system
Given the following post, respond as if you're commenting on Reddit:
human
Did Top Gear really find the source of the Nile and are they the first?

Reddit seem to be fairly avid watchers of Top Gear so I assume most people know that in their end of season special they attempted to find the 'true' source of the Nile in £1500 estate cars. They claimed that no one had truly found the source and that some explorers have claimed to have found it but that this was not the case. They succeeded in finding a spring somewhere to the South East of Lake Victoria that feeds it and ultimately into the Nile. Could someone clarify specifically what they mean by the source, why it hasn't been found yet and just general information about the geological side of these episodes?
gpt
One definition of a river's source is the tributary starting farthest from the river's mouth. Using the point where the Nile empties into the Mediterranean as its mouth the possible sources of the Nile are on the west side of Lake Victoria.

For the Top gear special they redefined the mouth of the Nile from its delta in Egypt to the Strait of Gibraltar where the Mediterranean meets the Atlantic. Using that definition of the Nile's mouth the streams on the East side of Lake Victoria are suddenly the candidate sources instead of those on the West. Allowing them to "discover" the "true" source of the river.

Problem is defining the Strait of Gibraltar as the mouth of the Nile is really really stupid. So, no, they did not find the true source of the Nile.