Question

Anne: Halley’s Comet, now in a part of its orbit relatively far from the Sun, recently flared brightly enough to be seen by telescope. No comet has ever been observed to flare so far from the Sun before, so such a flare must be highly unusual.

Sue: Nonsense. Usually no one bothers to try to observe comets when they are so far from the Sun. This flare was observed only because an observatory was tracking Halley’s Comet very carefully.

Sue challenges Anne’s reasoning by

A. pointing out that Anne’s use of the term "observed" is excessively vague
B. drawing attention to an inconsistency between two of Anne’s claims
C. presenting evidence that directly contradicts Anne’s evidence
D. offering an alternative explanation for the evidence Anne cites
E. undermining some of Anne’s evidence while agreeing with her conclusion

Answer 1

Sue counters Anne's claim about Halley's Comet's unusual flare by suggesting that it was only observed because astronomers were specifically tracking it, not because it is an inherently rare phenomenon.

Step-by-step explanation:

Sue challenges Anne's reasoning by offering an alternative explanation for the evidence Anne cites. Anne's claim was that Halley's Comet flaring so far from the Sun must be highly unusual because no comet has ever been observed to flare at such a distance, but Sue contends that this flare was observed only because of the specific circumstances under which astronomers were tracking Halley's Comet. Given that observational records for comets, including Halley's Comet, exist which detail historical passes near the Sun, and the existence of spacecraft like the ESA/NASA's Solar and Heliospheric Observatory (SOHO) that allow us to find comets near the Sun, Sue's point that comets far from the Sun are not usually observed does not lack merit.