If we go back to the medieval era, we will remember that at that time it was believed that comets were an unmistakable sign that a war, a plague or the death of a king was approaching. Medieval men would have said, in view of the current pandemic of coronaviruses in the world, that it would be the right time for a comet to make its appearance. To this day, we know that comets are dirty snowballs left over from the material that formed the solar system and that they are not related to earthly events, but what is clear is that they will offer us a spectacle worth seeing with our eyes.
History of the comet
The comet C/2019 Y4 (ATLAS) was first discovered on 28 December 2019 and, although we noticed it was rather faint at the time, it seems to have been gaining in luminosity since then, hence astronomers are quite excited about the astronomical event. It has been quite a few years since the last time a comet offered us a good show: it was in March 2013 thanks to the PanSTARRS comet, which was visible, although not with the brightness we expected. The same thing happened with McNaught in 2007 and Lovejoy in 2011.
However, ATLAS is on its way to becoming one of the brightest comets to grace our skies, comparable to the fantastic Hale-Bopp in 1997.
The new comet, named after the telescope that discovered it (ATLAS in Hawaii), has a near-parabolic orbit — meaning that its orbit extends deeper into the cosmos and won’t return to this point for thousands of years — and, according to experts, when it makes its closest approach to the Sun, it will be able to illuminate anywhere on the planet from a visible magnitude of +1 to -5 (the brighter the object, the smaller its magnitude). It is currently magnitude 8 and its brightness is steadily increasing.
However, bear in mind that comets behave quite unpredictably and we might end up with it fading away and missing the big show. However, the fact that it has an orbit very similar to that of a Great Comet which became an incredibly bright object in the night sky in the 19th century (the Great Comet of 1844), gives us hope.
When will it pass close to us?
Its closest approach to the Sun, the perihelion, will be on May 31st and it will pass within 37.8 million kilometres of our star. If its activity continues, we will be able to see the comet’s wake for several weeks. It will be visible after sunset until it disappears completely. Experts predict that comet ATLAS could reach a magnitude of -8.2 at its perigee and -11.7 at its perihelion.
Dozens of comets visit our inner solar system each year, but most are so faint that a telescope is needed to see them. Will ATLAS offer us a different scenario? For the moment, it’s exciting to know that it’s getting brighter and brighter every night. If you’re curious, right now it’s crossing the Big Dipper and moving slowly.