The Norma Arm is a minor spiral arm of the
Milky Way extending from and around its central hub region.
The inner portion of the Arm is called the ''Norma Arm'' in narrow meaning. The outer part of it is identified either with the Cygnus Arm, which lies outside the
Perseus Arm, or the Outer Arm, which is located farther away from the center of the Galaxy than the Cygnus Arm.
[ The Norma Arm begins from the Galactic Center,]star
A star is an astronomical object comprising a luminous spheroid of plasma (physics), plasma held together by its gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked ...
s shaped into the form of a relatively flat disc by gravity. The disc is rotating, with the dense central body of stars moving at greater speeds than those toward the rim of the disc. As a result, the pattern of stars within the Galaxy as viewed from directly above or below the disc has formed into a spiral.
Because of localised gravitational variations, the spiral pattern has itself formed several distinct 'spiral arms', where particularly large numbers of stars can be found.[
]
See also
* Galactic disc
References
{{Portal bar, Stars, Spaceflight, Outer space, Solar System
Milky Way arms
Galactic astronomy
Spiral galaxies