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24 April 2014 11:45 am ,
Vol. 344 ,
Major climate data sets have underestimated the rate of global warming in the last 15 years owing largely to poor data...
The tsetse fly is best known as the vector for the trypanosome parasites that cause sleeping sickness and a disease in...
The National Institutes of Health is revising its "two strikes" rule, which allowed researchers only one chance to...
By stabilizing the components of retromers, molecular complexes that act like recycling bins in cells, a recently...
Fossil fuels power modern society by generating heat, but much of that heat is wasted. Semiconductor devices called...
Researchers are gaining insights into what made Supertyphoon Haiyan so powerful and devastating through post-storm...
Millions around the world got a first-hand look at what it was like to be in Tacloban while it was pummeled by...
- 24 April 2014 11:45 am , Vol. 344 , #6182
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ScienceShot: Anatomy of an Odd Asteroid
5 February 2014 6:00 am
The oddly shaped, near-Earth asteroid 25143 Itokawa just got a lot weirder. When researchers analyzed how the object’s brightness changed over the course of 10 short intervals between 2001 and 2013, as measured by Earth-based telescopes, they found that the 535-meter-long cosmic peanut (inset) wasn’t rotating as expected. A detailed analysis suggested that Itokawa’s center of mass (about which the asteroid rotates) was 21 meters closer to the smaller end of the peanut than expected—a sign that the smaller end of the body, for whatever reason, is denser than the larger end. Although a shift of 21 meters doesn’t sound like much, that disparity suggests that the smaller end of the asteroid is more than 1.6 times as dense as the plumper end (main image), the researchers report today in Astronomy & Astrophysics. Previously, some researchers have proposed that Itokawa is actually two asteroids in contact with one another, a scenario strongly supported by the new results, the team contends. It’s not clear whether the odd configuration results from the merger of a two-asteroid system or merely clumps of material that fell back together after a larger asteroid was blasted apart by an immense collision. Further analyses may yield an answer, the researchers say, and they also may provide insights into how asteroids and other bodies formed during earlier days of the solar system. One more oddity revealed by the new study: Due to the peculiar shape and weight distribution of the asteroid and irregularities in the way that heat is radiated into space, the rate at which Itokawa spins is accelerating, making it rotate about 45 milliseconds faster with each passing Earth year.