system
Given the following post, respond as if you're commenting on Reddit:
human
How does any photon reach exactly the energy needed to excite a particular atom?

I know that quantum mechanics states  that some things, like bumping an electron to a higher energy level,  requires something like a photon to have juuuuust the right energy for  the electron to 'accept' that photon and then rise to the higher energy  level.

But it is always explained  that it has to be exact. Like, EXACT exact. It must be, let's say,  10,854.7952 electron volts, which corresponds to a frequency of  12.795832 GHz (ignore the actual values, I just pulled some numbers out  of my head). It is always explained that if it were even slightly higher  or lower than that amount of energy, the electron wouldn't be excited  by it.

Well, what are the odds  that a photon with that very very VERY exact energy level would come  passing by in any reasonable amount of time? I know photons are a tiny  amount of energy and there are a huge number of them all the time, but  still, it seems like such a precise requirement would be very  restrictive, and would result in almost no interactions between  particles and the EM force.

It seems like all my assumptions can't be right here. What am I missing?
gpt
There's a relationship between the uncertainty in the energy of an excited state and the lifetime of that state. This creates the "natural linewidth" of a spectral line. The fundamental broadening of a spectroscopic line that cannot be narrowed by any sort of improved spectrometer design because it's just due to the Heisenberg uncertainty principle. 

In essence the shorter the lifetime of a state, the less precise the energy of that state. But no matter what there is always some fundamental breadth to the energy spectrum.