Astrophysicists are rejecting recent claims made by Harvard astronomer Avi Loeb that comet 3I/ATLAS could be an alien spacecraft. The comet, which was detected in July 2023 by the Asteroid Terrestrial-impact Last Alert System (ATLAS) in Chile, has sparked a wave of speculation on social media after Loeb”s comments.
According to experts, such theories are unfounded. Michael Kueppers, an astrophysicist with the European Space Agency (ESA), stated that there is no evidence to suggest that 3I/ATLAS is anything other than an interstellar celestial body. He highlighted its unusual chemical characteristics, which remain explainable within the realm of scientific understanding. Kueppers asserted, “If we were to find other civilizations, comets would not be the way to do it.”
The uniqueness of 3I/ATLAS lies in its origin; it is believed to have formed in a different region of the galaxy, rather than within our solar system. While the exact location of its origin remains unknown, astronomers recognize it as an interstellar traveler—essentially a fragment from another planetary system that has spent billions of years in space and is now crossing through ours.
Another point of interest for scientists is the comet”s peculiar composition. Unlike most solar system comets, which primarily consist of frozen water and various ices, 3I/ATLAS has a significantly higher ratio of carbon dioxide (CO2) relative to water. Kueppers noted that this could imply it formed in a colder environment than its original system, where volatile elements could accumulate at lower temperatures, or it may be a result of its journey through space.
Additionally, the comet contains a notable amount of metallic nickel. Although the reasons for this discovery are not fully understood, Kueppers suggested that it might provide insights into the diversity of other planetary systems. He remarked, “These objects allow us to learn firsthand what stellar systems outside our own are like.”
In contrast to the limited and distant images captured by telescopes, interstellar objects like 3I/ATLAS carry physical materials from their ancient worlds. It is estimated that this comet could be around 3 billion years older than our solar system. To date, only two other interstellar visitors have been identified: 1I/”Oumuamua in 2017 and 2I/Borisov in 2019, each contributing further knowledge about the formation of planets and comets around other stars.
Loeb has recently speculated that 3I/ATLAS may execute a navigational maneuver as it approaches its closest point to the Sun at the end of October, positing that it might release probes toward planets orbiting the Sun as if it were an alien spacecraft. However, Elena Manjavacas, an astronomer at the Space Telescope Science Institute in Maryland, dismissed any speculation linking 3I/ATLAS to extraterrestrial technology. She stated that for such ideas to hold any merit, several extraordinary conditions would need to be met: the existence of life elsewhere in the universe, that this life is intelligent, that it has developed a civilization with technological capabilities similar to a space agency, and that it is aware of Earth and has decided to send a spacecraft here.
Manjavacas emphasized that the likelihood of all these conditions occurring simultaneously is virtually nonexistent. Instead, she concurred with Kueppers that the scientific explanation of the comet being an interstellar body is significantly simpler and aligns with expectations for an object traveling from cold, distant regions of the galaxy. “It is far more probable that we are observing a peculiar comet, not an extraterrestrial spacecraft. In fact, that would be the most unlikely possibility of all,” she stated.
Loeb has previously argued that the elongated shape of “Oumuamua could be indicative of an extraterrestrial solar sail or remnants of an artifact created by an alien civilization. He based this hypothesis on the observation that “Oumuamua, being the first of its kind and having a lack of a comet”s tail, appeared unusually bright, ideas he elaborated on in a popular science book that has received criticism from the scientific community.
Recently, the announcement of an international observation campaign for 3I/ATLAS, promoted by the International Asteroid Warning Network (IAWN), coincided with Loeb”s assertions. The overlap of these announcements led to a surge of bizarre theories on social media, with some claiming, without any evidence, that NASA had activated a supposed planetary defense protocol in response to the interstellar object”s visit.
The campaign, scheduled to run from November 27 to January 27, is a routine scientific initiative aimed at studying objects with unusual trajectories or compositions. According to IAWN, a network coordinated by the United Nations comprising space agencies and observatories worldwide, the goal is to improve the accuracy of calculations regarding the comet”s position, speed, and chemical composition. This is not a defensive maneuver but rather an opportunity to deepen our understanding of a unique visitor.
“First and foremost, we must listen to scientists,” Manjavacas stated. “We base our understanding on evidence, not desires. The notion that an intelligent civilization has sent a spacecraft here may be appealing, but it is infinitely improbable.” Nevertheless, she acknowledged the interest that this phenomenon generates. “What is essential is that astronomy continues to fascinate people. Not because of extraterrestrials, but because it helps us understand our place in the universe.”
