The valley is the Turquoise Pool, and the Turquoise Pool itself forms a separate space. In this sense, indeed, it might be possible.
However, Su Yang's speculation was quickly overturned.
The old cultivator who had been in the Feather Spirit Palace for over two thousand years was very familiar with the Ancient history. He informed Su Yang that the Nine Realms are connected, so the time in the Nine Realms is the same. Even if the time in the Turquoise Pool is the same as the Human World, there is no concept of double speed.
This left Su Yang bewildered again. If it's not that the time in the Turquoise Pool is faster, then what exactly is the problem here?
Later, it was the same elder who helped Su Yang resolve this doubt.
