Tag Archives: atomic bomb

Scientists discover new quasicrystal formed by first-ever nuclear explosion at Trinity Site

The red trinitite sample containing the newly discovered quasicrystal. Credit: Luca Bindi and Paul J. Steinhardt.

On July 16, 1945, the United States Army performed the very first atomic bomb detonation at Trinity Site, New Mexico. The traumatic event obliterated the 30-meter-high test tower, as well as all the miles of copper wires that were connected to measuring and recording instruments. Strikingly, this vaporized debris fused with sand to form a new glassy material known as trinitite, which scientists have recently found at the site — a testament to the devastating, matter-altering power of nuclear weapons.

The red trinitite (Si61Cu30Ca7Fe2) has 5-fold rotational symmetry, which is not possible in a natural crystal. For this reason, it is classed as a “quasicrystal”, exotic materials that do not follow the rules of classical crystallization.

Most crystals are composed of a three-dimensional arrangement of atoms that repeat in an orderly pattern. Depending on their chemical composition, they have different symmetries. For example, atoms arranged in repeating cubes have fourfold symmetry. Atoms arranged as equilateral triangles have threefold symmetries.

Quasicrystals have an atomic structure of the constituent elements, but the pattern is not periodic (it never repeats itself).

They’re remarkable for two reasons: firstly, they’re incredibly rare in nature, and secondly, they’re incredibly unlikely. In fact, when the existence of quasicrystals was first predicted, it cost the career of Daniel Shechtman, the Israeli chemist who first discovered them and lost his job because everyone thought he was mad.

“The head of my lab came to me smiling sheepishly, and put a book on my desk and said: ‘Danny, why don’t you read this and see that it is impossible what you are saying,’” Shechtman, now employed at the Technion – Israel Institute of Technology in Haifa, once recounted.

Shechtman was vindicated decades later after he was awarded the 2011 Nobel Prize in Chemistry.

An aerial view of ground zero 28 hours after the Trinity Test on July 16, 1945. Credit: Los Alamos National Laboratory.

Now, physicists at the Los Alamos National Laboratory have published a new study showing how the extreme shock, temperature, and pressure caused by a nuclear blast can birth new quasicrystals. Using scanning electron microscopy and X-ray diffraction, the researchers revealed the atomic structure of the 20-sided quasicrystal and its five-fold rotational symmetry that used to be considered impossible by conventional standards.

Back-scattered scanning electron microscope image of the sample containing the quasicrystal. Credit: Luca Bindi and Paul J. Steinhardt.

The scientists still don’t know exactly how the trinitite formed step by step, but it seems like the thermodynamic shock under which this quasicrystal formed is comparable to the conditions that led to the formation of natural quasicrystals found in the Khatyrka meteorite, dating back hundreds of millions of year ago.

“This quasicrystal is magnificent in its complexity—but nobody can yet tell us why it was formed in this way. But someday, a scientist or engineer is going to figure that out and the scales will be lifted from our eyes and we will have a thermodynamic explanation for its creation. Then, I hope, we can use that knowledge to better understand nuclear explosions and ultimately lead to a more complete picture of what a nuclear test represents,” said Terry C. Wallace, director emeritus of Los Alamos National Laboratory and co-author of the paper.

This trinitite is effectively the oldest artificial quasicrystal and could someday help scientists better understand illicit nuclear blasts and curb nuclear proliferation.

A mushroom cloud billows into the sky about an hour after an atomic bomb was dropped on Hiroshima, Japan. US Army via Hiroshima Peace Memorial Museum.

Victim’s jawbone shows shocking intensity of Hiroshima nuclear attack

During the final stage of World War II, the United States detonated two nuclear weapons over the Japanese cities of Hiroshima and Nagasaki on August 6 and 9, 1945, respectively. The A-bomb nicknamed “Little Boy” that blew over Hiroshima instantly killed 45,000 people and would go on to claim the lives of thousands more as a result of nuclear fallout. In a novel research, scientists have now used measured how much radiation was absorbed by the bones of one of the casualties, who was less than a mile away from where the bomb was set off.

