Astronomers have found the edge of the Milky Way at last; Our galaxy spans 1.9 million light-years, a new study finds (satellites, dwarf)

[Michael Way]

''Our galaxy is a whole lot bigger than it looks. New work finds that the Milky Way stretches nearly 2 million light-years across, more than 15 times wider than its luminous spiral disk. The number could lead to a better estimate of how massive the galaxy is and how many other galaxies orbit it.''

https://www.sciencenews.org/article/...milky-way-size

[rjshae]

The Milky Way doesn't have a sharp border. It may stretch even further in some directions.

[Milky Way Resident]

Pretty interesting find. The galaxy itself is still between 100k-120k light years, if we are talking about the main disc .

[BigCityDreamer]

So, is this article suggesting that the dozens of dwarf galaxies that orbit the Milky Way galaxy within that 2 million light years are actually a part of the Milky Way galaxy?

[rjshae]

They'd be considered satellites, kind of like globular clusters. In astronomy, the border of a system is usually defined by its sphere of gravitational influence -- the Hill sphere -- where orbiting objects are not easily dislodged by an outside force.

[Milky Way Resident]

Originally Posted by BigCityDreamer

So, is this article suggesting that the dozens of dwarf galaxies that orbit the Milky Way galaxy within that 2 million light years are actually a part of the Milky Way galaxy?

As of right now they are satellites. The Milky Way and Andromeda are the two behemoths of the Local Group. Most of the other galaxies part of the group, orbit one of them, though there’s some debate on whether some of the furthest members are actually bound to either galaxy. In the far future, it is expected that all of these galaxies will merge into a giant elliptical.