The Milky Way is broken up into five different arms; the Perseus Arm, the Carina-Sagittarius Arm, the Norma Arm, the Crux Scutum Arm, and the Outer Arm. The way in which our universe spirals is similar to the spiral of hurricanes, nautilus shells, and bracts on a pinecone. Other galaxies have formed in the same way including the Andromeda Galaxy, the Barred Spiral Galaxy, and the Pinwheel Galaxy. The galaxies simply differ in their “tightness” of arms but all resemble the Fibonacci sequence. The Fibonacci spiral comes from manipulating the sequence 1, 1, 2, 3, 5, 8…and so forth.

The recursive sequence follows the rule that each pair of numbers adds up to the next in the sequence. While the sequence does not converge because it tends to infinity, dividing each number within the sequence by its preceeding creates a series which tends to tends to the limit of the Greek symbol Φ.  or approximately 1.618034. Using  Φ, pronounced Phi, and applying it to the length of an arc of rotation, each arm within a universe pans out from the center at an angle of 137.5 degrees after each quarter turn. The same spiral is seen in the way leaves spiral up stems to not lay on top of each other or in the formation of ancient architecture.

Some spiraling galaxies have mutual attraction due to their gravitational pull. It has been theorized that the Milky Way and its neighboring universe, Andromeda, will merge into one consistent spiral within the next 4 billion years.

To read more on spiraling galaxies click here.

To read more on the golden ratio within the Milky Way click here.