Is Chromecast capable of streaming 4k video?

There is some 4k content on Youtube, but I don't have a 4k TV to attempt this experiment (and I don't really feel like throwing down thousands of dollars just to try it out). Can anyone confirm whether the Chromecast will stream 4k Youtube videos (or 4k content from any other source)?

Does it stream at all? Does it actually stream in 4k? Perhaps it streams but just at a lower fidelity resolution, but perhaps still higher than 1080p (not sure how you'd tell this, but whatever)? Your thoughtful and/or informed replies are appreciated, thanks!