The fly-by anomalies are one of the outstanding puzzles in modern physics. Various spacecraft that have flown past Earth on their way to other parts of the Solar System, seem to have undergone a step-like change in velocity at their point of closest approach. The question is why.
Last year, we looked at an idea from Stephen Adler at Princeton University, that suggested the change in velocity could caused by collisions between the spacecraft and particles of dark matter. Adler even calculated the kind of distribution of dark matter particles that would explain the observed changes in velocity–a kind of halo of them around Earth.
Part of the puzzle is that some spacecraft seem to experience an acceleration while others a deceleration. But Adler has worked this out too. Apparently, a certain distribution of two kinds of dark matter particle could explain this.
Now he’s back with an idea that could settle the matter. He points out that when one thing bangs into another, some of the kinetic energy is dissipated as heat. There’ s no reason to think that that won’t be just as true of collisions between ordinary matter and its dark cousin. So Adler’s suggestion is to measure the temperature of spacecraft passing through the region of dark matter that his model says should surround Earth.
That can be done it two ways. The first is to send a spacecraft up that is specifically designed to measure any change in temperature. That’s expensive and time consuming.
The second and much easier approach is to mine the historical record for evidence that earlier satellites or spacecraft have heated up unexpectedly.
That’s a call to action (as Obama might say). The first evidence that dark matter not only exists but is smashing into our spacecraft would be valuable new physics indeed.
There are other explanations for the fly-by anomalies, however (my favourite). Not least of these is the possibility that the anomalies are artifacts of the current orbital data fitting techniques.
I know what I’m rooting for.
Ref: arxiv.org/abs/0910.1564: Spacecraft Calorimetry As A Test Of The Dark Matter Scattering Model For Flyby Anomalies