The uncertainty of science: What had originally been thought to be the first image ever taken of an exoplanet has now turned out to be only the fading and expanding cloud of debris, left over from a collusion.

The object, called Fomalhaut b, was first announced in 2008, based on data taken in 2004 and 2006. It was clearly visible in several years of Hubble observations that revealed it was a moving dot. Until then, evidence for exoplanets had mostly been inferred through indirect detection methods, such as subtle back-and-forth stellar wobbles, and shadows from planets passing in front of their stars.

Unlike other directly imaged exoplanets, however, nagging puzzles arose with Fomalhaut b early on. The object was unusually bright in visible light, but did not have any detectable infrared heat signature. Astronomers conjectured that the added brightness came from a huge shell or ring of dust encircling the planet that may possibly have been collision-related. The orbit of Fomalhaut b also appeared unusual, possibly very eccentric. “Our study, which analyzed all available archival Hubble data on Fomalhaut revealed several characteristics that together paint a picture that the planet-sized object may never have existed in the first place,” said Gáspár.

The team emphasizes that the final nail in the coffin came when their data analysis of Hubble images taken in 2014 showed the object had vanished, to their disbelief. Adding to the mystery, earlier images showed the object to continuously fade over time, they say. “Clearly, Fomalhaut b was doing things a bona fide planet should not be doing,” said Gáspár.

The interpretation is that Fomalhaut b is slowly expanding from the smashup that blasted a dissipating dust cloud into space. Taking into account all available data, Gáspár and Rieke think the collision occurred not too long prior to the first observations taken in 2004. By now the debris cloud, consisting of dust particles around 1 micron (1/50th the diameter of a human hair), is below Hubble’s detection limit. The dust cloud is estimated to have expanded by now to a size larger than the orbit of Earth around our Sun.

This is not the first exoplanet that astronauts thought they had imaged, only to find out later that it was no such thing.

Remember this when next you hear or read some scientist telling you they are certain about their results, or that the science is “settled.” Unless you can get close enough to get a real picture in high resolution, or have tons of data from many different sources over a considerable period of time, and conclusions must always be subject to skepticism