Symphony of Science is a series of music videos by John Boswell, using "remixing and tuning [of] spoken word, combined with original electronic music and similarly themed footage". The videos are made up of clips from various science documentaries and other videos, featuring numerous scientists and skeptics, primarily Carl Sagan. The first video was released last september, and the sixth video was just released yesterday. There were some legal issues from Sagan's widow, Ann Druyan, over further use of his footage, but these seem to have been dropped.

The videos appear in reverse order on the site. There are mp3, flac and video downloads for all songs, as well as lyrics.

The following are Youtube links. The first three go up to 480p resolution, and the subsequent videos go up to 720p. Obviously there is some variation in the quality of source material.

1. A Glorious Dawn
2. We Are All Connected
3. Our Place in the Cosmos
4. The Unbroken Thread
5. The Poetry of Reality
6. The Case for Mars
7. A Wave of Reason
8. The Big Beginning
9. Ode to the Brain!
10. Children of Africa: The Story of Us
11. The Quantum World!
12. Onward to the Edge!
13. The Greatest Show on Earth!
14. The World of the Dinosaurs
15. We Are Star Dust
16. Our Biggest Challenge (Climate Change)

Spinoffs:
The Symphony of Bang Goes The Theory in partnership with BBC.
TED2012 remixed: It's Time for TED.

There are also various other remixes posted on Boswell's channel, as well as remixes created for PBS.

Edit: Song 16 added.

5. and 2. are my favourites

Thanks. Now I can spend of friday evening just thinking how small I am and how wast everything is. Just marvelous.

Nice, I love it. I agree with lackoo.

Those were great, thanks. I'd only heard the first before - didn't even know the others existed.

You can never get too much of Carl Sagan.

I can't decide whether these are awesome or awful. They may be both. I love them either way.

Bump. After nearly six months, a new song has been released, A Wave of Reason.

Part of the reason for the delay was issues with obtaining permissions, particularly with regards to footage of Carl Sagan.

Great lyrics, sh..ty vocals. I mean, someone did a lot of work, kudos to him, but the vocoders are so annoying, and weren't a good idea in music in the first place. Still, worth watching, thanks!:)

Bump again, new song, The Big Beginning.

I heard about these last year from some friends. They are awesome.

Awesome. I missed this thread before.

Bump, new song and spinoff.

Song 10 released.

These actually sound pretty good.