July 31, 2021

Space: the “largest comet of modern times” is heading towards our solar system

She comes from a place so far away that it remains a mystery, even to the most eminent scientists. However, comet Bernardinelli-Bernstein, or C / 2014 UN27, has presumably decided to visit us. Spotted in mid-June, this celestial body follows a path that should take it through our solar system.

The meeting is not scheduled for immediately since C / 2014 UN27 will reach its closest point to our Sun in 2031. In the meantime, astronomers intend to keep their eyes on this giant comet coming from the cloud d’Oort, which surrounds the solar system.

This unfathomable sphere made up of frozen objects is located more than 40,000 astronomical units (AU) from the Sun, a distance 40,000 times greater than that which separates the solar star from the Earth, according to the National Laboratory for Optical Astronomy Research. -infrared from the American Foundation for Science (NOIRLab).

A very long trip, therefore, for a very large comet. Astronomers agree in fact that it is the greatest “discovery in modern times”. A priori “1,000 times more massive than a usual comet”, its diameter is estimated between 100 and 200 kilometers.

Despite its impressive measurements, C / 2014 UN27 should not be feared: it does not represent any danger for the Earth. During its closest passage to the Sun, in 2031, it will remain too far away to be visible to the naked eye from the blue planet.

A “huge calculation problem”

But, equipped with state-of-the-art equipment, the scientists will not miss a thing of the show. Even if it was already observed in 2014, this giant comet, by its unique constitution and its origin, represents a precious opportunity to learn more, in particular about the formation and the movement of celestial bodies.

Just to detect its presence last June, astronomers Pedro Bernardinelli and Gary Bernstein of the University of Pennsylvania had to study six years of data accumulated as part of the Dark Energy Survey (DES). This international program attempts in particular to unravel the mystery of dark energy by mapping hundreds of millions of galaxies.

“The research itself took between 15 and 20 million hours for processors, specifies Pedro Bernardinelli on Twitter. Finding transneptunian objects with DES is a huge computational problem ”. Moreover, for several years, from 2014 to 2018, the images provided by DES did not make it possible to distinguish a “tail” in the composition of C / 2014 UN27.

A characteristic element of comets, the latter is formed by evaporation, when these icy bodies approach the heat of the Sun. The hair, or coma, of C / 2014 UN27 has finally appeared on recent photos, allowing it to be formally identified as a comet. A decisive step in the knowledge of this extraordinary celestial body, which has not yet revealed all its secrets.