100,000 light years refers to...
• the size of the spirals with or galaxy (Milky Way)
• an approximate measure of the luminosity of the galaxy
• an approximate measure of the distance across the galaxy****
agree (but Googled :)
https://www.google.com/search?q=size+of+milky+way+galaxy+in+light+years&ie=utf-8&oe=utf-8
100,000 light years refers to an approximate measure of the distance across the galaxy. To understand this, we need to first understand what a light year is.
A light year is a measurement of distance, not time. It represents the distance that light travels in one year, which is approximately 9.461 trillion kilometers (5.878 trillion miles). Since light is the fastest thing in the universe, it is commonly used to measure vast distances in space.
In this case, 100,000 light years refers to the distance across our galaxy, the Milky Way. The Milky Way is a barred spiral galaxy, and its diameter is estimated to be about 100,000 light years. So if you were to travel across the Milky Way from one end to the other, it would take approximately 100,000 years traveling at the speed of light.
It's important to note that this is an approximate measurement as the exact size of the galaxy is still a subject of scientific research and ongoing study.