The United Nations’ International Asteroid Alert Network is closely monitoring Comet 3I/ATLAS. Here’s why:

As the interstellar comet 3I/ATLAS prepares to make its closest approach to Earth on December 19th, it is being watched by space agencies as well as the United Nations.

The comet will come within about 167 million miles (270 million kilometers) of Earth and will be tracked by telescopes around the world to help astronomers pinpoint its location and make predictions about similar future objects.

The United Nations’ International Asteroid Warning Network (IAWN) is about halfway through its 3I/ATLAS observing campaign and plans to publish its findings in a peer-reviewed journal next year, James Bauer, IAWN’s Small Object Node principal investigator and research professor in the University of Maryland’s Department of Astronomy, told Live Science. The network is comprised of more than 80 observatories and citizen scientists around the world conducting active research on near-Earth objects such as comets and asteroids.

you may like

Bauer said NASA is coordinating the network’s observation campaign with IAWN, and 3I/ATLAS is the first interstellar object to be tracked since the campaign began in 2017 (notably, potentially The dangerous near-Earth asteroid Apophis has been observed by IAWN in 2020 and 2021, and a new campaign is expected between 2027 and 2029 as the asteroid makes an orbit (safe but close to Earth). )

“The idea behind these campaigns is actually to strengthen the technical capacity to measure the positions of asteroids and comets in the sky, which is called astrometry,” Bauer said of IAWN’s efforts. Researchers plan to test new astronomical measurement techniques to track 3I/ATLAS’s path, which could help determine how to send spacecraft to similar comets in the future.

“We want our community to use the latest and greatest technology,” Bauer said. (Bauer also serves as principal investigator for the Small Objects node of the NASA Planetary Data System, which archives, catalogs, and disseminates scientific data on comets, asteroids, and interplanetary dust.)

Tracking the “comet of comets”

IAWN had been planning such an observation campaign since October 2024, so 3I/ATLAS was first discovered in late June, a late but fortuitous arrival. Bauer said the interstellar comet’s upcoming approach matched well with the team’s planned observation schedule, and 3I/ATLAS seemed like a great fit because it can be observed by the network’s observatories and interest was high.

He pointed to challenges to accurately measuring a comet’s position, including changes in brightness, variations in coma, and fluctuations in the clouds of gas and dust that grow around the comet’s core and tail as it heats up as it approaches the sun. These features increase the comet’s apparent size and can make it difficult to locate it.

Fortunately, even though 3I/ATLAS originated outside the solar system, it exhibits classic comet behavior, making it almost a “comet of comets,” Bauer said. For example, it contains components such as water and carbon dioxide, which behave similarly to normal solar system comets.

Community interest is growing. At the kickoff of IAWN’s 3I/ATLAS campaign conference in October, citizen scientists, observatories large and small, and scientific organizations formed a record 171 campaign participants. A few days before Bauer’s interview with Live Science, 100 campaign participants attended a mid-campaign conference call on Dec. 9.

“We’ve been answering questions from the community, such as, ‘How do I use the tool? What is the appropriate format for observing and reporting observations?'” Bauer said.

He said he is grateful for the community’s time and interest, which is helping astronomers hone their ability to report the positions of objects in the sky, including “alertness” for other near-Earth asteroids and objects much closer to Earth.