No, it shouldn't all be uppercase, and it doesn't need to be capitalized unless it is the first word in a sentence or part of a title.
ἀστρονομία
No.
A Yagi antenna, which can be used for radio astronomy.
When it is at the start of a sentence.
Cosmonaut is the Russian word for astronaut.
The first letter of the word should be Uppercase and that's it.
Enter the Uppercase character of the word "capTain"
Enter the Uppercase character of the word "capTain"
Astronomy is a long word.
No.
The correct spelling is indeed this: WikiAnswers - one word; no hyphen' uppercase "W" and uppercase "A."
My brother is studying astronomy.
No, the noun astronomy is an uncountable noun, a word that can't be separated into countable parts. The word astronomy is an abstract noun for a concept.
I want to study astronomy later on in life.
The word 'astronomy' is a noun, a word for the science that deals with the universe beyond the Earth.
I like the study of Astronomy. Of course.
as·tron·o·myThus, there are4 4 syllables in astronomy.4 syllables.