A brief sight of something. To see or notice something very briefly.

expert in or student of astronomy. Scientist studying stars and other bodies in space.

sentence worded or expressed so as to elicit information. Issues or problems you are dealing with. To have or express concerns or uncertainty.

likely or prone to be affected by. conditionally upon. What a book, article etc. is about; theme. cause or force person or thing to undergo.

Used to add new (often different) information.

small, narrow river. Classes split into ability levels. run or flow in continuous current in specified direction.

way in which one acts or conducts oneself.

person who watches or notices. People whose job it is to watch or notice things.

All of space that contains planets and stars.

positioned in or relating to sky, or outer space as observed in astronomy.

of very distant past. old man.

undergoing natural development by increasing in size and changing physically. Act of cultivating plants for food. To improve; to develop better skills over time.

To have a thought/feeling without expressing it.

document giving authorization. Pieces of paper giving you rights to do some things. allow to do something.

celestial body moving round star. One of the bodies that orbit the sun.