: Why are other planets and stars and all that colourful galaxy not visible in the sky the same way we see the moon and sun in our everyday mundane lives with naked eyes?
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The galaxy *is* visible in the sky. In a very dark sky at midsummer, it appears as a band of light that stretches all the way across the sky from one side of the horizon to the other. In fact, the word *galaxy* comes from the Greek word for *milky* because the Greeks thought it looked like milk (specifically, in Greek myth, the goddess Hera’s breastmilk) strewn across the sky. It’s etymologically related to the modern English words “lactate” (to produce milk) or “lactose” (a sugar found in milk): the *lac* in those words and the *lax* in “galaxy” are the same root. And of course, we still call our galaxy the “Milky Way” for this appearance.
Some stars are, of course, also visible. You see them every night, even in a light-polluted sky.
The reason they don’t look like the Moon or the Sun is that the Moon and Sun are very close to us. They’re big enough for us to make out details. But other stars and planets outside of our Solar System are *extremely* far away, too far away for your eye to discern any detail. Your eyes don’t quite have a “resolution” in the same way that a TV screen does, but they kinda-sorta do (more specifically, they have a minimum size they can *resolve*), and you might say that stars in the sky take up much less than a “pixel” of your vision.
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