An interstellar comet 3l/ATLAS, the 3rd and fastest of its kind to be observed passing through earth’s solar system, was detected on July 1st 2025. The first such comet to be detected was 1l/Oumuamua in 2017, the 2nd was 2l/Borisov in 2019. Interstellar comets are incredibly fast and can easily pass through earth’s solar system undetected. It is difficult to estimate how many of these objects race through in a given year. Despite the fact that the detected 3l/ATLAS is huge, with a 3-mile (5km) diameter, its nucleus is apparently not visible to the Hubble telescope which made the discovery. The expectation therefore is that the more powerful Rubin telescope which recently came online at the Rubin Observatory in Chile will be able to detect many of these racing objects in the coming years. In a 2022 paper, Hoover et al. estimated that the Rubin Telescope will detect between 0.9-1.9 interstellar objects every year. It notes that these are lower limits which will be revised when there is more data. https://arxiv.org/pdf/2109.10406 A 2023 paper by Ezell and Loeb expects the Rubin Telescope to detect one small interstellar object, < 50 m in diameter, every one to two years. https://arxiv.org/pdf/2303.14766 Another 2023 paper, this time by Marceta and Seligman, used a simulated suite of interstellar objects to estimate that the Rubin Telescope should detect up to 70 interstellar objects per year. @ researchgate.net “Synthetic Detections of Interstellar Objects with the Rubin Observatory Legacy Survey of Space and Time” (Credit space.com/hubble/NASA/RubinObs/SLAC)