Final answer:
Rapid pulses of radio radiation observed from the constellation of Vulpecula led to the discovery of pulsars, which are rotating magnetic neutron stars. This discovery expanded upon earlier scientific investigations into electromagnetic radiation, such as the identification of X-rays and the characterization of nuclear radiation.
Step-by-step explanation:
A source of rapid, sharp, intense, and extremely regular pulses of radio radiation led to the discovery of pulsars. Discovered by Jocelyn Bell Burnell in the constellation of Vulpecula, this enigmatic signal was received every 1.33728 seconds and was first humorously attributed to "little green men" due to its artificial-seeming regularity. However, as more of these sources were found, scientists recognized them as a new astronomical phenomena, now understood to be a rotating, magnetic neutron stars acting as lighthouses in the cosmos. Originally, over 2500 pulsars were known, and as of today, nearly 3000 have been discovered, eliminating the possibility that these were signals from extraterrestrial intelligences.
These findings underscore the continual unfolding of our understanding of the universe, tracing back to earlier work with cathode rays and the discovery of the X-ray by scientists like Faraday. Further groundbreaking research identified different types of nuclear radiation, alpha, beta, and gamma rays, from the core of atoms which, unlike electron transitions, did not vary based on chemical states or external conditions, hinting at their nuclear origin.