Scientists are surprised: The interstellar invader comet 3I/ATLAS has grown a tail!
This image is both a milestone in science and a source of amazement.
September 5, 2025, U.S. Space News report.
Astronomers have captured stunning images of the interstellar invader comet 3I/ATLAS growing a tail. Figures 1, 2, 3
This image was taken on August 27, 2025, by the Gemini Telescope at Cerro Pachón in Chile.
When comets like 3I/ATLAS approach the Sun, solar radiation heats the ice in their cores.
This causes the solid ice they carry to directly turn into gas, skipping the liquid stage, a process called "sublimation."
Then these gases are ejected from the comet, forming its unique halo or "coma" and characteristic tail.
3I/ATLAS moves against the backdrop of the night sky as seen by ground-based telescopes at the Las Campanas Observatory. Figure 4
Besides the aesthetic value of the image, the observations allow scientists to observe the wavelengths of light it emits, or its spectrum.
This is useful because different chemical substances emit and absorb light at their own characteristic wavelengths,
which means that the chemical composition of 3I/ATLAS leaves a "fingerprint" in the spectrum of its coma and tail.
This indicates that the dust particles have changed compared to previous Gemini images, and for the first time we have seen the chemical composition from the spectrum.
These new observations indicate that the chemical composition of 3I/ATLAS is similar to that of comets originating from our solar system.
"These observations provide an amazing view and key scientific data,"
said scientist Bryce Bolin: "Each interstellar comet is a messenger from another stellar system,
by studying their light and colors, we can begin to understand the diversity beyond our own world."
Original: www.toutiao.com/article/1842462386436108/
Statement: This article represents the views of the author.