A stray comet from another star system is swinging past Earth before racing back into the interstellar void
Sandeep K S
Dec 15, 2025
1 min read
Meet Comet 31/Atlas: An interstellar traveler making its third known passage through our solar system. Estimated to be up to 3.5 miles wide, it will approach Earth at 167 million miles on December 15, 2025, before heading past Jupiter in March and making its final departure in the mid-2030s.
It is one of the most famous questions in science, asked over lunch by physicist Enrico Fermi. With hundreds of billions of stars and billions of years, life should have emerged many times over. And yet, no signals. No visitors. No evidence of anyone at all.
The universe is 13 billion years old. Our galaxy alone contains hundreds of billions of stars, a significant proportion of which host planets. Many of those planets sit in the right temperature range for liquid water.
Here's a thought experiment that keeps planetary scientists awake at night. Strip every living thing from our planet—every bacterium, every blade of grass, every creature that has ever drawn breath—and ask a simple but profound question: Would Earth still be a world capable of supporting life?
The answer, it turns out, is yes. And that finding has enormous implications for how we search for life beyond our solar system. The problem is subtle but important.
Using the MeerKAT radio telescope, astronomers have discovered a natural "space laser" originating from a violently merging galaxy more than 8 billion light-years away.
When gas-rich galaxies collide, the impact compresses enormous reservoirs of gas. This violent cosmic crash can stimulate molecules—specifically hydroxyl (OH) molecules—causing them to emit incredibly bright, coherent radio waves.
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