A mushroom cloud billows into the sky about an hour after an atomic bomb was dropped on Hiroshima, Japan. US Army via Hiroshima Peace Memorial Museum.

A mushroom cloud billows into the sky about an hour after an atomic bomb was dropped on Hiroshima, Japan. US Army via Hiroshima Peace Memorial Museum.

Most of the research that studied the effects of A-bomb radiation on the human body focused on how nuclear fallout exposure affects the health of victims. We know, for instance, that approximately 1,900 people, or about 0.5% of the post-bombing population, are believed to have died from cancers attributable to Little Boy’s radiation release. The new study performed by Brazilian researchers at the University of São Paulo is different: it’s the first to measure direct blast radiation exposure, effectively using a victim’s jawbone as a dosimeter — a device used to measure an absorbed dose of ionizing radiation.

Little Boy held about 140 pounds of uranium, which underwent nuclear fission when it exploded as planned nearly 2,000 feet above the Japanese city. The blast released 16 kilotons of explosive force, causing unspeakable damage in the area. According to one estimate, at least 50,000 people were killed and an equal number were injured that day. Nearly 70% of the city’s buildings were destroyed, leaving many homeless.

One of the unfortunate victims was less than a mile away from the bomb’s hypocenter. Using a technique called electron spin resonance (ESR), the researchers estimate that the jawbone’s radiation dose was about 9.46 grays (Gy) — the measurement unit of absorbed radiation dose of ionizing radiation, e.g. X-rays. The gray is defined as the absorption of one joule of ionizing radiation by one kilogram (1 J/kg) of matter, e.g. human tissue.

For cancer patients, doctors often target tumors with a collimated beam, a radiotherapy which can involve up to 70 Gy’s in some cases. However, a person whose whole body is exposed to 3-5 Gy’s can expect to die within a couple weeks. The jawbone’s radiation dose measured a staggering 9.46 grays (Gy).

The innovative method used by the Brazilian researchers was first demonstrated in the 1970s by Sérgio Mascarenhas, who was at the time teaching at the University of São Paulo’s São Carlos Physics Institute (IFSC-USP). The physicist wrote a widely-acclaimed paper that concluded that X-ray and gamma-ray irradiation makes human bones slightly magnetic, a phenomenon called paramagnetism. Bones contain a mineral called hydroxyapatite which, when irradiated, produces CO2 whose levels can be traced inside the mineral. The resulting free radicals can then be used to gauge the radiation dose in bone.

The mandible studied by the researchers. Credit: Credit: Sergio Mascarenhas (IFSC-USP).

The mandible studied by the researchers. Credit: Credit: Sergio Mascarenhas (IFSC-USP).

Initially, Mascarenhas’ technique was intended to be a new tool for dating bones from archeological sites in his country based on how much radiation they’d received from elements like thorium that occur naturally in the sand. One day, however, he was invited to test his technique on the remains of people from the Hiroshima blast. Unfortunately, his analysis was far too rudimentary at the time — due to the lack of advanced computers, the physicist was unable to separate the A-bomb signal from the background signal. He did get to keep the jawbone though.

Decades later, Angela Kinoshita of Universidade do Sagrado Coração in São Paulo State, along with colleagues, used modern equipment to finally make the method work. The dose distribution matched that found in different materials around Hiroshima, including wall bricks and roof tiles, suggesting that the method is accurate, although more experiments are still required.

“There were serious doubts about the feasibility of using this methodology to determine the radiation dose deposited in these samples,” Kinoshita said in a press release.

“The results confirm its feasibility and open up various possibilities for future research that may clarify details of the nuclear attack.”

There is a lot of interest in this methodology due to the risk of terrorist attacks in countries like the United States.

“Imagine someone in New York planting an ordinary bomb with a small amount of radioactive material stuck to the explosive,” said study co-author Oswaldo Baffa of the University of São Paulo’s Ribeirão Preto School of Philosophy, Science & Letters.

“Techniques like this can help identify who has been exposed to radioactive fallout and needs treatment.”

The findings appeared in the journal PLOS ONE. 

