Strongest and Brightest Explosion in the Universe

Imagine you could gather the energy from every star within 100 billion light years, with thousands of galaxies and billions of stars. Imagine you could take this power and use it to fire the biggest super weapon in the universe. The thing is, you don't need to imagine it because these exist and they are called gamma ray bursts. In order to understand gamma ray bursts, we first have to understand gamma rays. Gamma rays are electromagnetic radiation waves that carry energy just like visible light does. Visible light is a tiny part of the radiation spectrum that our eyes can see. Gamma rays are located at the highest energy and frequency part of the spectrum. A single gamma ray photon is more energetic than a million visible light photons combined. Their high energy makes gamma rays a form of ionizing radiation meaning they are energetic enough to break apart atomic bombs. Fortunately, the ozone layer of Earth blocks gamma rays from getting in, since gamma rays are very dangerous. If gamma rays are blocked by the atmosphere, how were gamma rays bursts discovered? During the Cold War, the USA sent up spy satellites which could detect gamma rays from soviet nuclear tests in space. They didn't see any bombs, but they did see faint bursts coming from space lasting only a few seconds. 

The first gamma ray burst was discovered in a galaxy 6 billion light years away. If the satellites were able to see something from so far away, then it must be incredibly energetic and bright. A gamma ray burst, although only lasting a couple seconds, "produce as much energy as the Sun will emit during its entire 10-billion-year existence," (space.com), making gamma ray bursts the brightest events in the universe. 

There are two types of gamma ray bursts: short and long gamma ray bursts and each has their own source. Long gamma ray bursts last about a minute, and some scientists believe they are created by supernova, when the core of a massive star collapses to become a black hole. Short gamma ray bursts last only a couple seconds, and are produced when two neutron stars in a binary, merge. Over the course of millions of years, their orbits decay by emitting gravitational waves. Once the two neutron stars are close enough, they crash into each other causing a black hole. Both supernova and neutron star merges create the same thing, blackholes, surrounded by a magnetized disk of gas, leftover from their parent stars. Within this environment, the rotation that winds up the magnetic field, which funnels hot jets of particles traveling at nearly the speed of light. The gas in these funnels create two tight jets of high energy gamma rays. 

There are still many unknowns about gamma-ray bursts. Recent observations have shown that the photons emitted from gamma-ray bursts all oscillate in the same direction, but for some reason, the direction changes over time. Gamma-ray bursts also seem to focus their energy in a narrow beam, rather than emitting it equally in every direction, meaning that our satellites are missing many of them. Astronomers estimate that, although satellites spot about one gamma-ray burst per day, roughly 500 are occurring within the same time period. So far, gamma-ray bursts have only been detected in distant galaxies. However, it is possible for one to occur in our Milky Way galaxy. If a new gamma-ray burst were to happen near Earth, it would strip our planet's protective ozone layer away and expose all life to deadly ultraviolet radiation. So, although scientists might appreciate the opportunity to witness a gamma-ray burst up close one day, they're also ok with not observing one in our home galaxy.  

Works Cited:

• Mann, Adam. “What Is a Gamma-Ray Burst?” Space.com, Space, 15 Jan. 2020, www.space.com/gamma-ray-burst.html.
• “Gamma-Ray Bursts.” NASA, NASA, 2013, imagine.gsfc.nasa.gov/science/objects/bursts1.html.
• Information@eso.org. “Gamma-Ray Bursts.” ESO, www.eso.org/public/science/grb/.