SPRIZZANO from a "foreign" comet coming from another planetary system and could explain how water, a fundamental element for life, travel between the stars. Traces of alien water could therefore be those identified on interstellar comet 2I / Borisov, the new 'intruder' of the Solar System since last August 30 under close observation of astronomers. If the discovery were confirmed, it would show that the comet is very similar to those of 'our home' and would also help us better understand how water moves in the cosmos. This is indicated by a group of astronomers led by Adam McKay of NASA's Goddard Space Flight Center, in a study currently being published on The Astrophysical Journal Letters and appeared on ArXiv, the site that tracks the scientific articles before the revision in view of the official publication.The researchers used a 3.5-meter telescope from the Apache Point Observatory, in New Mexico, to analyze sunlight reflected from the comet Borisov. On 11 October, they thus identified in the luminous spectrum what appears to be the 'signature' of oxygen. Although comets can produce oxygen in different ways, astronomers claim that the most plausible explanation is that oxygen derives from the cleavage of water into hydrogen and oxygen. The estimated water on the comet would be present along with the cyanide (previously identified) according to the same proportions observed in the comets of the Solar System. The astronomers expect to be able to observe more evident traces of water in the coming weeks, when the comet 2I / Borisov will approach the Sun further: the heat will increase the melting of its icy core and consequently the emission of gas and dust.