If you think that the concept of ghosts only applies to Earth, think again. Space scientists recently admitted that that our erstwhile closest Earth-like neighbour circling the star nearest our galaxy is, in fact, just a ghost.

When Alpha Centauri Bb, a world in the nearest star system to us, was discovered in 2012, the scientific world was filled with excitement, primarily due to the fact that the search for alien life felt like within reach.

Alpha Centauri Bb was originally found some 4.37 light years away from the Earth, circling the main sequence star, Alpha Centauri B, once every 3.24 days—an extraordinarily fast orbit.

Researchers from the University of Oxford, however, recently made a shocking discovery: Alpha Centauri Bb was just an illusion.

Vinesh Rajpaul, who led the team that verified the discovery of Alpha Centauri Bb, said the exoplanet was little more than a "ghost" generated by a disparate set of measurements.

"The detection was a contentious one, with some voicing reservations about the modelling approach used to infer the planet's presence," Rajpaul said, as quoted by The Daily Mail.

"We have demonstrated that the 3.24-day signal observed in the Alpha Centauri B data almost certainly arises from the window function of the original data," he further explained.

This finding also explains why other teams of astronomers who tried to spot Alpha Centauri Bb before could not do so if they did not use the La Silla observatory in Chile, where the original discovery was made.

Rajpaul nevertheless said the error was not the fault of the original team that detected the signal and could not have been anticipated.

These recent findings about Alpha Centauri Bb will also be used to countercheck if recently spotted exoplanets are indeed real, or are also mere illusions.

"We are still hoping there are other planets in the system. We just have to find better techniques to detect them," Rajpaul said.