"Called a 'Christmas Gift'... The Strange Comet Growing Darker [Reading Science]"

Leonard Comet Near Earth, Growing Darker
Speculated Causes Include Fragmentation or Ice Depletion

Leonard Comet. Photo by Space.com

[Asia Economy Reporter Kim Bong-su] The cosmic visitor 'Comet Leonard (C/2021 AI)', which is visiting Earth again after 70,000 years, is attracting attention due to its strange behavior. While typical comets brighten as they approach the Sun after passing Earth, Comet Leonard is instead losing brightness and becoming darker. Experts analyze that this is because it is disintegrating and disappearing or because the ice reflecting light has melted.

According to the space-specialized media Space.com on the 10th, Comet Leonard was first discovered heading toward Earth on January 3 of this year by the University of Arizona Observatory. From December this year to January next year, it will pass Earth and head toward the Sun, making ground observation possible. In particular, astronomers expected this comet, which approaches Earth just before Christmas, to emit the brightest light among those observed this year. Comets, composed of ice, dust, and gas, do not emit light themselves but melt as they approach the Sun, leaving beautiful light and long tails. However, most comets are overshadowed by the Sun’s light, making it difficult for ordinary amateurs to observe anything more than faint traces with telescopes.

However, Comet Leonard was expected to brighten further as it approached Earth closely earlier this month. Especially around 5:30 a.m. on the 4th of this month, just after the new moon when moonlight disappears, it was predicted that the comet could be observed with binoculars just above the eastern horizon. Also, two hours before sunrise on the 6th, it was expected that the comet with a long dust tail, which had become noticeably longer since early November, could be seen in the eastern sky. The closest approach to Earth will be on the 12th, with a maximum brightness magnitude forecasted at +4.3. This brightness is enough to be seen without optical aids under dark skies free from light pollution.

However, instead of getting brighter, Comet Leonard is currently becoming darker. Experts analyze that the comet may be entering a disintegration phase. Professor Quanzi Ye of the University of Maryland explained, "Comet Leonard should be getting brighter, so this is not good news," adding, "It means something is wrong, but the exact reason is not yet known. Comet Leonard may have already fragmented or started to fragment, or the ice that should melt and emit water vapor toward the Sun may have been completely depleted." He also said, "When observed on the morning of the 7th, the comet’s shape looked fine, but it was confirmed that it continued to darken," adding, "We need more time to understand the reason."

Meanwhile, Comet Leonard is analyzed to have come from the Oort Cloud, about 52 billion kilometers away from Earth. The Oort Cloud is a hypothetical collection of celestial bodies surrounding the solar system like a shell, known to consist of numerous icy bodies.