Gamma Ray Bursts: The Universe’s Cosmic Death Lasers
Imagine, the energy of 100-million blazing stars being blasted off, like a gigantic cosmic death laser. Surprisingly, these cosmic death weapons are reality. Gamma ray bursts (GRBs) are the universe’s most lethal weapon, and biggest mysteries.
Simply put, gamma ray bursts are extremely powerful explosions observed from distant regions of space. These massive bursts last from only milliseconds, to several minutes. How powerful? Actually, gamma ray bursts emit more energy in a single second than our Sun will in its entire, 10 billion-year life.
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Light: a quick recap
We know that light is measured by a scale called the electromagnetic spectrum. Plus, we know that light travels in packets of energy, called photons. Now, the more energy a photon has, the shorter its wavelength. So, (like the diagram below) microwaves have the longest wavelengths, or least amount of energy. Whereas, gamma rays have the highest energy, and the shortest wavelengths. In fact, a single gamma ray photon has the power of millions of visible light photons.
Discovery of gamma ray bursts: an accident
During the 1960s, the United States launched its Vela satellites to detect gamma rays. However, these satellites aimed to detect rays from Russian nuclear weapons being tested in space. Gradually, the satellites began picking up large gamma ray readings, unlike any known nuclear weapon signature.
Now, detecting bursts on a regular basis, these mysterious gamma ray bursts had scientists baffled. Only lasting for fractions of seconds, astronomers were unable to trace the ray’s origins. Even when they traced bursts to specific regions of space, no nearby objects fit the role of a suspect.
Only recently have astronomers carefully traced GRBs and deduced their potential causes. And, while NASA has teams and technologies dedicated exclusively to GRBs, their causes remain theoretical.
Two types of gamma ray bursts
Now, detecting around one per day, gamma ray bursts are broken into two classes, based on their time length. And, both classes are the result of the same thing, black holes. When a black hole forms, magnetic discs of gas swirl around them. Now, the disc’s magnetic field funnels the energetic gas, shooting massive jets of gamma ray particles. Astronimate explains how black holes form in this article.
Short gamma ray bursts
Accounting for 30% of the detected GRBs, short gamma ray bursts last for less than two seconds. These brief bursts are believed to be caused by two neutron stars colliding. As the two dense stars interact, their immense masses collapse, forming a black hole. To learn more about neutron stars, check out our video:
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Long gamma ray bursts
Nearly 70% of the detected GRBs are long gamma ray bursts, lasting for more than two seconds. Long GRBs occur when a massive star’s core collapses in a supernova. And, the star’s extreme mass collapses, forming a black hole, also releasing the fantastic burst of gamma rays.
Will gamma ray bursts destroy Earth?
Indeed, gamma ray bursts are lethal. In fact, if one struck directly, the Earth’s surface would be completely incinerated. All life would be obliterated.
Fortunately, all GRBs detected have occurred in distant galaxies, far beyond our Milky Way. And, at these distances, Earth remains unharmed. Not to mention, Earth’s atmosphere prevents gamma rays from entering.
However, if a gamma ray burst did occur nearby in our galaxy, the results would be catastrophic. As the bursts travel, they grow increasingly wider. Therefore, a nearby burst would likely grow wide enough to wash over the solar system, eliminating everything in its path.
Besides, at such close distances, a GRB would devour our atmosphere, leaving Earth exposed. And, even if the gamma rays did not destroy Earth, solar radiation would. It takes our ozone layer several years to replenish itself. And, the time it takes to replenish would be ample time for the Sun’s ultraviolet light to incinerate the Earth’s surface!
So, the short answer: no, GRBs will not destroy Earth. They would need to be close by, and directed precisely at Earth, which is highly unlikely. However, gamma rays travel at the speed of light. So, if one did fire at Earth, we would not know that it was coming until it had already arrived. Too late!
Gamma ray bursts and the rest of the universe
Given their deadly potential, GRBs are thought to greatly impact the rest of the universe. In fact, some theories believe GRBs are why there is no life beyond our solar system. Hostile environments tell us that only around 10% of galaxies would be even remotely hospitable.
Actually, some scientists believe GRBs may have been he cause of the mass extinction on Earth, nearly 450-million-years ago.