Astronomy breakthrough: discovering the edge of Our Galaxy



One can always be overwhelmed by the vast size of our galaxy even without knowing how large it actually is. However, with the help of new technologies, astronomers have been diving deep into our galaxy’s mysteries. Thus, they have now discovered that the Milky Way is even bigger than we’ve imagined, via locating its edge.

A massive galaxy

Officials in New York have announced that the Milky Way stretches for almost 2 million light-years across. Thus, it is 15 times wider than its already enormous luminous spiral disk. The new data will scientists in estimating the sheer size of galaxies, as well as the many other galaxies orbiting around it. It will also “help astronomers tease out other galactic properties,” said Rosemary Wyse, an astronomer at Johns Hopkins University.

For now, scientists believe that there are 60 known galaxies orbiting the Milky Way. However, this new data will help unveil more of them, along with their fascinating mysteries.

The Edge

“In many analyses of the Milky Way halo, its outer boundary is a fundamental constraint,” the researchers write in their paper. “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.”

In the Milky way, there is a pancake-shaped disk of stars that houses the sun, which is 120,000 light-years across. Moreover, beyond that disk, there appears to be a disk of gas. However, what both disks have in common is a vast halo of dark matter. It engulfed both, while also stretching way more. Furthermore, the dark matter allows stars to exist within even further away from distance from both disks. If only for a certain point.

“Both have a well-defined edge,” Deason says, an astrophysicist at Durham University in England. “The edge of the stars is very sharp, almost like the stars just stop at a particular radius.” Hence, at the end of the stars, is where our galaxy ends.

Dark matter

The dark matter is equivalent to everything we see in the universe. This matter doesn’t only absorbs and reflects, but it also emits and interacts with electromagnetic spectrums like radio waves, visible light waves, or x-rays.

For a long, scientists ignored the importance of dark matter. This changed in the 1970s when experts started realizing its potential and significance.

Future discoveries

Locating the edge of the galaxy will play a significant role in future space discoveries. It will not only help in discovering new small galaxies nearby, but it will also help in identifying the individual stars out at the boundary. The measurement will also help in organizing future experiments as well as solving some of the space’s mysteries. Moreover, the paper states that “There is great hope that future data will provide a more robust and accurate measurement of the edge of the Milky Way and nearby Milky Way-mass galaxies than the one we have presented here.”


A.M, A. M. W. (2020). Astronomers have finally found the edge of the Milky Way galaxy. BER. https://bgr.com/2020/03/30/milky-way-galaxy-astronomers-have-found-the-farthest-edge/Looking for the edge of the Galaxy | Spaceaustralia. (2020). Space Au. https://spaceaustralia.com/feature/looking-edge-galaxyStarr, M. (2020). Astronomers Think They Just Found The Edge of The Milky Way Galaxy. ScienceAlert. https://www.sciencealert.com/astronomers-have-found-the-edge-of-our-galaxy-it-s-bigger-than-you-thinkThompson, H. (2020, March 23). Astronomers have found the edge of the Milky Way at last. Science News. https://www.sciencenews.org/article/astronomers-have-found-edge-milky-way-size


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