Speculation has turned to what could be powering such light. Loeb has suggested possibilities ranging from a rare fragment of a supernova core rich in radioactive elements, to a nuclear-powered engine created by an intelligent civilisation. ‘3I/ATLAS could be a spacecraft powered by nuclear energy, and the dust emitted from its frontal surface might be from dirt that accumulated on its surface during its interstellar travel,’ Loeb wrote in a statement according to Daily Mail. He admits both ideas are unlikely but argues they cannot yet be dismissed. Normal cometary activity, dust and gas evaporating under solar heat, does not fit the unusual dimming pattern. Nor does the absence of a visible coma, which is expected around comets.