Spinning pulsars. Degenerate matter. Ghost particles. Oh, my.
In today's remarkably trippy DNews report, Trace Dominguez considers the seemingly simple matter of friction in space -- and finds out there's nothing simple about it at all.
First, the news: Recent astronomical observations published in Astrophysical Journal suggests that some kind of mysterious friction effect is slowing down the rotation of pulsars in space. This struck physicists as odd, since space is a vacuum and by definition entirely void of matter. What could the pulsars be rubbing against to slow down their spinning?
Welcome to the weird world of friction in space. Friction, as you know, refers to the resistance that one surface or object encounters when moving over another. But that's down here on Earth. Up in space, friction as we know doesn't really exist, but a different kind of friction apparently does.
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That's because, according to quantum physics, any given cube of cosmic space-time is actually buzzing with ghost particles -- extremely tiny bits of virtual matter that pop into existence then immediately disappear from our universe. Traditional physics typically doesn't truck with this kind of nonsense -- disappearing matter -- but these ghost particles flash and fade so quickly that they do nothing wrong in the eyes of the law (of physics).
While these particles are referred to as ghosts, they have a very real impact on space-time and the objects in it. A good example is Hawking radiation, a phenomenon which causes black holes to evaporate as ghost particles pull away mass from their center.
Physicists suspect that a similar process is happening with those spinning pulsars, which are a variety of neutron star made from degenerate matter -- an oddly disparaging term for the densest substance in the cosmos. (As we say, it gets trippy: One shot glass full of degenerate matter would weigh as much as Mount Everest.)
Anyway, the theory is that ghost particles create a kind of pervasive quantum friction throughout the universe. Those pulsars are slowing down because those ghost particles have their own tiny magnetic fields, which interfere with the pulsar's magnetic field. It gets a lot more complicated -- check out Trace's video for a deeper dive into the topic.
-- Glenn McDonald
Physics World: Pulsar Timekeepers Measure Up To Atomic Clocks
PNAS: Journal Club: Friction Of The Vacuum Could Slow The Rotation Of Pulsars
Universe Today: Hawking Radiation