When you're comparing two currencies, isn't the rise of one of them the definition of the other one weakening?  I'm no economist nor a currency trader, but that's been my understanding--please correct me if I'm wrong.

My take on why bitcoin is rising (along with precious metals and stocks) is that there's too much cheap money available to traders, and they're taking full advantage of it.  When interest rates are near zero, margin trading goes up and usually stock prices do as well--or any asset that you can buy using leverage, and that includes cryptocurrencies.  On top of all that, there's all of this "stimulus money" being handed out to people, and a lot of them are using it to speculate in various markets. 

No surprise then that assets which aren't usually correlated start moving upward in tandem, which is exactly what we're seeing right now.  One good thing is that bitcoin hasn't started moving into bubble territory, which makes me glad.  There's all this talk about hitting a new ATH, but I'm hoping that doesn't happen for a few years.