You Can Call Me Ray

As we all learned in public school, gamma rays are extremely high frequency photons which often have wavelengths smaller than the width of an atom (there will likely be a quiz following this lesson). Gamma rays are emitted from the nucleus of atoms during radioactive decay, fusion, fission and other processes about which most of us are clueless. Because they have such short wavelengths they are good at penetrating through things like clothes, skin, bone, lead and our atmosphere. Gamma rays are classified as ionizing radiation because their energy is sufficient to ionize the atoms which absorb them. In this process the gamma ray photon is basically swallowed by an electron orbiting an atom that is struck by the gamma ray. The electron then becomes quite energetic, changes its orbit and begins to behave badly, breaking the bonds the atom has formed with other atoms in the molecule it inhabits. This is bad for us because we are comprised of a large number of complex molecules which function poorly when their constituent atoms are randomly separated, resulting in things like radiation sickness, cancer and genetic mutations.

Luckily we are not often subject to large doses of gamma rays, which is why we are able to generally have children with a reliable configuration of arms and legs; an environment high in gamma rays is inevitably not friendly to life as we know it. There is a persistent level of background radiation, including gamma rays, to which we are continually subjected, and this probably contributes to some of the genetic diseases and malfunctions we experience, but the rate of occurrence is at a low enough level not to threaten the continued existence of the species. One might even argue that the random mutations which result from background radiation have made “the glory that is human evolution” possible. Whether this is a net positive I guess depends on where you are in the food chain. There is, however, a true intergalactic gamma ray monster lurking out in the vast expanse of space which could potentially ionize us all into an ionized cloud of ions. It is the mysterious Gamma Ray Burst (GRB), a kick-ass cosmic death ray which would make Dr. Evil squeal with delight.

The Gamma Ray Burst has been on the list of secret, horrible things astrophysicists must worry about since the 1960s. They were discovered by satellites we had launched to detect nuclear detonations on Earth, but the origin of these gamma rays ultimately proved to be billions of light-years from the Soviet Union, so far away, in fact, that our planet had not yet formed when they began their energetic journeys through space. The source of these bursts, which vary from micro-seconds to minutes in duration, is still the subject of some debate, but the general consensus is that they are the result of the collapse of massive stars which have exhausted their fuel and begin to form black holes (some of the shorter bursts may also result from the joining of neutron stars in a binary system). A process known as inverse Compton Scattering may result in the highly efficient conversion of explosive force into gamma rays during this collapse. While Compton Scattering may sound like something that occurs during a South-Central drive-by, it is actually a means by which the frequency of a photon is reduced through interaction with matter. The inverse of the process increases the frequency, and energy, of the photons, even unto the gamma ray range.

So, the collapse of the star releases truly unimaginable explosive force which is then converted (perhaps) by inverse Compton Scattering into a tight gamma ray beam traveling along the axis of the star’s rotation. This beam, screaming through space at the speed of light, obliterates everything in its path for possibly millions of light years until its energy dissipates adequately to allow stuff to just be incinerated. Eventually the beam subsides, leaving an innocuous signature of residual radiation to be detected by sentient beings billions of light years away. Now, this is not such a gruesome horror story, unless you happen to have been a living creature located somewhere along the beam’s vector of travel, in which case you no longer exist. The good news for us is that these Gamma Ray Bursts are apparently relatively rare, especially given the incalculable number of stars in the Universe, and they also appear to mainly originate from very distant, and therefore much younger, galaxies. It is possible that there is something about the evolution of star formation that makes these powerful GBR’s less likely as a galaxy ages. Like many things about our Universe, however, Gamma Ray Bursts are still poorly understood and new data will likely result in new theories.

Suffice it say there is absolutely nothing we can do with current technology to prevent or protect against Gamma Ray Bursts. If they originate from the collapse of a nearby star, it is unlikely that there will ever be any possibility of providential action, so, as with all manifestations of the wrath of God, our best defense is to tell our children that we love them, scratch the spot on the dog’s back that it cannot reach itself, be kind to complete strangers, if only from a safe distance, and to recognize the vanity of arrogance and the emptiness of anger. Because gamma rays travel at the speed of light, there will be no warning and no lucid moment of acceptance, and all that we have thought, dreamed, built or become will be reduced to the primal dust of creation before we notice we’re gone.