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e_j_white t1_j4kcf6n wrote

Great answers here, just want to add that we don't "know" for sure. We're still trying to measure the size of Milky Way every year.

We thought it was 100K ly across, but some researchers in 2015 claimed it's 150K ly.

Just recently, a new publication is now saying it could be 200K ly across!

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jeweliegb t1_j4kqde3 wrote

It better not be! It'll render Monty Python's Galaxy Song completely wrong and that's the only way I remember any of those space-related numbers.

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VoilaVoilaWashington t1_j4law8c wrote

> We thought it was 100K ly across, but some researchers in 2015 claimed it's 150K ly.

Just for clarity, this doesn't mean that the measured outer edge is actually that much farther away, but rather that we're finding things farther away.

It's a bit like saying a city is 10km across, but then realizing that there are actually buildings outside that radius. You didn't measure the original wrong, you simply expanded the definition.

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Crowasaur t1_j4kuf6z wrote

Not to mention the expanding Fermi-bubbles out of the core and the remnants of past absorbed galaxies orbiting in, around and through us in long strings

The Milky way looks more like "Deep Space Nine" than a bulging disk.

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kcalb33 t1_j4mjsz6 wrote

I read an article today saying there are milky way stars half way towards andromeda

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Oknight t1_j4mon6h wrote

But remember the size isn't really a determined thing... the galaxy doesn't have "start and end" points it's a vague cloud mostly of surrounding dark matter in a gigantic halo. There's a "center" to the spiral structure of the areas that are most actively forming stars and where gas and dust are densest but that isn't a strongly defined point the way the Sun is for the Solar System.

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