w/e i plug my laptop cooler in to my laptops usb port and put my headphones on i get this weird static noise like a mosquito is buzzing around near my ear (its pretty loud but not loud enough to notice when im playing a game). If i turn the laptop cooler off the noise is gone. Whats causing this?
You've got coils that energize and pull a chunk of something (very technical term!) towards them. Before the center of that coil's magnetic field is reached, that coil needs to turn off, and the next one in line turn on.
http://www.allaboutcircuits.com/vol_2/chpt_13/6.html
A DC brushless motor works just like an AC one, just that with AC, the power line's voltage changes are used for powering them up or down, while a DC motor has them switched on or off based on rotor position.
The same mechanism that pulls to make the rotor spin, by having applied voltage to a set of coils, can also induce current in coils turned off (spin an unpowered motor, and you'll be generating electricity). That could cause noise. Also, the abrupt turning on or off of the coils, without sufficient damping (usually just by a capacitor or two), might cause audible noise. There could be other causes too, or that could make it worse, like PWM speed control (turning the fans on an off hundreds or thousands of times a second).
It's also possible, instead, that the noise you hear is directly from the magnetic fields inducing current in your headphone wiring, or the internal analog audio wiring (same causes as above, but not actually due to messing with the ground rail(s)). In that case, all you can do is use some other audio port, or a different cooler
[, and get laptop that can cool itself without external aid, next time].
P.S. The magnetic field hypothesis can be tested, by moving the laptop towards and away from the cooler, while listening.