The Hubble Space Telescope has captured the best image of a high-speed comet visiting our solar system from another star.
NASA and the European Space Agency released the latest photos on Thursday.
Discovered last month by a telescope in Chile, the comet known as 3i-atlas is only the third known interstellar object to pass our way and poses no threat to Earth.
AP
Astronomers initially estimated the size of its icy core at several kilometers across, but Hubble observations narrowed it down to more than 3.5 miles. It could even be as small as 1,000 feet, scientists say, according to a new paper published in the astrophysical journal Letters.
The comet is hurtling at 130,000 mph, but will come closer to Mars than Earth, keeping a safe distance from both. It was 277 million kilometers away when it was photographed by Hubble a few weeks ago. The orbiting telescope revealed a teardrop-shaped dust plume around the core as well as traces of a dusty tail.
NASA previously said the comet would make its closest approach to the sun in late October, wandering between the orbits of Mars and Earth. The agency said the 3i/Atlas is expected to remain visible to telescopes through September, but it will happen too close to the sun to observe. It should reappear on the far side of the sun in early December, allowing renewed observations.
According to the Las Cumbres Observatory in Chile, the object is named “3i” because it is the third such interstellar object to be found, following 1i / ‘Oumuamu in 2017 and 2i / borisov in 2019.
“All three appear to be quite dark and red, reflecting only about 5 percent of the sunlight hitting them, which is similar in reflectivity to asphalt,” the observatory said last month. “Unlike 1i/’Oumuamu, 3i doesn’t change much in brightness as it rotates, indicating that it is more likely to be spherical.”
Los Cumbres Observatory created an animation of image data from its telescope as it tracked the new interstellar on July 4, 2025:
As scientists look at the object, some raise questions. Harvard professor Avi Loeb, who is the director of the Institute for Theory and Computation at the Harvard Smithsonian Center for Astrophysics, says it might actually be alien technology. He said many of his characteristics are not typical and his trajectory is “refined.”
“The object looks strange. It reflects a lot of sunlight,” he told “CBS Mornings Plus.” “Also, this object has some glow in front of it, not behind it. There is no tail, as is usually the case with comets.”
He advises that the best way to proceed is to collect as much scientific data as possible.
“Don’t assume anything, just monitor it and decide if it maneuvers, if it has artificial lights, if it looks like a technological object, and if it ends up being a comet, that is,” he said.
