Until a century ago, astronomers were so fascinated by our Milky Way galaxy that they thought it is the only galaxy from the Universe. An American astronomer changed that perception forever – Edwin Hubble discovered in 1925 that there are many other galaxies out there in the tremendous vastness of our reality.
Even though the astronomers’ view about the Milky Way galaxy changed drastically since Hubble’s discovery, our stellar neighborhood is still a very exciting region to explore.
1.9 million light-years in diameter
A team of researchers from Durham University in England has found the edge of the Milky Way galaxy. Astrophysicist Alis Deason along with her colleagues has determined the diameter of the Milky Way: 1.9 million light-years (having a margin of error of 0.4 million light-years). They had been using nearby galaxies as a guide.
In the study paper, the researchers wrote:
In many analyses of the Milky Way halo, its outer boundary is a fundamental constraint,
Often, the choice is subjective, but as we have argued, it is preferable to define a physically and/or observationally motivated outer edge. Here we have linked the boundary of the underlying dark matter distribution to the observable stellar halo and the dwarf galaxy population.
The Milky Way galaxy is estimated to have from 100 billion to 400 billion stars, and also over 100 billion planets. Our Solar System is located at a distance of about 27,000 light-years away from the Galactic Center, more precisely on the inner edge of the Orion Arm. We can see a part of the Galactic Center at the night sky, and we can consider ourselves lucky that something or someone positioned our planet far from it.
If our Earth would have been in the Galactic Center of the Milky Way, it wasn’t possible for life to develop as we know it. Therefore, we should be thankful to the Milky Way for allowing us to exist and admire its beauty.