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Why Gamma Ray Bursts Are the Most Epic of All Apocalyptic Scenarios

Gamma ray bursts: Fine purveyors of existential dread since 1967.
Kurzgesagt (In a Nutshell) takes on GRBs. Video: Kurzgesagt (In a Nutshell)/YouTube

Asteroid impacts. Nuclear war. Unhinged climate change. These are all respectable, solid entries into the great pantheon of doomsday scenarios that could wipe out life on Earth.

But when it comes to sheer destructive flair, gamma ray bursts (GRBs) take the apocalyptic cake. Forged in catastrophic cosmic disruptions like supernovae and neutron star mergers, GRBs are the brightest phenomena in the universe. Capable of releasing more energy in a single second than the Sun will in its entire lifetime of ten billion years, these bursts are essentially the universe's unique riff on projectile barfing.


The mind-boggling force and fascinating observational history of GRBs is explored in this newly released short from Kurzgesagt (In a Nutshell), a channel famed for its lighthearted animated primers on complex topics. The video's narrator does not shy away from the epic, face-melting powers of these events, referring to them alternately as "cosmic snipers," "celestial laser guns," and "the biggest superweapon in the universe."

Kurzgesagt (In a Nutshell) takes on GRBs. Video: Kurzgesagt (In a Nutshell)/YouTube

Interestingly enough, GRBs were first discovered accidentally by an American spy satellite series called Vela, which were launched to monitor Soviet orbital activities during the Space Race. The Vela satellites were built to detect gamma ray radiation from any nuclear detonation tests that the USSR might conduct in space.

Fortunately, the satellites came up blank on space nukes, but in 1967, they picked up the first signatures of a gamma ray burst. Perplexed by its blinding luminosity and prolonged eruption, scientists accelerated observations of GRBs, and found that the universe clearly enjoys shooting them off.

Today, thousands of these bursts have been observed and catalogued in many distant galaxies. To get a sense of just how often these cosmic plasma guns fire, check out this online visual history hosted by UC Berkeley.

It's a bit disconcerting to watch the skies light up with these genuine death rays, each one a merciless destroyer of countless worlds unknown to us. There's some comfort in the fact that GRBs have never been observed within our own Milky Way galaxy, but by no means does that mean that they couldn't rain down on us with all their incinerating power.


"A nearby GRB could be disastrous," the Kurzgesagt narrator points out. "If one goes off within a few light years of us it would totally cook the surface of the Earth, or at least, the half that is facing it. But even a more distant GRB could end life on Earth, and it wouldn't need to score a headshot to kill us."

Concept art of a distant burst known as GRB 090423. Image: ESO/A. Roquette

In fact, a popular theory suggests that Earth may have already been rocked by a gamma ray burst, which sparked the Ordovician mass extinction event 450 million years ago.

GRBs have even been put forward as a solution for the Fermi paradox, which highlights the contradiction between the wealth of life we might expect to find in the wider universe, compared to the eerie silence that actually confronts us.

How many intelligent civilizations might have gone up in gamma ray smoke over the course of billions of years? Could we be the next one up in the cosmic crosshairs?

It's unlikely, but certainly not impossible. And to add a little more nightmare fuel to the general existential dread GRBs evoke, it's worth noting that there is absolutely nothing we can do to stop them.

"Since gamma rays travel at the speed of light, we won't know one is headed our way until it arrives," the Kurzgesagt short concludes. "So there could already be a GRB on its way to kill us all, and we won't know until it hits us, and we're dead."

Sleep tight!