You have undoubtedly heard the name “Milky Way.”
It is the galaxy we live in, after all, but a universe not so far away, known as Andromeda, is just as fascinating as it!
Though it’s 2.5 million light-years away, the Andromeda galaxy has a lot to show us about itself and even the Milky Way.
A new study published in The Astrophysical Journal from NASA scientists speaks about a “halo” around Andromeda.
The halo, which appears a lot like a vast plasma bloom, spans 1.3 million light-years into space.
That is approximately halfway to our galaxy, which is fantastic!
When we think of a galaxy, we often see them as self-contained collections of planets, stars, and gasses, but it’s usually not the case, as there’s a lot more to a galaxy than just that.
The effects of a galaxy go far beyond their outer edge
It turns out that the line between the edge of a galaxy, and space is so thin that there’s hardly a real “edge” at all.
In Andromeda’s case, the plasma halo is so massive that the galaxy looks like a dwarf by comparison.
Samantha Berek from Yale University, the co-author of the research, said that understanding the great gaseous halos surrounding galaxies is extremely important.
“This reservoir of gas contains fuel for future star formation within the galaxy and outflows from events such as supernovae. It’s full of clues regarding the past and future evolution of the galaxy, and we’re finally able to study it in great detail in our closest galactic neighbor,” she said.
Detecting The Halo
To detect the halo, NASA scientists observed the light of quasars located farther away than the galaxy.
Then, they measured the light of the quasars in contrast to Andromeda’s proximity, from our earthly point of view.
The thicker a plasma halo is, the more light from a quasar gets absorbed before it passes on to reach Earth, providing a series of new data points – 43 to be precise.