Surveying the night sky five years ago, a group of astronomers picked up a signal from a pulsar located in the binary system known as JJ906. Just as surely as it appeared spontaneously, the star recently blinked out of view without a trace.

Scientists believe that the pulsar’s electromagnetic beacon, which was trained squarely within visible range from Earth, has been obscured by a tilt in space-time caused by the gravity of both stars in the system. This phenomenon, backed up by Einstein’s Theory of Relativity, is called geodetic precession.

A pulsar, or neutron star, is the remnant of an exploded star. Similar to a snake shedding its skin, explosive supernovas rid stars of their outer layer, leaving only a crushed core. Only, when it comes to pulsars, the skin doesn’t regrow.

These neutron stars create potent beams of X-rays, gamma rays, radio and visible light through a swiftly moving magnetic field that slows as time passes, according to NASA. Once the pulsar’s magnetic field halts, so do the aforementioned beams.

“[Pulsars] pack more mass than our Sun has in a sphere that’s only 10 miles across,” explains study author Dr. Joeri van Leeuwen.

The team found that the gravity which moved the star out of view causes the pulsar’s axis to shift by two degrees each year.

Fellow team member Professor Ingrid Stairs adds, “By precisely tracking the motion of the pulsar, we are able to measure the gravitational interaction between the two highly compact stars with extreme accuracy…The resulting extreme gravity causes many remarkable effects.”

Dr. van Leeuwen describes the first sighting of JJ906 as a “Eureka moment” because astronomers had combed over that space in the sky routinely and never found a thing previously. He expects that the pulsar will become visible again in 2170, reports BBC News.

The study was originally published in the peer-reviewed publication The Astrophysical Journal and announced at the American Astronomical Society’s most recent conference.