https://en.wikipedia.org/wiki/Very-high-energy_gamma_ray Wikipedia says this about Very-High-Energy Gamma Rays: This is approximately equal to wavelengths between 1.24 × 10−17 and 1.24 × 10−20 meters, or frequencies of 2.42 × 1025 to 2.42 × 1028 Hz. Such energy levels have been detected from emissions from astronomical sources such as some binary star systems containing a compact object. Wikipedia also says a helium atom is 62 picometers across essentially. 1st question: Of the photons detected, how small in picometers is the shortest wavelength photon? I need to know how many "fit" within an atom. These photons have gotta be at least as small as quarks. 2nd question: I don't understand why "1.24" is in front of "× 10−20 meters". Do they mean a 0.2 with 20 0s after it? Times 1.24? 3rd question: And lastly the frequency, "2.42 × 1028 Hz", shouldn't this number be double the wavelength? And how do they know its frequency - do they register each "hit" within 1 second?