Scientists are eagerly anticipating the ROSETTA probe's next pass of Earth, because they know that something they don't know about might happen.  Probes passing by Earth to pick up a gravitational slingshot have been experiencing unexplained extra accelerations, and the reasons could reveal fundamental facts of existence – if we ever work them out.

The discrepancies are tiny, mere millimeters per second compared to the total value of many thousands of meters a second, but the thing about rocket scientists is they don't just wave their hand and go "Ah, it's just off a bit."  In fact the entire existence of rocket science as more than a field of explosion craters is based on that fact.  These minuscule movement changes have apparently randomly sped or slowed satellites for the last few decades, and some very smart people want to know why.

Don't dismiss this as some simple error in the calculations or hardware: experts have been picking this phenomena apart for over twenty years, and…

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