In our new paper, Evidence that 1I/2017 U1 (`Oumuamua) was composed of molecular hydrogen ice, we show that all of ‘Oumuamua’s mysterious properties may be explained if it was composed of molecular hydrogen ice.

Schematic diagram showing ‘Oumuamua’s size and shape evolution due to H2 sublimation and its trajectory through the Solar System. Pairs of orientations at three discrete points on the trajectory are shown in the upper left.

Schematic diagram showing ‘Oumuamua’s size and shape evolution due to H2 sublimation and its trajectory through the Solar System. Pairs of orientations at three discrete points on the trajectory are shown in the upper left.

Density, mass and aspect ratio evolution for ‘Oumuamua as it travelled through the Solar System. The periastron passage is displayed at a time, t = 0, and the date of detection (Location 2 in Figure 1) is labeled.

Density, mass and aspect ratio evolution for ‘Oumuamua as it travelled through the Solar System. The periastron passage is displayed at a time, t = 0, and the date of detection (Location 2 in Figure 1) is labeled.

Shape evolution of Oumuamua, under the continuous action of hydrogen ablation.