Go to http://brilliant.org/DrBecky and sign up for free. The first 200 people that go to that link will get 20% off the annual premium subscription. In 2009 the IBEX satellite detected an excess of atoms reflected back from a particular spot at the edge of the solar system that originally came from the Sun. To this day this echo, dubbed the “IBEX ribbon” is unexplained. Could it be something to do with the Milky Way’s magnetic field? Or something more sinister that might affect future human exploration of the solar system?

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