Originally Posted by Mjölnir
She doesn't just stumble upon it. They are researching it and they aren't in London for no reason. When they come to the site of the anomalies she discovers a new reading, which is the Aether. It's of course an unlikely event, but if the Aether was hidden well then it would take something unlikely to find it.
It was my understanding that the anomalies aren't from the Aether but from upcoming converge. But I could be wrong.