Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of broad-spectrum solar power expert SunPower (Nasdaq: SPWRA) sunk behind a dark cloud this morning, falling as much as 10.1% on above-average volume.

So what: Chinese rival LDK Solar (NYSE: LDK) just slashed guidance due to pricing pressures even as the Semiconductor Equipment and Materials International association lamented Chinese companies stealing American solar-power jobs and sales.

Now what: LDK is just the latest in a long line of solar specialists sounding alarm bells, following similar warnings from ReneSola (NYSE: SOL), SunPower itself, and Yingli Green Energy (NYSE: YGE), among others. Collapsing product prices tend to strike pretty equally across entire sectors, you know.

There's no doubt that solar power will play an important part in future energy markets, but the industry is due for a shakeout before we get there. Evergreen Solar already filed for bankruptcy, and there will be more to come. The survivors will make you rich -- but we don't know exactly who's in that group yet. Keep a close eye on this market, but don't catch a bag full of falling knives.

Interested in more info about SunPower? Click here to add it to My Watchlist.

Fool contributor Anders Bylund holds no position in any of the companies mentioned. We Fools may not all hold the same opinion, but we all believe that considering a diverse range of insights makes us better investors. Check out Anders' holdings and bio, or follow him on Twitter and Google+. We have a disclosure policy.