95K views · 730 reactions | Observation of Comet ISON (C/2012 S1),...

A comet from another star system is flying through ours. The comet, named 3I/ATLAS, is only the third known interstellar object ever observed in our solar system. First spotted in July 2025 by the ATLAS telescope in Hawaii, it didn’t take long for astronomers to realize it wasn’t from here. Its speed and trajectory made it clear: this comet came from deep space. At its closest point to the Sun – called perihelion – 3I/ATLAS was hidden from Earth’s view, blocked by the Sun. But Mars was perfectly

48 reactions | • Observation of Comet 2I/Borisov in October 2019 10.3.23 • On 12 October 2019, the NASA/ESA Hubble Space Telescope observed Comet 2I/Borisov at a distance of approximately 420 million kilometres from Earth. The comet is believed to have arrived here from another planetary system elsewhere in our galaxy. • Credit: NASA, ESA, D. Jewitt (UCLA) | Astronomy Nation | Facebook