In the lighthouse model:
A)pulsars are observable only if they lie in the galactic plane.
B)pulsars are navigational devices created by interstellar navigators as discovered by JocelynBell in 1967.
C)all pulsars have their poles pointed directly at us or they would not be observable.
D)if the beam sweeps across us, we can observe the pulse.
E)the period of pulsation must speed up as the neutron star continues contracting.

Question

Quizplus · Accepted Answer

The lighthouse model describes pulsars as beams of radiation that rotate like a lighthouse. The beam must sweep across us in order for us to observe the pulse. Therefore, choice D is the correct statement. The other choices, A, B, C, and E, are incorrect statements about pulsars. The lighthouse model states that pulsars emit beams of electromagnetic radiation that sweep across space like the beam of a lighthouse. Therefore, if the beam sweeps across us, we can observe the pulse. Choices A, B, C, and E are not accurate descriptions of the lighthouse model.

In the Lighthouse Model