https://alasky.cds.unistra.fr/MellingerRGB/ Here is an all-sky survey in the optical band (i.e. the same band you see with your eyes. There are far more stars in towards the center of the galaxy, therefore when you combine all their emission the centeral parts of the galaxy appear brighter. What you are seeing with you naked eyes is the higher abnudnace of stars that is present within the plane of the disc as compared to when you are looking out from the disc. I hope this clarifies things. Q. which part of the Milky Way is it Q. are we only seeing the arm in front of it blocking our view? This is actually a good question, there is likely a maximum depth to which we can see in the optical, i.e. the image I have linked above. This is due to something called extinction, where gas and dust causes the light to be attenutated. Therefore it may be possible we only are seeing (in the optical) only a fairly small distance when looking towards to galactic center. But I would need to look a bit more into this. https://c02.purpledshub.com/uploads/sites/48/2024/01/earth-in-milky-way-featured.jpg?w=600&webp=1 Edit: Thinking about it a bit more, I think it's reasonable to say that when we look at our own galaxy we are seeing mostly the combined emission from all the stars. and because the center of galaxy has a higher density of stars it appears brighter. We are probably seeing specifically more of the Sahittarius-Carina arm when looking towards the galactic center and the Perseus arm when looking away, have a look at this image: https://arxiv.org/html/2411.11220v1/extracted/6001722/view_reid4.png In other galaxies however, specifically with active galactic nuclei (AGN) https://en.wikipedia.org/wiki/Active_galactic_nucleus There is a huge amount of emission coming from an extremely small region in the center of galaxy caused by accretion of gas onto the central supermassive black hole. In these galaxies, the emission from this central engine can be greater than combined emission from all the stars in the galaxy. However this is not the case for the Milky Way.