<Ul> <Li> When the length of a river is followed by an asterisk, it is an average of multiple information sources . If the difference in lengths between given information sources is significant, all lengths are listed . But if the lengths from secondary information sources are similar, they are averaged and that figure has an asterisk . </Li> <Li> Scientists debate whether the Amazon or the Nile is the longest river in the world . Traditionally, the Nile is considered longer, but recent information suggests that the Amazon may be longer . Differences in the recorded length of the Amazon mainly depend on whether or not it is valid to take a course south of the Ilha de Marajó at the Amazon's mouth . New evidence, (dated 16 June 2007) obtained from a high - altitude scientific venture in the Andes, claims that "the Amazon is longer than the Nile by 100km, with its longest headwater being the Carhuasanta stream originating in the south of Peru on the Nevado Mismi mountain's northern slopes and flowing into the Río Apurímac". However, the origin of the river at Nevado Mismi had already been known more than one decade earlier (see Jacek Palkiewicz), and satellite based measuring from this origin to the Amazon mouth has resulted in not more than 6,400 km . </Li> <Li> Generally, the most commonly used / anglicised name of the river is used . The name in a native language or alternate spelling may be shown . </Li> </Ul> <Li> When the length of a river is followed by an asterisk, it is an average of multiple information sources . If the difference in lengths between given information sources is significant, all lengths are listed . But if the lengths from secondary information sources are similar, they are averaged and that figure has an asterisk . </Li> <Li> Scientists debate whether the Amazon or the Nile is the longest river in the world . Traditionally, the Nile is considered longer, but recent information suggests that the Amazon may be longer . Differences in the recorded length of the Amazon mainly depend on whether or not it is valid to take a course south of the Ilha de Marajó at the Amazon's mouth . New evidence, (dated 16 June 2007) obtained from a high - altitude scientific venture in the Andes, claims that "the Amazon is longer than the Nile by 100km, with its longest headwater being the Carhuasanta stream originating in the south of Peru on the Nevado Mismi mountain's northern slopes and flowing into the Río Apurímac". However, the origin of the river at Nevado Mismi had already been known more than one decade earlier (see Jacek Palkiewicz), and satellite based measuring from this origin to the Amazon mouth has resulted in not more than 6,400 km . </Li> <Li> Generally, the most commonly used / anglicised name of the river is used . The name in a native language or alternate spelling may be shown . </Li>

When did the amazon river become the longest