Archive for March 12th, 2008


Wednesday, March 12th, 2008


“Mottenfrassl oder Quantenflunktuationen?”, artwork by Fin D. Dvorak (slight modifications of a physics congress images)

Just an update on the pioneer effect and a similar sofar unexplained effect called fly-by anomaly. The fly-by anomaly occurs sometimes in socalled gravitational slingshots . A gravitational slingshot manoeuvre means to choose a spacecraft trajectory, which passes in such a way by a planet or a sun that the spacecraft experiences acceleration or deceleration. (Here a nice animation).

The fly-by anomaly says that in certain slingshot manoeuvres around the earth the corresponding space craft experienced an acceleration, which could not be accounted for by standard computations. The deviaton is small, but persistent. However the computations are quite complicated and it is already astonishing how precise researchers can nowadays predict spacecraft trajectories. And there better be no error in the computations! Just imagine if someone would for example confuse the various meridians…then in such a case a poor spacecraft could of course be burned by the sun before it ever reaches it. :)

Jet Propulsion Laboratory astronomer John Anderson gave an interview to

“I am feeling both humble and perplexed by this,” said Anderson, who is now working as a retiree. “There is something very strange going on with spacecraft motions. We have no convincing explanation for either the Pioneer anomaly or the flyby anomaly.”

and to the planetary society he said:

“It was time,” he said, “to tell people that there was a problem with earth flybys.” If the engineers at JPl couldn’t’ explain the effect, perhaps the broader scientific community could come up with an explanation.”

->article by Anderson in Physical Review letters

->talk on pioneer anomaly and fly-by effect at the Physikalisches Kolloquium, OvG–Universit¨t Magdeburg, 17.1.2007