[General] Why does the author use an indefinite article instead of “the” before the word “sun”

[rodgers white]

The following sentence in italic type is selected from the book called “English Studies Series” written by William F. Hawkins:

Actually we know of no type of astronomical body in which the conditions can be favourable to life except planets like our own revolving round a sun.

My question is: Why does the author use an indefinite article instead of “the” before the word “sun”?


You can have a look at the following website for more information:
http://www.uefap.com/reading/exercise/ess3/jeans.htm

 

[jutfrank]

He's implying that there are many suns, of which ours is just one example.

For an astronomer, there are billions of suns.
For a non-astronomer, there is just one, so we tend to say the Sun.

 

[rodgers white]

He's implying that there are many suns, of which ours is just one example.

For an astronomer, there are billions of suns.
For a non-astronomer, there is just one, so we tend to say the Sun.

Thanks for your explantation. However, what really makes me feel confused about is: here the word "sun" obviously refers to the sun in our solar system (except planets like our own planet - the earth - revolving round the sun). So, again why?

 

[rodgers white]

It doesn't.

So, you mean I can say to my students such a sentence: Our earth is revolving round a sun.

 

[rodgers white]

You can. Our earth does revolve around a sun.

We normally refer to our sun as 'the sun', but we don't' have to. The person who wrote the original sentence was not referring to our sun.

Now, my puzzle is: When I say that both sentences are okay, how can I explain this clearly to them if my students ask why ?

Our earth revolves the sun.

Maybe I can explain like that: When we are standing in the space within the solar system, this sun is unique.
So, we call it "the sun".

Our earth revolves a sun.

When we are standing in the universe - there are many stars like the sun out there - and looking back at our home planet, we can say: Oh, look, our earth is revolving round a sun, and it's so beautiful!

 

[engee30]

Now, my puzzle is: When I say that both sentences are okay, how can I explain this clearly to them if my students ask why ?

In simple terms, I'd use the word exemplification, where you're not referring to a thing as we know it, but to a representative example of the particular thing -- whether it be existent or not.

 

[emsr2d2]

You can't use "Our earth revolves the sun" or "Our earth revolves a sun". There is a word missing after "revolves" in both.

 

[rodgers white]

You can't use "Our earth revolves the sun" or "Our earth revolves a sun". There is a word missing after "revolves" in both.

Thank you, emsr2d2. I am really sorry for my carelessness.

Our earth revolves round a sun.
Our earth revolves around the sun.

 

[bubbha]

Usually, "the sun" or "the Sun" refers to the star of our own solar system, while "a sun" refers to some unspecific star elsewhere in the universe. There are exceptions, of course, based on context. In science fiction stories that take place in other solar systems, beings living on a planet may refer to the star around which their planet revolves as "the sun".