On 26 October 2018, Loeb and his postdoc Shmuel Bialy submitted a paper exploring the possibility of Oumuamua being an artificial thin solar sail accelerated by solar radiation pressure, in an effort to help explain the object's comet-like non-gravitational acceleration. Other scientists have stated that the available evidence is insufficient to consider such a premise, and that a tumbling solar sail would not be able to accelerate. In response, Loeb wrote an article detailing six anomalous properties of Oumuamua that make it unusual, unlike any comets or asteroids seen before. A subsequent report on observations by the Spitzer Space Telescope set a tight limit on cometary outgassing of any carbon-based molecules and indicated that Oumuamua is at least ten times more shiny than a typical comet. The solar sail technosignature hypothesis is considered unlikely by many experts owing to available simpler explanations that align with the expected characteristics of interstellar asteroids and comets.