The Universe is bizarre. Space probes get unexpected boost.

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This isn't an isolated case. During Earth flybys by the space probes NEAR, Cassini-Huygens and Rosetta, all experienced a unexplained boosts of 13 mm/s, 0.11 mm/s and 2 mm/s respectively. Once technical faults, observational errors, radiation pressure, magnetic instabilities and electrical charge build-up could be ruled out, focus is beginning to turn to more exotic explanations.

A recent study by Magic McCulloch suggests that "Unruh radiation" may be the culprit. The Unruh effect, put simply, suggests that accelerating bodies experience a type of electromagnetic radiation. At very low acceleration, the wavelength emitted will be so large that a whole wavelength will be longer than the dimensions of the Universe (otherwise known as the Hubble Distance). Low acceleration would therefore generate waves that have no effect on the body. However, should the accelerating body (i.e. Galileo getting accelerated by Earth's gravity during the 1990 flyby) slowly exceed an acceleration threshold, the Unruh radiation will decrease in wavelength (smaller than the Hubble Distance), causing a tiny, but measurable "boost" to its increasing velocity.

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