Last night,I and my brother suddenly saw that some(50-60) dots of light( exactly like stars) were moving through a straight line(from NW to SE) above us with same velocity and towards exactly same directions.These moving stars were seen for just a few seconds.Then they didn't disappear, they just crossed us. We became confused. My brother is highly interested in astronomy. But he was unable to detect the phenomenon. I think this case is rare. What may they be?
That was likely the latest StarLink satellite constellation.
Note that usually it is important to give an exact time and place to answer questions like this, but in this case the answer looks fairly obvious. It really does look odd to see the constellation fly overhead (later it will disperse into separate orbits and not be very conspicuous).