That depends a lot on how you define "live". For example:
* When will it stop having a spiral shape,
* When will it have so few stars that it can no longer be considered a galaxy,
* When will the last star have died out.
Depending on the intended meaning, you get quite different answers.
A so-called "great wall", which is a block of galaxies more than a billion light-years long.
it is 1 mile long
The vast distances involved means that the light we see left those galaxies a long time ago.
The vast distances involved means that the light we see left those galaxies a long time ago.
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.
Galaxies began forming around 13.6 billion years ago, not long after the Big Bang that created the universe. Over time, gravity caused matter to clump together, eventually forming the galaxies we observe today.
15 Galaxies? There are over 1,000,000,000 galaxies possibly more.
Not by a long shot. There are a few different possible outcomes, but if the galaxies remain together if anything the black hole you end up with is bigger.
no galaxies are not harmful