NASA press conference shares new data on Interstellar comet 3I/ATLAS

NASA held a press conference on November 19, 2025, to release new data on the interstellar object 3I/ATLAS following delays caused by the U.S. government shutdown.

Harvard Professor Avi Loeb attended and reported that the agency confirmed 3I/ATLAS is considered a natural comet. Loeb noted,

“NASA will repeat the official mantra that 3I/ATLAS is a natural comet and that they were unable to process the data until this week because of the government shutdown.”

The press conference provided images and measurements from multiple telescopes, including HiRISE, MAVEN, Hubble, Webb and SPHEREx, without offering significant revisions to previous findings.

New findings presented on 3I/ATLAS during the NASA press conference

HiRISE imaging and spectroscopic observations

The HiRISE camera aboard the Mars Reconnaissance Orbiter captured an image of 3I/ATLAS on October 3, 2025, at a spatial resolution of 30 kilometers per pixel.

Loeb explained that due to spacecraft "jitter" during the observation period, the light from 3I/ATLAS is smeared across several pixels.

This image presents a diffuse light signature consistent with previous observations. In addition, MAVEN detected hydrogen in the ultraviolet spectrum, adding minor new data on the comet’s composition.

Images from Hubble, Webb and SPHEREx are also available, providing complementary or fuzzier data to HiRISE. Loeb emphasized the importance of quantitative analysis, stating,

“In the coming days I will analyze this data quantitatively to extract the most important information out of it.”

Characteristics and behavior of 3I/ATLAS

NASA officials reported that 3I/ATLAS exhibits behaviors typical of comets, such as shedding gas and dust and responding to gravitational forces. Loeb noted that the press conference emphasized this perspective, stating,

“3I/ATLAS does what comets do, namely shed gas and dust and responds to gravity.”

The spacecraft collected measurements of surface materials, including dust and ices of CO2, CO and H2O.

Loeb indicated that NASA representatives did not discuss the 12 unusual aspects of 3I/ATLAS, including its comparatively large mass and the alignment of its trajectory with the plane of the planets.

Loeb cited prior work, explaining that the comet’s mass is a million times larger than that of 1I/`Oumuamua and a thousand times larger than that of 2I/Borisov, highlighting its "mass anomaly."

Recent observations and future measurements

After 3I/ATLAS’s closest approach to the Sun on October 29, 2025, amateur astronomers captured images showing tightly collimated jets extending approximately a million kilometers. Loeb highlighted the data, stating,

“These images show tightly collimated jets pointing towards and away from the Sun and reaching distances of order a million kilometers.”

Upcoming observations from larger ground-based telescopes, along with Hubble and Webb instruments, are expected to measure the jets’ composition, speed and mass loading rate.

These measurements aim to determine whether the jets are produced by natural sublimation or other processes.

Additional data collection

Loeb also suggested monitoring for fragments or accompanying objects associated with 3I/ATLAS.

He recommended that NASA and associated observatories examine data from Mars rovers, orbiters, and Galileo Project instruments for potential secondary objects. Loeb stated,

“Related data from Mars rovers or orbiters or from Earth-based NASA satellites or Galileo Project observatories could reveal fragments from an iceberg that broke up or mini-probes released by a technological mothership.”

This ongoing analysis aims to expand the dataset available for understanding interstellar objects.

Stay tuned for more updates.