Interstellar comet is making its closest approach to Earth

 

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Interstellar comet is making its closest approach to Earth

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  Interstellar comet is making its closest approach to Earth this week

  December 15, 2025 / 1:37 PM EST / CBS/AP

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  A stray comet from another star swings past Earth this week in one last hurrah before racing back toward interstellar space.

  Discovered over the summer, the comet known as 3I/Atlas will pass within 167 million miles (269 million kilometers) of our planet on Friday, the closest it gets on its grand tour of the solar system.

  NASA continues to aim its space telescopes at the visiting ice ball, estimated to be between 1,444 feet and 3.5 miles in size. But it's fading as it exits, so now's the time for backyard astronomers to catch it in the night sky with their telescopes.

  The comet will come much closer to Jupiter in March, zipping within 33 million miles. It will be the mid-2030s before it reaches interstellar space, never to return, said Paul Chodas, director of NASA's Center for Near Earth Object Studies.

  It's the third known interstellar object to cut through our solar system. Interstellar comets like 3I/Atlas originate in star systems elsewhere in the Milky Way, while home-grown comets like Halley's hail from the icy fringes of our solar system.

  A telescope in Hawaii discovered the first confirmed interstellar visitor in 2017. Two years later, an interstellar comet was spotted by a Crimean amateur astronomer. NASA's sky-surveying Atlas telescope in Chile spotted comet 3I/Atlas in July while prowling for potentially dangerous asteroids.

  Scientists believe the latest interloping comet, also harmless, may have originated in a star system much older than ours, making it a tantalizing target.

  NASA has released several images of 3I/Atlas, including one last month showing it move through space about 180 million miles from Earth.

  

  This image, provided by NASA, shows the interstellar comet 3I/Atlas captured by the Hubble Space Telescope on Nov. 30, 2025, about 178 million miles from Earth.  NASA, ESA, STScI, D. Jewitt (UCLA), M.-T. Hui (Shanghai Astronomical Observatory), J. DePasquale (STScI) via AP

  In October, images taken by two Mars orbiters showed a bright, fuzzy white dot of the comet, appearing to move against a backdrop of distant stars as it was about 18,641,135 miles away from Mars.

  In September, an image showed the growing tail of 3I/ATLAS streaking across our solar system. 

  Harvard scientist Ari Loeb, who believes he's seen proof of alien life before, said he suspected the object may instead have alien origins. 

  "We should put all possibilities on the table that it's a rock, a comet, or something else until we get the evidence, the data that will tell us what it is," Loeb said in an interview with CBS Boston.