On Aug. 27, researchers using a Gemini Observatory telescope in Chile captured an image showing interstellar comet 3I/ATLAS developing a broader coma and a tail roughly 1/200th of a degree across as it moves inward through the solar system; NASA has said the object poses no danger to Earth.
Key Takeaways
- Image taken Aug. 27 by the International Gemini Observatory (Chile) shows an expanding coma and tail around comet 3I/ATLAS.
- The tail spans about 1/200th of a degree in the sky and points away from the sun.
- The session was part of a public outreach event that allowed students to work with astronomers remotely.
- Spectra collected during the session aim to reveal the comet’s composition and how it changes near the sun.
- 3I/ATLAS is the third confirmed interstellar object to visit our system, after 1I/’Oumuamua (2017) and 2I/Borisov (2019).
- NASA expects the comet to reach perihelion in late October, passing between the orbits of Mars and Earth, and to be visible through September before it moves too close to the Sun.
Verified Facts
The Gemini image, released by NOIRLab, shows a pronounced coma—a cloud of dust and gas around the nucleus—and a tail that appears more extended than in earlier photos. Astronomers say this indicates increased activity as 3I/ATLAS warms while approaching the inner solar system.
Earlier observations in early August included Hubble Space Telescope images taken when the comet was about 277 million miles from Earth. Those images, and the new Gemini exposure, together track the object’s changing appearance over weeks.
The Aug. 27 observing session was organized as an outreach event that let students and members of the public remotely join astronomers in the control room. In addition to imaging, participants gathered spectral data—measurements of light at different wavelengths—which help identify molecules and dust in the coma.
The visible tail aligns roughly opposite the sun, as expected when solar radiation and the solar wind push dust and gas away from the comet’s nucleus. Astronomers measured the tail’s angular length at about one two-hundredth of a degree, a small but measurable extent in the sky.
Context & Impact
Interstellar visitors are rare. Only two prior objects have been confirmed as extrasolar: 1I/’Oumuamua in 2017 and 2I/Borisov in 2019. Each provided unique opportunities to sample material formed around other stars.
Because 3I/ATLAS will pass between Mars and Earth on its inbound leg and reach perihelion in late October, scientists have a limited window to collect spectra and imagery. Those data can reveal volatile content, dust properties, and how an interstellar nucleus reacts to solar heating.
Opportunities for follow-up include ground-based spectroscopy across optical and infrared bands and imaging from space telescopes when geometry allows. Results could inform models of planetesimal formation in other stellar systems.
Near-term observational timeline
- Visible through September from some locations.
- Becomes too close to the sun to observe directly as it approaches perihelion in late October.
- Expected to reappear on the far side of the sun in early December.
“This image is both a scientific milestone and a source of wonder,”
Karen Meech, University of Hawai’i Institute for Astronomy
Unconfirmed
- Suggestions that 3I/ATLAS is artificial or contains alien technology are speculative; there is no evidence supporting such claims.
Bottom Line
The new Gemini Observatory image documents a measurable increase in activity from the interstellar comet 3I/ATLAS and highlights a narrow window for scientists to collect spectra and images before the object passes perihelion. Continued observations over the next months will help astronomers compare this visitor’s composition and behavior with comets formed in our own solar system.