Moving toward December’s wintry weather, fewer of us are likely to venture out into Bend’s chilly evenings to observe stars. So, let’s talk about stars that are not visible to the human eye anyway.

Bizarre almost beyond comprehension, pulsar stars defy imagination as one of the strangest types in the heavens. Pulsars were so baffling that, for a time, the first one discovered was referred to as LGM-1, standing for Little Green Men 1. At the time, no known mechanism could explain radio signals received from LGM-1. In fanciful speculation, some astronomers suggested that extraterrestrials might be responsible.

Spinning at an incredible 1.3373 revolutions per second, the star sends out pulses that can be picked up by radio receivers and heard as rapidly clicking sounds. In today’s vernacular, astronomers and physicists might have asked, “What’s up with that?”

The “up” part of the question was comparatively easy. LGM-1 was measured to be nearly 2,300 light years away in the constellation Vulpecula. Currently accepted models describe pulsars as spinning neutron stars of incredible density. Under “normal” gravitational fields, neutron stars cannot form. A principle of quantum mechanics disallows it. But, under conditions of extreme gravity, generated by incredibly massive stars, normal atoms can no longer exist. Electrons are forced into protons, converting them into neutrons, thus creating neutron stars. Neutron stars can result from the gravitational collapse of massive stars during supernova explosion events. A single teaspoon of neutron star material could weigh as much as a billion tons. How can this astounding assertion be true?

In a neutron star, almost all of the space between the parts of an atom disappears, and nuclear mass is concentrated to an extent unimaginable to nearly all but the scientifically minded. Equally difficult to grasp, a neutron star is hypothesized to possess an atmosphere, albeit only a few micrometers thick. In this area, electrons still exist, creating a magnetic field. It is this field that generates the radio waves we detect. These waves emanate from the star’s magnet poles like the rotating beam of a lighthouse. If the beam sweeps across Earth, it produces a radio click.

Alas, no Little Green Men.

— Kent Fairfield is a volunteer with Pine Mountain Observatory and a lifelong amateur astronomer. He can be reached at kent.fairfield@gmail.com. Other PMO volunteers also contributed to this article.