Simple (and possibly really "noob") question about exchanges:

When there is a big green (or red) dildo on the BTC/USD chart of an exchange (say, due to one big whale's move on that specific exchange), how is it possible for nearly all other exchanges, and even different fiat currency charts (BTC/EUR, etc.), to also reflect that move almost instantly? Shouldn't that specific move affect only the exchange in which it was made? At least in the short term?

It seems to me that all exchanges are somehow linked together, so that a move in one of them near-instantly affects all others. I wonder if there is an established inter-exchange system of price equalization (possibly a proactive measure to prevent arbitrage), or if the observed price equalization just happens naturally due to the global market itself (i.e., the "law of averages" taking place).

Have always wondered about this... Any insights appreciated.