3 Visitors From Another Star (The Last Is Older Than Earth)

Three times, something has flown into our solar system from another star, and the third interstellar visitor, 3I/ATLAS, may be older than the Earth itself. Here's what 'Oumuamua, Borisov and 3I/ATLAS really were, and why the next one could arrive any month. 'Oumuamua (2017) had no tail and no visible gas, yet something pushed it away from the Sun faster than gravity allows. Was it a hidden-gas comet, a shard of exotic ice, or (as one Harvard team suggested) a light sail? 2I/Borisov (2019), found by an amateur astronomer with a homemade telescope, turned out to carry more carbon monoxide than water. And 3I/ATLAS (2025), the fastest comet ever recorded, was studied by Hubble, the James Webb Space Telescope, the Parker Solar Probe and Mars orbiters, revealing a CO2-rich coma, methane and glassy interstellar dust. Put side by side, these three interstellar objects show that every planetary system builds its comets from a different recipe. With the Vera Rubin Observatory now scanning the sky and ESA's Comet Interceptor in preparation, the fourth visitor may not be far away. 0:00 Three visitors from another star 0:34 How do you know a rock isn't from here? 1:25 The scout from Hawaii 2:38 No tail, no gas, but something pushed it 3:39 Three explanations, one very controversial 5:53 Found in a backyard in Crimea 7:22 The fastest visitor ever recorded 8:50 Answers, or new questions? 10:00 Three visitors, three recipes 10:18 The next one is already on its way Sources: Micheli et al. (2018), Non-gravitational acceleration in the trajectory of 1I/2017 U1 ('Oumuamua), Nature: https://www.nature.com/articles/s4158... 'Oumuamua ISSI Team (2019), The natural history of 'Oumuamua, Nature Astronomy: https://arxiv.org/abs/1907.01910 Jewitt & Seligman (2022), The Interstellar Interlopers (review): https://arxiv.org/abs/2209.08182 Bialy & Loeb (2018), Could Solar Radiation Pressure Explain 'Oumuamua's Peculiar Acceleration?, ApJL Jackson & Desch (2021), 1I/'Oumuamua as an N2 ice fragment of an exo-Pluto surface, JGR Planets Bergner & Seligman (2023), Acceleration of 1I/'Oumuamua from radiolytically produced H2 in H2O ice, Nature Guzik et al. (2019), Initial characterization of interstellar comet 2I/Borisov, Nature Astronomy: https://www.nature.com/articles/s4155... Bodewits et al. (2020), The carbon monoxide-rich interstellar comet 2I/Borisov, Nature Astronomy: https://www.nature.com/articles/s4155... Seligman et al. (2025), Discovery and Preliminary Characterization of a Third Interstellar Object: 3I/ATLAS, ApJL: https://iopscience.iop.org/article/10... NASA, 3I/ATLAS Facts and FAQs: https://science.nasa.gov/solar-system... NASA, Comet 3I/ATLAS News (Webb, Hubble, Parker, SPHEREx): https://science.nasa.gov/solar-system... ESA, Comet 3I/ATLAS FAQ: https://www.esa.int/Science_Explorati... Minor Planet Center, 3I/ATLAS orbit: https://minorplanetcenter.net/db_sear... Caltech/phys.org (Apr 2026), Methane emerges from interstellar comet 3I/ATLAS: https://phys.org/news/2026-04-methane... JWST/MIRI amorphous silicates in 3I/ATLAS (2026): https://arxiv.org/abs/2606.27535 ESA/Hubble heic2509, Hubble makes size estimate of interstellar comet: https://esahubble.org/news/heic2509/ Music (Kevin MacLeod, incompetech.com, licensed under Creative Commons: By Attribution 4.0, http://creativecommons.org/licenses/b... "Lightless Dawn", "Dark Fog", "Echoes of Time v2", "Ossuary 6 - Air" Images: NASA, ESA, STScI, JPL-Caltech, GSFC and ESA/Hubble. NASA imagery is used under NASA's media guidelines; no endorsement implied. ESA/Hubble images are CC BY 4.0. Title cards and diagrams are our own. Some images are artist's concepts, not photographs. Disclosure: narration is AI-generated (synthetic voice). The script was researched, written and fact-checked for this channel. Watch next: The Wow! Signal: 72 Seconds We Still Can't Explain:    • The Wow! Signal: 72 Seconds We Still Can't...   #space #astronomy #interstellar