Linda Bo is the pioneer of spiral arm formation……
Origin of the name
The name of the spiral galaxy free bulge outward logarithmic spiral in the galactic disk extension, and a bright spiral arm star formation. Although it is sometimes difficult to identify, such as spiral arm clusters of flock knot, but the spiral arm relative to distinguish the galactic disk structure, but without the lens of the spiral arm galaxies.
The galactic disk of spiral galaxies usually have a large spherical galaxy halo surrounded by one of the main members of the old second star family star, there are many gathered in the globular clusters around the galactic nucleus.
Linda Bo is the pioneer of spiral arm formation, he realized the star to be permanent to keep the snails.The shape of the spiral arms will encounter the “winding dilemma” and difficult to sustain, because the arm of the galaxy disk objects around the speed varies with the distance to the center, a radiating outward (like the spokes of the wheel ) soon because the galaxy since the turn into the arc. Galaxy as long as the rotation a few weeks after, the curvature of the spiral arms will increase to a tightly wrapped around the galaxy bulge. Observed is not the case. First an acceptable theory is invented by the Lin family of Alice and Frank H. Shu, two in 1964, they suggested that the spiral arms only show the spiral density wave. They assume that the stars in the elliptical orbit of the slender and the original track direction inter-related, that is, the ellipse to a very smooth way with the increase in core distance gradually changing their direction. This is described in the figure, clearly observed in elliptical orbits in certain areas closely linked to the “phenomenon” is a spiral arm. The star is not always maintain the position that we see now, they just move through the spiral arm in orbit.
Two optional one another has been recommended by the hypothesis of galaxies caused by the movement of the star into a wave, because the formation of the brightest stars will be the fastest death will be a dark area behind the wave, thus making the waves seen.