When Did this happen entirely in the early universe or is it

When: Did this happen entirely in the early universe or is it still going on (may be different for different types of galaxies)? Similar in Stars: Do we see a similar process happening in star formation? Spirals and Ellipticals: How is this process different in spiral and elliptical galaxies?

Solution

.Collapse:Sooner or later a radical shift in the force of the universe will cause every little particle in it become extremly heavy.The new weight will squueze all materials into small super heavy ball and the universe will cease to exist.The risk of collapse is even greater than previous.

.Higher mass stars will switch from helium to carbon burning and extend their life time .

.Spiral galaxys are stable against gravitational collapse

.Elliptical rotational speed is relatively small.It is preventing the stars from being pulled toward center.

Spin:

.Individual galaxys ,collection of some mind boggling number of atoms that spin.

. Star spin rate depend on its age because it slow down steadily with time .Star spin also depend on mass.

.Spinnig spiral is an example of motion after effect optical illusion.

.Group of stars in ellipticals donot rotate.

Star formation:

.Star formation are all concentrated in the disk of galaxy

COLLISION:

.It is predicted to occur in about 4 billion years.

.In stars there will be no collision.Even If it happens it occurs for somemillion years.

.Spiral galaxys will merge to form an elliptical galaxy.Galaxys that collide with one another will take millions of years to merge.

.Elliptical galaxys merge with spiral galaxys.Most galaxys donot collide.