Actual number of stars in the Milky Way

[Stickman76]

I hear wild varying estimates of how many stars there are in the Milky Way Galaxy, from 200 billion to 400 billion. Is the number closer to 200 billion or closer to 400 billion? What methods are being employed (other than GAIA) in order to count them?

 

[rootone]

What methods are being employed?

https://www.jwst.nasa.gov/
While it's not the only one, it's a pretty big deal

 

[Stickman76]

rootone, thank you! I am familiar with JWST as well. Can't wait for it to get into space and start doing science. Do you know how the number of stars has been estimated to date? And why the large discrepancy between estimates I mentioned in my OP? Thanks!

 

[Vanadium 50]

About 85% of the Milky Way is invisible to us because of dust (and to a lesser extent, geometry). Most stars are red dwarfs, which are extremely dim. Combine the two, and it's hard to count what you don't see.

 

[snorkack]

About 85% of the Milky Way is invisible to us because of dust (and to a lesser extent, geometry). Most stars are red dwarfs, which are extremely dim. Combine the two, and it's hard to count what you don't see.

Especially because the invisible part is qualitatively different. We may assume that the ratio of red dwarfs to bright stars is the same on the far side of Milky Way disc as it is on the near side, but most of the stars are in the inner Milky Way, which is also hid, and we have no reason to assume the ratio of red dwarfs to bright stars should be the same there.

 

[Stickman76]

Snorkak, thank you for the additional input. So then it seems as though our estimates of how many stars there are in the galaxy is based on a survey of a given observable area of the galaxy and an approximation of the stars in that area that is then multiplied by the known estimated size of the galaxy, or similar technique. I suppose the estimation takes into account that there are more stars toward the center and fewer toward the outer edges, however it seems as though there is a large discrepancy between the high and low estimates. 200 billion - 400 billion is a 100% increase. This is a hard problem as are many in astronomy, however I am pursuing a career in said field and am very curious about the Cosmos so I will continue to ask questions. Thanks again to all who have chimed in on this topic.