Galaxies and Their Sizes
Part of Scales of the Universe.

We live in the Milky Way Galaxy, a disk-shaped galaxy roughly a hundred thousand light-years across and two thousand light-years thick. The smallest dwarf galaxies are a few percent of that size. The largest galaxies, found at the centers of galaxy clusters, are more than ten times larger than the Milky Way.
If the Hayden Sphere is the size of the Local Group of galaxies, then this model is the relative size of the Milky Way Galaxy
Our Milky Way Galaxy contains more than a hundred billion stars. Along with Andromeda and Messier 33, it is one of three large members of our Local Group of galaxies.
AMNH/D. Finnin
AMNH/D. Finnin
AMNH/D. Finnin
AMNH/D. Finnin
If the Hayden Sphere is the size of the Milky Way Galaxy, then this model is the relative size of the globular star cluster Messier 80.
The globular cluster Messier 80 is a collection of tens of thousands of stars, bound together by their mutual gravity. The Milky Way Galaxy contains about two hundred globular clusters.
AMNH/D. Finnin
If the Hayden Sphere is the size of the globular star cluster Messier 80, then this model is the relative size of the Oort Cloud of comets.
The Oort Cloud is a spherical swarm of trillions of comets orbiting the Sun. It extends about a fifth of the way to the nearest stars.
AMNH/D. Finnin
If the Hayden Sphere is the size of the Oort Cloud of comets, then this model is the relative size of the Kuiper Belt of comets.
Named after the astronomer Gerard Kuiper, this broad disk of millions of comets orbits the Sun beyond the planet Neptune. The Oort Cloud of comets is five hundred times larger.
AMNH/D. Finnin
If the Hayden Sphere is the size of the Kuiper Belt of comets, then this model is the relative size of blue supergiant star Rigel.
Rigel is a blue supergiant star marking the knee of the constellation Orion. If placed where the Sun is, Rigel would engulf the orbit of Mercury, the innermost planet.
AMNH/D. Finnin
AMNH/D. Finnin
In This Section
Exhibit
Milky Way Galaxy
If the Hayden Sphere is the size of the Local Group of galaxies, this model is the relative size of the Milky Way Galaxy.
Exhibit
Messier 87
If the Hayden Sphere is the size of the Local Group of galaxies, then this model is the relative size of Messier 87.
Exhibit
Messier 101
If the Hayden Sphere is the size of the Local Group of galaxies, then this model is the relative size of Messier 101.
Exhibit
NGC 1365
If the Hayden Sphere is the size of the Local Group of galaxies, then this model is the relative size of NGC 1365.
Exhibit
Messier 80
If the Hayden Sphere is the size of the Milky Way Galaxy, this model is the relative size of star cluster Messier 80.
Exhibit
Oort Cloud
If the Hayden Sphere is the size of the star cluster Messier 80, this model is the relative size of the Oort Cloud of comets.
Exhibit
Kuiper Belt
If the Hayden Sphere is the size of the Oort Cloud of comets, this model is the relative size of the Kuiper Belt of comets.
Exhibit
Rigel
If the Hayden Sphere is the size of the Kuiper Belt of comets, this model is the relative size of blue supergiant star Rigel.