From an observational standpoint, what is a pulsar?
A) A star that slowly changes its brightness, getting dimmer and then brighter, with a period of anywhere from a few hours to a few weeks.
B) An object that emits flashes of light several times per second (or even faster), with near perfect regularity.
C) An object that emits random "pulses" of light, sometimes with only a fraction of a second between pulses and other times with several days between pulses.
D) A star that changes color rapidly, from blue to red and back again.

Question

Quizplus · Accepted Answer

A pulsar is an object that emits regular pulses of electromagnetic radiation, usually in the form of radio waves, but also visible light, X-rays, and gamma rays. These pulses are incredibly regular, with some pulsars emitting hundreds of pulses per second.

From an Observational Standpoint, What Is a Pulsar