Next year, YouTube will launch roughly 100 channels in collaboration with entertainment heavyweights like Madonna, Ashton Kutcher and Emmy-nominated producer Anthony Zuiker (CSI).

A couple of major production companies are linked to the new online channels, including Lionsgate and FremantleMedia (co-producer of The X Factor).

YouTube is also partnering with a number of prominent media outlets such as The Wall Street Journal, Thomson Reuters and Slate to generate original content.

YouTube’s latest foray into original television programming has critics asking a couple of important questions. First, why is the company doing this? Second, will these new channels be a cable TV killer?

“Cable television expanded our viewing possibilities from just a handful of channels to hundreds, and brought us some of the most defining media experiences of the last few decades – think MTV, ESPN and CNN,” YouTube’s global head of content partnerships wrote in a blog post, adding that YouTube hopes to do the same with its upcoming channels.

Eweek’s Clint Boulton points out that adding professionally-produced content could help YouTube increase the amount of time users spend on the popular site; these new channels are expected to generate about 25 hours of unique content a day.

The Daily Mail’s Rob Waugh writes that many advertisers aren’t keen on running ads before user-generated videos. So adding more branded channels is a smart business move.

Let’s keep in mind that Google is shelling out about $100 million for these new channels. As All Things D notes, that’s not that much for Google (considering how much revenue YouTube is expected to generate this year).

Mainstream TV shows and movies are made on million dollar budgets; the latest Transformers movie alone reportedly had a production budget of nearly $200 million. It will probably take more than $100 million to take down cable TV. But for that price, it’s certainly worth a try.