NASA 公布多源观测数据显示 3I/ATLAS 为彗星而非外星技术，结束数周传言。SOHO 在约 3.58 亿公里距离上于 10 月 15–26 日意外捕获其影像；MRO 在约 2900 万公里距离取得迄今最清晰近照，显示受日照加热后喷发的典型尘埃云；STEREO 在 9 月 11 日至 10 月 25 日间通过多曝光叠加确认其呈弥散亮球状；MAVEN 的紫外光观测捕捉到氢信号左侧为彗星特征；PUNCH 则在 9 月 28 日至 10 月 10 日期间连续成像其彗尾结构。所有数据将公开供研究者检视。

NASA 强调 3I/ATLAS 具备典型彗星的光度分布、喷发物质与气体成分特征，符合此前两例星际天体（1I/‘Oumuamua 与 2I/Borisov）的跨星系轨迹模式。影像从红外到伽马射线多波段覆盖，使其物理性质与轨道活动得以全面确认。此次资料发布因美国政府停摆延宕，属“非关键业务”复工后的首个重大科学说明。

3I/ATLAS 将于 2025 年 12 月 19 日以约 2.67 亿公里距离掠过地球，相当于约月地距离的 700 倍、约地日距离的 1.8 倍，对地球无任何影响。全球空间机构预计在其后续轨迹上持续开展额外观测，以获取这第三个已确认星际天体的更多结构与成分信息。

NASA released multi-mission data confirming that 3I/ATLAS is a comet rather than alien technology, ending weeks of speculation. SOHO unexpectedly captured it at roughly 358 million kilometers between October 15–26; MRO obtained the closest high-resolution image at about 29 million kilometers, showing dust outgassing as it neared the sun. STEREO stacked exposures from September 11 to October 25 to reveal a bright diffuse orb; MAVEN’s ultraviolet data isolated the comet’s hydrogen signature; and PUNCH recorded the tail from September 28 to October 10. All datasets will be publicly accessible.

NASA stated that 3I/ATLAS exhibits standard cometary luminosity patterns, dust emissions, and gaseous features, consistent with prior interstellar objects 1I/‘Oumuamua and 2I/Borisov. Multi-spectrum observations—from infrared to gamma-ray—clarify its physical behavior and confirm its interstellar trajectory. The release marks NASA’s first major scientific briefing after nonessential operations restarted following the US government shutdown.

3I/ATLAS will pass Earth on December 19, 2025 at about 267 million kilometers, roughly 700 lunar distances and 1.8 times the Earth–sun separation, posing no risk. Additional observation campaigns from NASA and other agencies are planned to further study the third confirmed interstellar object.