Reference no: EM133346783
Case: In January, 1989, John Middleditch and his colleagues went to the Cerro Tololo Inter-American Observatory in Chile with an exceptionally sensitive new light detector to look for the pulsar that was assumed to have been formed in the supernova. Pulsars, which can contain the mass of the sun in a body no more than 10 miles across, rotate extremely rapidly, emitting pulses of light like the beacon of a lighthouse at regular intervals of small fractions of a second.
As soon as they turned on the detector, "a signal that looked like a pulsar came blasting through," Middleditch said Monday. "The data looked really good; it had features in it really indicative of a pulsar." But the object seemed to be rotating exceptionally rapidly, 1,968 times per second. At that speed, it should have flown apart almost instantly, and theorists were hard pressed to develop explanations for its existence.
Other researchers were unable to detect the pulsar, and when Middleditch and his colleagues looked again in July, they couldn't find it either. Most people assumed it was obscured by dust from the supernova.
Two weeks ago, however, team members went back to Cerro Tololo with an even more sensitive detector. They observed the pulsar again. But when they pointed the four-meter telescope at the Crab Nebula, which does not have a pulsar, "the pulsar signal came blasting through again," Middleditch said.
Further examination revealed that the signal was coming either from a television camera on the telescope that is used to orient it, or from an interaction between the camera and the sensitive detectors. Without realizing it, Middleditch's team had switched to a different camera after the initial pulsar observation, and it was not until they happened to use the first camera again that they discovered the problem.
a. If we take the implicit question organizing this passage to be "What caused the signal?", then what conclusion is proposed now as the sound one (call it C1) and what rival did it replace (C2)?
b. Schematize the argument for the suggested conclusion. (Be careful not to semantically eliminate the conclusion.)
c. What evidence could you discover that might alter the plausibility rankings of the two rivals? How does it affect the rankings?