Finding the island with a special Foucault pendulum
So let's say you'd like to travel to the island. Well, first you have to find it. And since it's never in the same place at any given time, that can be extremely difficult.
Luckily for you, some scientists in the 1970s created a laboratory in Los Angeles specifically to track the island's four-dimensional movements. By using a Foucault pendulum that is attuned to the island's unique electromagnetic signature, the lab can follow the island's movements in relation to the Earth's rotation. Once you locate the island, though, you must move quickly to get there as it is just as liable to disappear completely again within the span of a week.