Galaxies and Their Sizes

Part of Scales of the Universe.

Galaxies and their sizes_HERO AMNH/D. Finnin

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.

Scales of the Universe: 10(20) Meters
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.
Milky Way galaxy
AMNH/D. Finnin
Messier-87
AMNH/D. Finnin
Messier-101
AMNH/D. Finnin
NGC-1365
AMNH/D. Finnin
Scales of the Universe: 10(19) Meters
Scales of the Universe: 10(18) Meters
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.
Model of globular star cluster Messier 80 on the Museum's Scales of the Universe path
AMNH/D. Finnin
Scales of the Universe: 10(17) Meters
Scales of the Universe: 10(16) Meters
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.
Oort cloud
AMNH/D. Finnin
Scales of the Universe: 10(15) Meters
Scales of the Universe: 10(14) Meters
Scales of the Universe: 10(13) Meters
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.
Kuiper belt
AMNH/D. Finnin
Scales of the Universe: 10(12) Meters
Scales of the Universe: 10(11) Meters
Scales of the Universe: 10(10) Meters
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
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

In This Section

Exhibit Milky Way Galaxy 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. 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, then this model is the relative size of the globular star cluster Messier... Exhibit Oort Cloud 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... Exhibit Kuiper Belt 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. Exhibit Rigel 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.