When btc gets a dump, and the same microsecond the alts get a dump as well, it cannot be people being greedy/fearful, right? it must be a coupling in some form to the mastercoin, btc?
im not saying anything about the intrinsical value of an alt itself, nor if its a good or a bad alt, but just these fluctuations intrigue me and i dont really understand...
Not sure I understand your question : the answer seems self evident :
There is trading constantly on multiple exchanges 24/7, every second of the day. The alt prices (on coinmarket cap or whatever) are based on 'last trade' for a number of exchanges. The trade is in BTC, that is converted to $$ in the quote. If BTC $ price changes, then so must the alt $ price, even if there is no further trade.
If a bid/offer is hit then the BTC price changes as well.