On July 1, the Asteroid Terrestrial-impact Last Alert System (ATLAS) detected what was first believed to be an asteroid. As calculations for its orbit progressed, it was found to be from outside our solar system, only the third interstellar object ever detected.

[One] thing that astronomers discovered early on was that, rather than being an asteroid, the interstellar interloper dubbed 3I/ATLAS was a comet.

"It is doing things that we expect comets to do. It's producing the types of gasses that we see comets produce. It's got a coma and a tail now pointed in the expected direction," said James Wray, a professor at the Georgia Institute of Technology's School of Earth and Atmospheric Sciences. "I would say the short summary is it looks generally like a comet. But in detail, there are some intriguing differences from solar system comets."