Our Sun Is Moving Slower Than Thought

Our Sun Is Moving Slower Than Thought

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The sun is moving through the Milky Way slower than previously thought, according to new data from a NASA spacecraft. From its orbit around Earth, the Interstellar Boundary Explorer (IBEX) satellite measured the speeds of interstellar particles entering at the fringes of our solar system, 9 billion miles from the sun.

Plugging the new data into computer models, the IBEX team calculates that the sun is moving at about 52,000 miles an hour—about 7,000 miles slower than thought. The discovery suggests that the protective boundary separating our solar system from the rest of the galaxy is missing a bow shock, a major structural component thought to control the influx of high-energy cosmic rays.