A newly discovered celestial visitor, Comet C/2025 R2 (SWAN), is expected to pass by Earth on October 21, offering stargazers across the globe a rare chance to witness a glowing comet visible even to the naked eye. Discovered last month by a Ukrainian amateur astronomer, the comet has been rapidly brightening as it nears the Sun, making it one of the most anticipated astronomical events of the year.
SWAN Comet Discovered by Amateur Astronomer
The Comet C/2025 R2 (SWAN) was discovered on September 10, 2025, by Vladimir Bezugly, an amateur astronomer from Ukraine. Since its detection, the comet has garnered attention from observatories and skywatchers alike due to its unusual brightness and proximity to Earth.
As the comet travels closer to the Sun, the solar heat causes its icy nucleus to undergo sublimation, a process where frozen gases turn directly into vapor. This creates a luminous shell of gas and dust, forming the comet’s iconic glowing tail that can stretch millions of kilometers through space.
On September 12, the comet reached its perihelion, or closest point to the Sun, passing within 47 million miles (75 million km) of our star — roughly half the distance between the Sun and Earth. Since then, its visibility has steadily increased, making it a target of excitement for the global stargazing community.
When and Where to See Comet C/2025 R2 (SWAN)
According to astronomers, October 21 marks the date when Comet C/2025 R2 (SWAN) will make its closest approach to Earth, a phenomenon expected to offer the best viewing opportunities, as per a report by Space.
The comet will be visible in the evening sky throughout October, particularly in the hours just after sunset. Skywatchers in dark, rural areas with minimal light pollution stand the best chance of spotting it without optical aid.
On October 16, the comet is expected to appear about five degrees to the upper left of the star Xi Serpentis, located in the constellation Serpens. By the following week, it will move past the "teapot" asterism in Sagittarius, gliding toward the Scutum constellation. Toward the end of October, it will be seen above the southern horizon, between the bright stars Sadalmelik and Sadalsuud in Aquarius, with the half-lit Moon below it adding to the celestial display.
For those new to astronomy, experts recommend using stargazing mobile applications like Stellarium or Sky Guide to help locate the comet’s position in real time.
How Bright Will the SWAN Comet Be?
Recent readings from the Comet Observation Database (COBS), maintained by the Crni Vrh Observatory in Slovenia, indicate that Comet C/2025 R2 (SWAN) currently boasts a brightness magnitude of 5.6.
This suggests that, under ideal dark-sky conditions, the comet might already be faintly visible to the naked eye. For reference, the human eye can detect celestial objects up to magnitude +6, provided there is minimal atmospheric and light interference.
However, astronomers note that binoculars or a small telescope will greatly enhance visibility, revealing more of the comet’s signature greenish coma and elongated dust tail.
Understanding the Science Behind the Spectacle
Comets like C/2025 R2 (SWAN) are remnants from the early solar system, composed of ice, rock, and organic compounds. As they approach the Sun, they provide rare insights into the primordial materials that shaped the planets billions of years ago.
In the case of SWAN, its increasing brightness has been attributed to heightened sublimation activity, a process in which frozen carbon dioxide, methane, and water vapor erupt from its surface. These emissions, illuminated by sunlight and pushed outward by the solar wind, create the striking tail visible from Earth.
Scientists are closely monitoring SWAN’s trajectory to better understand its behavior and determine whether it may produce any outbursts or fragmentation during its flyby.
How to Prepare for Viewing the Comet
Astronomy enthusiasts are advised to find a dark observation spot away from city lights for the best viewing experience. The ideal viewing window is between 7:30 PM and 9:30 PM local time, when the comet is at its highest above the horizon, as per the report by Space.
Basic equipment, such as 7x50 binoculars or small telescopes, can provide remarkable views of SWAN’s tail structure. For those interested in astrophotography, DSLR cameras equipped with wide-angle lenses and long exposure settings are recommended to capture the comet’s faint glow against the starry backdrop.
A Rare Treat for Stargazers Worldwide
While 2025 has already seen several notable celestial events, including supermoons and planetary alignments, the appearance of Comet C/2025 R2 (SWAN) stands out as a rare spectacle. The comet’s proximity to both the Sun and Earth during its October passage provides an exceptional opportunity for both amateur and professional astronomers to observe a dynamically evolving comet in real time
Even if the comet doesn’t reach peak naked-eye visibility, its brightness through optical instruments is expected to delight observers across North America, Europe, and Asia.
Source: The Economic Times
Bd-pratidin English/ ANI
