Kolkata: This winter, stargazers in Kolkata are in for a celestial treat as Mars makes its closest approach to Earth and reaches opposition with the Sun, presenting a spectacular view of the Red Planet. The phenomenon began on Dec 7, 2024, when Mars entered its retrograde motion, and will peak with two key astronomical events in Jan 2025 — Mars' closest approach to Earth on Jan 12 and its opposition with the Sun on Jan 16. During this period, Mars will appear exceptionally bright and large in the night sky, easily visible to the naked eye and a prime target for telescope enthusiasts.
Mars' reddish hue will be more pronounced as Earth aligns directly between Mars and the Sun. This alignment not only brings Mars closer but also illuminates its surface fully, allowing even moderate telescopes to reveal features like polar ice caps. However, the waxing and waning phases of the moon around this time — culminating in a full moon on Jan 14 — might slightly diffuse the clarity of Mars' visibility due to the brightness of the lunar disc, said Bipash Das Gupta, scientific officer of MP Birla Institute of Fundamental Research.
Historically, such close encounters between Earth and Mars occur approximately every 26 months. This time, the two planets will be separated by about 96 million kilometres at their nearest point, a stark contrast to their farthest distance of 403 million kilometres. Mars last came extraordinarily close in Aug 2003, when it was 56.4 million kilometres away — a record that will not be broken until Aug 28, 2287.
For the best viewing experience, astronomers recommend looking east after sunset, where Mars will rise and continue to shine brightly throughout the night. It will be located in the Cancer constellation, with its size appearing at 14.5 arc-seconds and its magnitude at -1.4, making it one of the brightest objects in the night sky.
Mars' retrograde motion, which gives the illusion of the planet moving westward against the backdrop of stars, has intrigued sky-watchers for centuries. This apparent motion is a result of Earth overtaking Mars in its orbit around the Sun. The phenomenon, now well-understood, once puzzled ancient astronomers and added to the mystique of the Red Planet, Das Gupta added.
The Red Planet holds a special place in both science and imagination. While its thin atmosphere and harsh surface conditions make it inhospitable to life as we know it, Mars shares many similarities with Earth, such as tilted axes that produce seasons. Observations during this period offer a rare opportunity to study Mars in detail, from its polar ice caps to its massive dust storms.
Kolkata's winter skies, typically clear and crisp, offer the perfect setting for this celestial show. Amateur and professional astronomers alike are encouraged to seize the opportunity to observe Mars with telescopes for a richer experience, despite the lunar brightness. Six planets will be visible in the evening sky on Jan 12, including Mars from the western to eastern sky in a diurnal arc. On Jan 12 and 16, Bipash Das Gupta will deliver an expert interpretation at UEM Observatory, New Town.