Last supermoon of year set to light up December skies

Skywatchers will get one final chance in 2025 to see a supermoon, as the last in a trio of consecutive supermoons rises on December 4.

A supermoon occurs when the full moon coincides with the point in its orbit where it is closest to Earth. Because the moon’s orbit is not a perfect circle, its distance varies as it travels around the planet. When alignment brings it nearer during a full moon, it appears larger and brighter, AP writes. 

According to NASA, a supermoon can look up to 14% bigger and 30% brighter than the faintest full moon of the year.

Supermoons tend to arrive in clusters several times a year, taking advantage of the “sweet spot” in the moon’s elliptical orbit. This final event offers viewers a chance to see the moon at its most luminous, though experts note that the difference is often hard to detect without instruments.

The supermoon will be visible in clear night skies with no need for telescopes or special equipment. Still, many observers may struggle to perceive the change in size. Even during a typical full moon, the lunar disk can appear larger when it sits near the horizon because of the well-known “moon illusion,” a visual effect that continues to puzzle researchers.

“When you have a supermoon, that effect is just slightly more striking,” said astronomer William Alston with the University of Hertfordshire.

While the moon’s increased proximity can produce slightly higher tides, scientists say the impact is usually subtle and not easily noticeable during a supermoon.

The December 4 event marks the year’s final opportunity to watch the moon reach its brightest and closest point before the next supermoon cycle begins.

By Sabina Mammadli