Learning something for the first time.

action of observing carefully. Remarks or comments on some things you noticed.

Astronomy a diffuse cloud of particles and gases (mainly hydrogen) that is visible either as a hazypatch of light (either an emission or a reflection nebula) or an irregular dark region against a brighter background(dark nebula).

material thing. Goals or purposes of particular plans or activities. To disagree; to protest against an idea or plan.

likely or prone to be affected by. conditionally upon. People who take part in experiments or tests. To cause to suffer or experience something.

making interesting information known. To show something that was hidden before.

Concerning the orbital characteristics of a planet.

find unexpectedly or while searching.

Used to add new (often different) information.

characteristic of one person or thing, and so serving to distinguish it from others.

to moderate extent or by moderate amount.

To be left undone (after other things changed).

In a way that is easy to understand; obviously.

relating to action or process of closely observing or monitoring something or someone.

Thing, person which represents a category. be illustrated or exemplified.