Brightness of comet ZI/ATLAS decreased by 63 percent

The large space comet named ZI/ATLAS is approaching Earth at high speed, but its brightness has significantly decreased in recent days. This was reported by Zamin.uz.

According to reports based on data from the Russian Space Research Institute, several hypotheses have been proposed regarding the reasons for this situation. Observations from the Solar Astronomy Laboratory indicate that the comet's brightness level, or stellar magnitude, has changed from 10.1 to 10.6.

This means that within just six days, the brightness has decreased by 63 percent. Initially, this seems puzzling because the comet has approached Earth to within 10 million kilometers.

However, instead of increasing, the brightness has been observed to decrease. Experts explain this phenomenon by the comet moving away from the Sun.

It is known that comets appear bright when they reflect sunlight. If the amount of light coming from the Sun decreases, the comet's brightness naturally diminishes.

Additionally, internal processes may also have an effect. For example, changes in the physical structure of the comet's nucleus or a reduction in its light-reflecting ability weaken its visible brightness.

Nevertheless, the ZI/ATLAS comet is currently considered one of the brightest objects in the sky. It ranks fourth among the observable celestial bodies.

At the top of the ranking is the C/2025 A6 (Lemmon) comet, which has also lost a significant amount of its brightness. The ZI/ATLAS comet was first detected on July 1, 2025.

Scientists have confirmed that its origin belongs to another star system. According to research, the comet is over 7.5 billion years old, making it one of the oldest objects in the universe.

Overall, the ZI/ATLAS comet holds special significance not only from a geophysical perspective but also from an astronomical historical point of view. In the coming weeks, its movement and brightness changes will be closely monitored by the scientific community with great interest.