Well, Baba Yetu comes to mind... it's actually the theme song for the video game Civilization V, but the lyrics are a Swahili translation of The Lord's Prayer. It has a very lively, yet epic and solemn feel to it, which might fit pretty well. The sudden waves of new voices throughout the song also help symbolize the appearance of new life. (This piece was actually suggested last year in The Lion's Call forum reading group discussion of The Magician's Nephew.)

The Dawn from on High by Dan Forrest also reminds me of the stars singing, besides the fact that the title is also quite appropriate to this scene...

To me it always sounded more like that soprano, Lothlórien-ish song, but I really like the idea that @Cleander brought up of Baba Yetu, because it's such a joyful sweeping song that I could really see creation happening to it:

Think of this: The creation of life is God's ultimate physical expression of His creativity– that moment of creation, from the rising of the mountains to the first seeds bursting forth is an intensely emotional picture. I have great hope for this scene.

Oooh gosh, I've always thought, ever since I first read The Magician's Nephew (at the age of 7!!) and was absolutely blown away by the creation scene — "Wow, that would be THE most AWESOME scene for a film, but it would be almost impossible to do it any kind of justice!!!"  

I hadn't heard Now We Are Free or Baba Yetu before — great music, but to me a bit too tuneful for Aslan's creation song, which, as @Rose has reminded us, had "no words" and "hardly even a tune". Also a bit too much percussion, not that I mind that normally! It just sounds a bit too "human" to me, if you like, not otherworldly as I imagine Aslan's song to be.

The Dawn From On High I also hadn't heard before and have just been listening to bits of it (I don't have time right now for the full 40 minutes)... woah, now THAT is absolutely amazing (thanks, @Cleander!). Still maybe not quite what I would imagine for Aslan, but definitely something very, very special.

I honestly can't quite fathom how a composer (not to mention the film-makers) could really capture this whole incredible scene when it finally gets made — well, let's hope it does — but it'll be exciting to find out...

I think the trick will be to make it sound unique. High sopranos singing choral music absolutely makes sense for the stars, but it's also pretty standard for fantasy soundtracks. That being said, having Aslan be the main voice would definitely make it sound different. I'm thinking something like an acapella version of some of Bear McReary's choral bits in the Outlander soundtrack but with a very low bass like Patrick Page as the lead. His songs from Hadestown are not what I think it should sound like, but are an excellent example of just how low his voice can get.

If there is orchestration, I would like if they use some instruments that are not typically heard in symphonies. Instruments like the erhu and hurdy-gurdy are not utilized very often and would make it stand out.

I actually have a thread about Ideas for the score in Narnia films or series.

The stars should sound like angels, like high soprano singers. There even could be some mezzo-soprano stars as well. As a mezzo-soprano myself, it would be something to hear high soprano and mezzo soprano stars.

I think Aslan could have like the main melody and the stars sing the chorus like angels. I think both high sopranos and mezzo-sopranos could sound angelic!

I think they could very easily go down the route of showing a stunning visual montage of the universe being created, set to an awe inspiring orchestral soundtrack with operatic singers... if only because it's been done countless times before.

Terrance Malick's "The Tree of Life" is one that springs to mind most readily, but I'm fairly certain Darren Aronofsky did a similar sequence in both "The Fountain" and "Noah"

Therefore I think if you really want to wow audiences, you have to do something a bit more daring and unique.

I'm reminded in some ways of the penultimate song from the movie "Coda" where the girl starts singing, but then it cuts to a POV shot of her deaf mother. The movie then has several minutes of perfect silence, but you experience the song from the deaf mother's point of view - just seeing the looks of delight and wonder on everyone else's faces. In a way, it makes the song in your head more magical and special than anything she could have sung for real, to experience it that way.

I know that's an example of something that is highly specific to the particular circumstances of having a deaf mother, but I just cite it as a really interesting way to do something a little bit different and more inventive with the cinematic medium.

Sticking with Terrance Malick movies though, I really like the way this piece by James Horner from The New World slowly builds up from the sounds of nature layer-by-layer into something more grand and sweeping

To be honest, when it comes to movies with stunning visuals of nature set to incredible images, you can't really beat Terrance Malick. He never seems to bother too much with characters or story, but he has this amazing way of creating films as if they were visual poems.

Posted by: @icarus

I think they could very easily go down the route of showing a stunning visual montage of the universe being created, set to an awe inspiring orchestral soundtrack with operatic singers... if only because it's been done countless times before.

...

Therefore I think if you really want to wow audiences, you have to do something a bit more daring and unique.

Well... technically, here with The Magician's Nephew, we DO have something a bit more daring and unique. It's a world being created — in fact, sung into being — by a Lion. It's not an operatic chorus, except for the bit where the stars sing; in fact, since the underlying theological point here is that there is one Creator, it really needs to be clear that the singer is a solo voice (though obviously with an otherworldly quality and a huge range of tones and moods), so that no-one gets the impression that there are multiple deities involved in this, even before the new sun rises and reveals who and what the singer is. 

I still really can't fathom how any film-maker is going to do this scene justice, but I'd love to see someone at least try, some day...

As I've mentioned in another thread, they will obviously have to get the right composer, especially for this scene. There actually isn't really anyone I have in mind. I've thought of either Hans Zimmer or Howard Shore. Hans Zimmer scored the music for The Lion King and The Prince of Egypt. Howard Shore is best known for The Lord of the Rings Film Trilogy.

Whichever composer they get (I'm sure we'll hear something before too long), this scene can be done both visually and musically.