Well i could be totally wrong but here goes. Look up into the night sky and what do you see? Trillions of stars.Burning brightly, lighting up the sky.Looks pretty. But that's about it. Stars die all the time, we barely think about it. However our Sun is also a star. But for every human on earth it's sooo much more than that. The sun provides life. Without it we'd have no food. No warmth. The ecosystems would crash. It means our life.We don't view it as an average star. It's something we would perish without.
So when it says "Every star is a sun to someone" it probably means something you take for granted, and don't necessarily place high importance on (like the stars at night) may be something essential,precious,needed in the eyes of someone else (like our sun). It carries the tone of "one man's trash is another man's treasure." It may not mean much to you or I, but it means something to someone else.
Social constructivism was developed by post-revolutionary Soviet psychologist Lev Vygotsky. Vygotsky was a cognitivist, but rejected the assumption made by cognitivists such as Piaget and Perry that it was possible to separate learning from its social context.