They are just wonders of the sky.
Yes, galaxies can orbit around a central point, such as a supermassive black hole located at the center of a galaxy. This motion is influenced by the gravitational forces within the galaxy.
A cluster is a collection of galaxies, normally less than about 50 galaxies. All clusters are different and all galaxies are different. A ball point figure would put the maximum number of stars at around 10,000,000,000,000 stars or 10 trillion.
The galaxies themselves are not expanding, and they're not all retreating out from any central point. Every point in our Universe is moving away from every other point, because the entire fabric of space itself is expanding, taking the matter along with it. Thus, every observer at any point in our Universe observes all other galaxies moving away from the point where he happens to be located. No point can claim to be the "central" point. It was Edwin Hubble, working at Caltech and the Mt. Palomar observatory, who was able to compile the radial speeds of enough distant galaxies to demonstrate the general expansion in every direction.
Irregular Galaxies do not, such as the Small Magellanic Cloud
who discovered the galaxies who discovered the galaxies
Spiral galaxies, barred spiral galaxies, elliptical galaxies, and irregular galaxies
The possessive form for the plural noun galaxies is galaxies'.Example: Their galaxies' paths do not coordinate.
Elliptical galaxies are sometime called dwarf galaxies.
We don't actually know - because we cannot see the universe beyond a certain point due to the fact that we are in it. We have named the cluster of galaxies we are in the Virgo Cluster but there are many other clusters and lone galaxies as well. So we'll probably never know that answer!
15 Galaxies? There are over 1,000,000,000 galaxies possibly more.
no galaxies are not harmful
Yes, galaxies do orbit around a central point in the universe, which is typically a supermassive black hole located at the center of a galaxy. This motion is influenced by the gravitational forces within and between galaxies.