44-year-old Voyager 2 data sheds light on solar system's magnetic personalities

Researchers, after discovering magnetosheath jets around Jupiter, now believe these phenomena may exist on all solar system planets. A team based in China used data from NASA's Voyager 2 probe – which launched in 1977 and left the heliosphere in 2018 – to show that jets of charged particle plasma can be found in the …

[ldo]

“Shock Wave” Versus “Sound Wave”

As I understand it, a “shock wave” moves faster than the speed of sound in the material. Or rather, it exceeds the normal speed of sound. It does this by pushing the material into a region of nonlinearity: the pressure becomes so high that it temporarily changes to a different phase, with a higher speed of sound. Of course, once the pressure peak passes, the medium reverts to its more usual phase. Or, in other words, a shock wave is a sound wave that creates its own different version of the propagation medium.

So every time you see the word “shock” being used to describe contact between fluids, you can assume that this sort of thing is happening.

[Michael H.F. Wilkinson]

Fascinating stuff!

It goes to show what can be achieved by carefully sifting through existing, shared data, rather than making new observations or building new instruments. The insights gleaned can shape the form of new observations and the design of the inevitable new instruments we need as well. Open, shared data is the best way forward for science.