “island universes” from our own, astronomer Edwin Hubble sought to classify these objects. Origins of Galaxy Types & Classification Hubble’s Sequence of Galaxies For a list of our top 50 galaxies to observe, we have a separate article going into more detail with more curated objects for you.

The galaxies we’ve listed in each category are those that we’ve picked because they show the defining feature of their given morphological type many other well-known galaxies fit into each type we’ve listed. This article will give an overall layout of the classification and known types of galaxies, as well as some you can observe yourself with a fairly modest telescope under suburban or dark skies.

However, there are quite a few exotic types, some of which can be observed with backyard telescopes, and numerous intermediate classifications and variations between the most commonly described types. You may have heard of the classes of spiral, elliptical, and irregular galaxies, along with perhaps lenticular galaxies, too. There are many more types of galaxies than common thinking might suggest.

Parts of a barred spiral galaxy