The universe is filled with galaxies, including our own Milky Way.

When pictured, galaxies appear like fairly set areas with clear beginnings and endings.

The reality, however, is not nearly as obviously.

According to a paper that was published in the journal Nature Astronomy, a team of scientists suggests that the boundaries between galaxies in interstellar space should be refined.

With this definition, the outer boundary of the Milky Way would go out much further than previously understood.

In fact, the furthest ends of the galaxy would reach all the way to the Andromeda galaxy, which is our nearest galactic neighbor.

While the area does not have massive stars or planets, it is also not empty space. The area has large bubbles of gasses that are only recently being researched. The gasses exist in the circumgalactic medium (CGM) and surrounds galaxies.

Astronomers have long known that the Milky Way and the Andromeda galaxy were drifting toward each other and would eventually collide. Of course, it was estimated that this would not occur for another four billion years or so.

Nikole Nielsen , an associate professor at Swinburn University, said in a statement:

“It’s highly likely that the CGMs of our own Milky Way and Andromeda are already overlapping and interacting.” He went on, “We’re now seeing where the galaxy’s influence stops, the transition where it becomes part of more of what’s surrounding the galaxy, and, eventually, where it joins the wider cosmic web and other galaxies. But in this case, we seem to have found a fairly clear boundary in this galaxy between its interstellar medium and its circumgalactic medium.”

While this will have little practical implications for our two galaxies, it does provide additional information to researchers.

This will help us to better understand how galaxies are formed, changed, and evolve over time. Nielsen said:

“The circumgalactic medium plays a huge role in that cycling of that gas. So, being able to understand what the CGM looks like around galaxies of different types — ones that are star-forming, those that are no longer star-forming, and those that are transitioning between the two — we can observe [how] changes in this reservoir may actually be driving the changes in the galaxy itself.”

As technology evolves astronomers will likely be able to look at the CGM of other more distant galaxies and learn more about them as well.

The colliding of galaxies sounds terrifying.

If you thought that was interesting, you might like to read about a second giant hole has opened up on the sun’s surface. Here’s what it means.