If yes, why then aren't we able to see the whole galaxy. At a such a large distance shouldn't the whole galaxy be seen as one?
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No, stars in other galaxies are too far away to be distinguished with the naked eye. But in good viewing conditions, the galaxy in Andromeda is barely visible as a faint smudge.
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The individual stars in other galaxies, or even in the more distant regions of our own galaxy, appear too faint and too apparently close together to see singly, so we just see them as a spread-out glow if at all. The exception is if there is a supernova in a galaxy very close to our own, since a supernova can easily outshine its entire host galaxy.
However you can see a star "from" another galaxy if that galaxy has since been absorbed into the Milky Way, forming what's called a stellar stream. One probable such star is Arcturus, among the brightest in the night sky.
However you can see a star "from" another galaxy if that galaxy has since been absorbed into the Milky Way, forming what's called a stellar stream. One probable such star is Arcturus, among the brightest in the night sky.
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Your eyeballs are too tiny. If you had eyeballs the size of trashcan lids you could see stars from other galaxies.
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SN 1987A was visible to the naked eye, in the LMC. I'm not sure what you are asking in your follow-up questions.