Can a photon be emitted with a wavelength > 299,792,458 meters, and would this violate c? Just curious if the possibility exists (not necessarily spontaneously) for a photon with a wavelength greater than the distance component of c to be emitted, and would this inherently violate the scalar c?
 A: See http://en.wikipedia.org/wiki/Ultra_low_frequency
EM frequencies below 1Hz, and therefore with a wavelength longer than c meters can be observed in nature. This does not violate relativity since those waves still propagate with velocity c (in vacuum).
A: $$c=\nu\lambda$$
The waves will still travel at $c$. Changing $\lambda$ changes $\nu$, not $c$.
If, in SI units, $c<\lambda$, then $\nu<1 \text{ Hz}$. These can exist, though we don't come across them often. Ultra-redshifted light coming from sources near a black hole have such frequencies (A source just entering the event horizon gets redshifted all the way to $\nu=0,\lambda=\infty$).
Update: As leftaroundabout pointed out, such low frequency waves are possible when dealing with the transmission of electromagnetic fields. So shaking a charged balloon or any small current can give such photons.
A: It's probably best not to think of wavelength as anything to do with the size of the photon but more as a convenient way to think about frequency.
Imagine a police car with a flashing light going at constant speed. If it's doing 36kph and the light flashes 1/second then the flash will appear every 10m along the road - you could think of this as a 10m wavelength. But really it's just a way of describing the speed and frequency.
