Our home-galaxy the Milky way is way bigger than it was previously thought.

Astronomers have had a major breakthrough in revealing the size of our galaxy.

How big is our Milky Way Galaxy?

Our Sun is located in the pancake-shaped disk of the star-cluster which is also the brightest region of the Milky Way Galaxy. It stretches some 120,000 light-years across.

The region beyond this massive stellar disk is an envelope of gas. Both stellar disk and the gas envelop is completely surrounded by a massive halo of dark matter, most probably filled with invisible energy particles. Due to this complexity, it’s difficult to measure its radius.

But Alis Deason and her team at Durham University in England used the positioning of our neighboring galaxies to identify the Milky Way’s edge.

According to their research published at arxiv.org on 21st February, our galaxy has a diameter of 1.9 million light-years or it is 950,000 light-years from one edge to the Milky Way’s Center.

Milky way galaxy
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Image credit: NASA


To unravel the secret of the Milky Way Galaxy’s size, astrophysicist Deason with her team managed to build the computer simulations of the birth of the giant galaxies.

They precisely searched for cases of 2 massive galaxies rising next to each other to study how an individual galaxy’s gravity pulls on the other. For example, the Milky Way galaxy and the Andromeda galaxy pulling their counterparts towards each other.

These simulations revealed that the velocities of small neighboring galaxies dropped drastically just after the dark halo’s edge of a giant galaxy.

This finding was double confirmed by the team using the existing telescope observations as they noticed the same drop in the velocities of small galaxies near our Milky Way galaxy.


Also read: Supermassive Black Hole Explosion is the Biggest Ever Recorded


Even though most of the Milky Way’s mass is made of dark matter, the study shows that there are stars existing at those far-out distances.

“Both have a well-defined edge. The edge of the stars is very sharp, almost like the stars just stop at a particular radius”, Alis Deason said in an interview.

This discovery intensifies the possibility of mapping the galaxies more accurately and precisely in the future.

The scientists can pinpoint the exact location of galaxies by accurately studying the positioning of the nearby small galaxies and could also locate individual stars at the border of the galaxies. Our galaxy still has an infinite number of secrets held within, the curiosity of humans to know more is one of the key factors to unravel them. 


Chetan Raj

I'm a writer, entrepreneur, and traveler obsessed with technology, travel, science, and the world we are living in. I realized the value of 'true knowledge' for the 1st time in my graduation which is one of the many reasons to create this magnificent platform...

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