An interstellar comet named 3I/ATLAS is set to make its closest approach to Earth on November 3, 2023, coming within approximately 167 million miles (270 million kilometers) of our planet. This remarkable celestial object, first identified in July as it traversed our solar system, is now departing our vicinity, but not before astronomers capture stunning new images during its approach.
The comet will not be visible to the naked eye, and the best viewing opportunities have already passed. Those interested in observing 3I/ATLAS will require a telescope of at least 8 inches (20 centimeters) to see it. The Virtual Telescope Project plans to provide a livestream of the comet at 04:00 UTC on Saturday, November 4, which corresponds to 11:00 p.m. ET on Friday. This event comes after cloud cover thwarted an earlier streaming attempt, according to Gianluca Masi, an astronomer at the Bellatrix Astronomical Observatory in Italy.
Scientific Insights from 3I/ATLAS
Astronomers have closely monitored 3I/ATLAS since its initial discovery, using powerful tools like the Hubble Space Telescope and the James Webb Space Telescope. These observations are crucial for understanding the comet’s origin and composition. As it approaches the sun, the comet releases gas and dust, potentially revealing vital information about the materials that formed it.
Comets are often described as “dirty snowballs,” composed of ice, dust, and rock. When these celestial bodies near stars, the heat causes them to release gas, forming their characteristic tails. Seligman, a cometary scientist, highlights the significance of studying the volatiles released as 3I/ATLAS nears the sun. He notes, “When it gets closest to the sun, you get the most holistic view of the nucleus possible.”
Research indicates that 3I/ATLAS is estimated to be between 3 billion and 11 billion years old. In comparison, our solar system is approximately 4.6 billion years old. Observations from various missions have detected crucial compounds such as carbon dioxide, water, and carbon monoxide emanating from the comet, furthering our understanding of its ancient origins.
Future Observations and Discoveries
While 3I/ATLAS faded from view for ground-based telescopes in October, it continued to be tracked by missions like PUNCH and SOHO. The comet made its closest approach to Mars on October 3, 2023, coming within 18.6 million miles (30 million kilometers) of the planet. Although a government shutdown has limited data sharing from NASA missions since October 1, the European Space Agency’s Mars Express and ExoMars Trace Gas Orbiter captured images of the comet, albeit as a faint dot.
Looking ahead, the ESA’s Jupiter Icy Moons Explorer is set to observe 3I/ATLAS in November, employing multiple instruments to gather data. However, results from this mission may not be available until February due to the data transmission rate.
A notable breakthrough in the study of 3I/ATLAS occurred when Japan’s X-Ray Imaging and Spectroscopy Mission (XRISM) successfully detected X-rays emitted from the comet. This marks a significant discovery, as no X-rays were recorded from previous interstellar comets that passed through our solar system in 2017 and 2019. The XRISM observed 3I/ATLAS for 17 hours, capturing X-rays extending up to 248,000 miles (400,000 kilometers) from the comet’s nucleus.
The findings suggest that interactions between the gases released by the comet and solar wind may be responsible for the X-ray emissions. This could provide further insights into the composition of 3I/ATLAS and its similarities or differences compared to comets found within our solar system.
As the comet continues its journey through the solar system, astronomers remain eager to gather as much data as possible. “We’ve got several more months to observe it,” Seligman remarked. “And there’s going to be amazing science that comes out.” The ongoing exploration of 3I/ATLAS promises to deepen our understanding of these fascinating celestial travelers, offering a glimpse into the mysteries of the universe beyond our solar system.
