Western Space

A comet first spotted by scientists less than a year ago will be flying by Earth for the first time in roughly 50,000 years and won’t be seen again for thousands of years. Comet C/2022 E3 (ZTF) has been dubbed the “Green Comet” because of the greenish hue it is expected to give off. Those eager to get a glimpse of the comet are invited to a Public Night at Western’s Hume Cronyn Memorial Observatory on Saturday, Jan. 28. Physics and astronomy professor Paul Wiegert studies the dynamics of asteroids, comets and meteoroid streams, and answered questions about the significance of C/2022 E3 (ZTF).   We’ve only known about this comet since last year. How was it discovered? This comet was discovered in March 2022 by the Zwicky Transient Facility (ZTF) working at the Palomar telescope in California, as part of its survey for near-Earth asteroids. This comet is coming to us from the very edge of our Solar System. It orbits the Sun. What is special about C/2022 E3 (ZTF)? Every comet, like every snowflake, is unique. Comet ZTF is special because of how close it is passing by Earth. Though not passing close enough to be dangerous, it means astronomers get a particularly good view as it sweeps past and then back out into deep space again. What can we learn from this comet? While our planet only takes a year to make its journey around our star, Comet ZTF takes tens of thousands of years. Comets that arrive from these distant regions may have delivered water to early Earth, and contain important clues about the chemistry of star and planet birth. While we don’t have an extensive study of this comet planned, scientists at Western are working to monitor the path and brightness of the comet as it swings by our planet. Why does the comet appear green? Comets contain carbon-bearing molecules, which break down under ultraviolet light from the Sun. This produces, among other things, dicarbon molecules which produce the eerie green glow associated with some comets. The comet will be most visible around Feb. 1. How can we see it? The comet should be easily visible through binoculars or a small telescope, but it is trending to be too faint for the human eye to see, except perhaps from a very dark site. However, a comet’s brightness is notoriously hard to predict so we might be surprised. The trick in this case is to figure out exactly where to look, as the comet is moving across the sky fairly quickly. There are a number of online maps and planetarium apps that can help you plan a viewing. Western’s on-campus Hume Cronyn Memorial Observatory will be hosting a Public Night from 7 to 9 p.m. on Saturday, Jan. 28. I’ll be giving a short presentation on the secrets of comets and the telescopes will be open for viewing of the comet if weather permits.