Interstellar comet 3I/ATLAS emits radio signals and activates NASA alert

NASA activated intensive monitoring protocols after detecting unusual radio signals coming from comet 3I/ATLAS, the third interstellar object ever identified crossing the solar system. The discovery, made by an international network of radio telescopes, led Escritório of Coordenação of Defesa Planetária to expand surveillance of the cosmic visitor. The signals, although analyzed as a natural phenomenon, justify enhanced observation to ensure planetary safety and take advantage of a rare scientific opportunity.

The comet was identified on July 1, 2025 by the ATLAS system in Havaí and stands out for its hyperbolic orbit, indicating origin outside the solar system. Sua’s trajectory follows in the footsteps of ‘Oumuamua, discovered in 2017, and 2I/Borisov, identified in 2019. Agências spacecraft from around the world, including Agência Espacial Europeia (ESA), collaborate to collect data on the object and rule out any risk of collision.

Interstellar Visitor’s Características

3I/ATLAS has a nucleus with an estimated diameter of between 320 meters and 5.6 kilometers, surrounded by a coma of gas and dust that forms as the comet approaches Sol. Sua chemical composition, inferred by spectroscopy, reveals an abundance of elements unusual in local comets, reinforcing its external origin. The object passed approximately 10 million kilometers from Sol, allowing significant heating and release of material for analysis.

Diferente of previous interstellar visitors, 3I/ATLAS exhibits hybrid behavior with a well-defined coma and tail. Sua’s entry trajectory into the solar system was at a steep angle to the ecliptic plane, where most planets orbit. Astrônomos uses computer models to try to trace its route back to a possible stellar system of origin, a complex task due to gravitational uncertainties over millions of years of travel through interstellar space.

The mystery of captured radio signals

On October 24, 2025, the MeerKAT radio telescope, located at África of Sul, captured radio emissions at a frequency of 1.6 GHz. Esses signals were later confirmed by other observatories, generating intense debate about their origin. The scientists’ main hypothesis is that the signals are hydroxyl (OH) masers, a type of microwave emission that occurs naturally in comets when water molecules in their coma are dissociated by solar radiation.

The intensity and consistency of the 3I/ATLAS signals are stronger than expected, prompting further investigation. Pesquisadores rule out, for now, any artificial origin for the emissions. The analysis of the spectrum of the signals is consistent with known astrophysical processes, although the activity of 3I/ATLAS reinforces its nature as an atypical object of great value for the study of astrochemistry.

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Protocolos Planetary Defense Activated

• Elevação of the alert level for continuous monitoring of the comet.
• Alocação of more observation features, including Rede of Espaço Profundo (DSN).
• High-precision Rastreamento for detailed analysis of radio signals.
• International Colaboração between NASA, ESA and other global observatories.

NASA’s Escritório of Coordenação of Defesa Planetária raised the alert level, not because of imminent risk, but to allocate more observation resources. The agency plans a press conference to detail the findings and next steps. ESA is also actively involved, using its own tracking systems to provide an independent second opinion on the comet’s orbit.

Trajetória safe and approaching Terra

According to the most recent orbital calculations, comet 3I/ATLAS will make its closest approach to Terra on December 19, 2025. Nesse will pass at a safe distance of about 27 million kilometers, more than 70 times the distance between Terra and Lua. Portanto, there is absolutely no risk of impact with our planet. The unpredictable nature of comets, which can fragment or have their path altered by jets of gas, requires continued surveillance as a standard precautionary measure.

Oportunidade extraordinary scientific

The passage of 3I/ATLAS represents a unique opportunity for astronomers to study a fragment of another solar system up close. Telescópios like Very Large Telescope (VLT) in Chile and space telescopes are focused on deciphering the spectral signature of the light reflected by its coma and tail. Essa analysis allows you to identify molecules present such as water, carbon monoxide, cyanide and organic compounds that are building blocks of life.

The presence and proportion of these elements can indicate whether the stellar system of origin is similar to or radically different from ours. Observing how the object reacts to radiation and solar wind provides crucial data to improve models of the formation and evolution of comets, considered fossil remains from the creation of planetary systems. Monitoring teams will continue to follow 3I/ATLAS intensively during its journey out of the solar system, detecting changes in radio emission and possible fragmentation events.