With every development in technology and every increase in the sensitivity of detection instruments, it seems the universe only ever gets larger and more complicated. With the advent of the microscope came the discovery of worlds within worlds, bacteria and microbes living their lives parallel to our own. With computers and advanced digital modeling came the understanding of the workings of DNA and genomes — only to leave us wanting ever more as we found these structures to be more elegant and complex than we could have imagined.
Now NASA has shed new light on a phenomenon that has been with us since the dawn of time. Using the Fermi Gamma-Ray space telescope, researchers have discovered that our very own planet generates and launches beams of antimatter into space.
There have been longstanding hypotheses that postulated the creation of antimatter within thunderstorms as a result of the enormous voltages created by lightning. It was only recently, though, that scientists have discovered this to be true.
The Fermi Gamma-Ray telescope was designed to further our understanding of the universe by providing us with a way to observe high-energy gamma radiation. Allowing us to detect this spectrum gives us access to the workings of dark matter, the mysterious substance composing most of the galaxy.
First discovered in the 1930s by Fritz Zwicky, dark matter explains the reason galaxies contain five times more material than we would expect them to have. Normally, we detect cosmic bodies through the radiation they emit — be it visible light, radio waves or other forms of radiation. However, early on, astronomers noticed there was an amount of “missing mass” in the galaxy. The missing mass is currently attributed to this dark matter.
Dark matter does not give off radiation and is thereby invisible to instruments and the human eye. We can still measure dark matter, however. NASA explains the process: “The most common method involves the fact that dark matter has a gravitational pull on both the light and the sources of light that we can see. From the effects of ‘extra’ gravity that we detect, we infer how much mass must be present.”
The Fermi Gamma-Ray space telescope can also detect elusive particles called “antimatter,” which is how the thunderstorm phenomenon was detected.
A particle of antimatter (also called a positron) is the “anti-particle” to an electron, possessing the same mass but opposite charge and magnetic moment. When a particle of matter and antimatter collide, the particles are annihilated and gamma radiation is given off.
The telescope detected antimatter particles through the telltale creation of a 511,000 volt charge, indicating that an electron had collided with a positron. Not surprising in and of itself, it was the terrestrial source of the antimatter that shocked scientists.
It is theorized that antimatter is created in terrestrial gamma ray flashes (TGFs), caused by the immense amounts of energy accumulated during lighting storms. During a thunderstorm, a magnetic field is created as a result of the immense amounts of energy. According to NASA.gov:
“Under the right conditions [. . . ], the field becomes strong enough that it drives an upward avalanche of electrons. Reaching speeds nearly as fast as light, the high-energy electrons give off gamma rays when they’re deflected by air molecules. Normally, these gamma rays are detected as a TGF. But the cascading electrons produce so many gamma rays that they blast electrons and positrons clear out of the atmosphere. This happens when the gamma-ray energy transforms into a pair of particles: an electron and a positron. It’s these particles that reach Fermi’s orbit.”
The Fermi telescope then detects these particles through the previously noted creation of a high-voltage charge. The spacecraft does not necessarily have to be above the storm in question, as there have been some cases where the spacecraft has been a few thousand miles from the source of the TGF. In one case, “Fermi was located over Egypt, but the active storm was in Zambia, some 2,800 miles [4,500 kilometres] to the south. The distant storm was below Fermi’s horizon, so any gamma rays it produced could not have been detected, [ . . . ] [but] the TGF produced high-speed electrons and positrons, which then rode up Earth’s magnetic field to strike the spacecraft.” So far, 130 instances of this phenomenon have been documented
The discovery creates more questions than it answers, but it gives us valuable insights into seemingly growing intricacy of our natural environment. Antimatter is no longer confined to the empty reaches of little understood space or the workings of distant stars. It is being created on our doorstep and without the need for complicated machinery to replicate the phenomenon. The rabbit hole just keeps getting deeper.