Short Wave

Hot galaxies alert!

January 9, 2026

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  • A galaxy cluster formed only 1.8 billion years after the universe began was found to be unexpectedly hot, challenging current theories on how these structures evolve. 
  • Elephants possess an olfactory advantage over humans and dogs, using their sense of smell to accurately discriminate between different quantities of food in a maze setting. 
  • Painted lady butterflies in the Northern and Southern hemispheres follow opposite migration paths, a phenomenon linked to a large, flipped segment of DNA containing migration-related genes acting as a genetic barrier at the equator. 

Segments

Hot Galaxy Cluster Discovery
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(00:00:34)
  • Key Takeaway: A galaxy cluster formed 12 billion years ago was found to be hotter than the sun’s surface, contradicting expectations for young clusters.
  • Summary: Galaxy clusters are collections of galaxies, like the Local Group containing the Milky Way. Current theories suggest younger clusters should be relatively cool, but one formed about 12 billion years ago was detected as extremely hot. This finding, which includes three active galaxies with supermassive black holes, forces a rethinking of how large structures form early in the universe.
Elephant Sniffing Abilities Tested
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(00:04:08)
  • Key Takeaway: Elephants can use their superior sense of smell (powered by nearly 2,000 olfactory genes) to reliably choose paths leading to greater quantities of food.
  • Summary: Elephants possess five times more olfactory genes than humans, enabling remarkable scent discrimination. In a maze test, captive elephants consistently chose the path with more food unless the difference was less than 600 grams. Understanding this ability could lead to methods, like using bad odors, to protect crops from elephants.
Butterfly Migration Genetics Revealed
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(00:06:25)
  • Key Takeaway: Painted lady butterflies in opposite hemispheres follow opposing migration paths, a divergence linked to a large, flipped segment of DNA affecting migration genes.
  • Summary: The painted lady butterfly undertakes the longest migration of any butterfly species, but northern and southern populations migrate in opposite directions, with the equator acting as a barrier. Researchers found that a large chunk of DNA in southern hemisphere butterflies was completely flipped compared to northern ones, containing genes involved in migration. This genetic divergence offers a lens into how a single species can split across a migration barrier.