NARRATOR：

Now listen to part of a lecture on the topic you just read about.

FEMALE PROFESSOR：

There is no solid evidence that Robert Peary reached the North Pole.

The arguments cited in the reading selection are not convincing.

First, it is true that the National Geographic Society committee declared that Peary had indeed reached the North Pole, but the committee was not completely objective.

In fact, the committee was composed of Peary’s close friends who had contributed large sums of money to fund Peary’s trip.

Moreover, the investigation lasted only two days, and according to Peary himself, the committee did not examine his records carefully.

So, the committee’s conclusions seem biased and therefore are not trustworthy.

Second, the speed issue. Tom Avery’s journey was different from Peary’s in important ways.

For example, Avery’s sled was similar to Peary’s sled, but Avery carried much less weight than Peary did because Avery did not transport his food on the sled.

Avery’s food was dropped along the way by airplane.

Moreover, Avery encountered highly favorable weather conditions, unlike Peary, who traveled in very unfavorable conditions.

So Avery’s speedy trip was too different from Peary’s to provide support for Peary’s claims.

Third, the photographs do not prove anything. The techniques scientists use to determine the Sun’s position depend on measuring the shadows in the photographs very precisely.

Without a precise measurement of the shadows, we cannot establish the Sun’s exact position.

Now, Peary’s pictures were photographed 100 years ago using a primitive camera that took fuzzy, slightly unfocused photographs.

Moreover, the photos have become faded and worn over time.

As a result, the shadows in Peary’s photographs look blurred and faded.

Those shadows cannot be used to calculate the position of the Sun with great accuracy, so we cannot be confident the photos were really taken at the North Pole.