How Giant Planets Kept Their Rapid Spin ⚡ экспресс
Scientists measured the rotation speeds of distant giant planets and brown dwarfs (failed stars). It turned out that planets spin faster than similar-mass brown dwarfs—it's like comparing a swift spinning top to a slow heavy flywheel. Perhaps the difference is linked to how they were born: for planets, the braking disk around them was weaker. Think about it: what governs the cosmic dance of giants?
Using the Keck telescope and spectroscopy (light analysis that reveals rotation speed), astronomers measured 32 objects: from giant planets to brown dwarfs—bodies heavier than planets but lighter than stars that never ignited.
Giant planets spin almost at the breakup limit: their gaseous cocoon at birth barely braked them, like ice under a spinning top. Brown dwarfs, however, lost spin quickly—their disk acted like sand. What's more, dwarfs bound to stars braked more than solitary ones; planets spin equally regardless of companionship.
Surprise: objects with masses 5–40 Jupiters kept more spin than heavier ones (40–100 Jupiters). It seems that during formation, crossing some threshold triggers strong braking. Jupiter with its 10-hour day is just a modest example: many giant planets spin even faster, teetering on the edge of self-destruction.
🎯 A day on Jupiter lasts only 10 hours—faster than any other planet in the Solar System.