For all we know, it’s expanding indefinitely into limitless bounds. We know this by studying red-shift.
Each galaxy forms stars, planets and other solar remnant. On the grand scale of things, the Milky Way galaxy where we reside is tiny in comparison.
Universe expansion is the theory that galaxies and all matter in space are increasing in distance between each other. But the true extent of outer space is still unknown. It’s mind-boggling what could be out there.
The Farthest Viewable Galaxy
This surprisingly bright infant galaxy, named GN-z11, is seen as it was 13.4 billion years in the past. In other words, it’s the oldest, most distant galaxy in the observable universe.
If you look at the origin of the Big Bang, it’s just 400 million years after it. This galaxy has a high red-shift, meaning that this galaxy is moving away in distance.
Astronomers also use the NASA Spitzer Space Telescope to greatly improve the cosmic distance ladder used to measure the expansion rate of the universe, its size and age.