How science knows when nations are testing nuclear bombs — even when they are lying

The entire world is abuzz with news that North Korea is testing nuclear weapons. But how can we be sure what’s going on? Well, science has an elegant solution to that problem — and it has a lot to do with earthquakes.

The seismological observatory NORSAR at Kjeller, Norway, is one of the instruments which detected the latest underground nuclear test by North Korea.

Earthquakes vs bombs

Every time an earthquake happens, thousands of devices all around the world record it. These are the seismographs, and they measure movements associated with earthquakes. This global network has proven instrumental for a number of reasons.

For starters, we can know the location of all earthquakes (to some degree of certainty). We’ve long deduced the speed of seismic waves, and by calculating the arrival time of these waves at different places across the Earth’s surface, we can know where an earthquake happened and triangulate the epicenter. This also helped us greatly expand our understanding of the planet’s subsurface, and earthquakes allow us to “see” way deeper than we could ever hope otherwise.

We can also tell a lot about the earthquake intensity — its energy. The Richter magnitude (the most commonly used scale) is basically determined from the logarithm of the amplitude of waves recorded by seismographs. So an earthquake with a magnitude of 7 is ten times stronger than that with a magnitude of 6. But we can go even deeper into the mechanism of the earthquake: we can study its source, through the waves we see.

All earthquakes have three types of waves: P waves (primary), S waves (secondary), and surface wave (Love and Rayleigh waves). This is where it really gets interesting.

The different types of seismic waves.

Although surface waves are typically the most destructive, P waves are the fastest. These P waves are essentially alternative extensions and compressions of matter along a trajectory — think of someone playing the accordion. Now, imagine an earthquake happening. Some part of the ground snaps. When it triggers, it produces these waves, and if you plot P waves over a stereographic projection, you end up with a so-called beachball diagram. These diagrams show that for the first movement, some directions are extensions, while the perpendicular directions are contractions. It’s not the easiest thing to wrap your head around, but let’s just say that for every earthquake, P waves start as extensions over half of all possible directions, and contractions in the other half.

Types of ‘beachball’ plots associated with fault end-members. A diagram for an explosion would be all black. Image via Wikipedia.

Whenever an underground explosion happens, it only produces contractions. So for an underground explosion, you wouldn’t end up with a beachball diagram that’s half white and half black — you’d end up with one that’s all black. In other words, the pattern of energy in a bomb-related earthquake is completely different than that of a natural earthquake.

“As the bomb is detonating, it’s compressing the rock immediately adjacent to it, and that propagates out to the recording stations” as waves, said Douglas Dreger, a seismologist at the University of California, Berkeley.

The relative amplitude of waves can also be an indicator of an explosion and not a natural earthquake. The bottom line is, you can’t really fake the seismic signature of an underground explosion — people will be able to tell whether or not you tested a bomb, and approximately how strong it is.

[Also read our previous article on this topic: Did North Korea actually test a bomb? Science has the answer]

Why underground?

While we’re discussing detecting underground explosions, it makes sense to ask the question — why underground? Why not just test it in the air, or underwater? Well, if you want to hide something, underground is just your best bet. People will still know you did something, but you have a decent chance to at least hide some information.

Air does very little to muffle the sound of an explosion. Furthermore, explosions also generate infrasonic (long wavelength, low frequency) waves that are very easy to pick up on detectors all around the world. Radiation might also be detected. So if you want to carry an experiment, air does basically nothing to hide it.

Water is a bit better. The energy of the waves dissipates more than in air, but since there are no natural sources that can produce such earthquakes underwater, you’d again be creating an easily detectable smoking gun.

By going underground, you’re at least putting a mask on your smoking gun. Vigilant observers will still be able to see what you’re doing, but at least you’ll be making it hard for them, and if you’re lucky, you might create some uncertainty around the energy of the bomb.

Routine measurements

Basically, only North Korea is testing nuclear weapons at this point. Image via Wikipedia.

This is not really groundbreaking science — it’s been known for decades. It’s this technology that allowed the implementation of the Treaty on the Non-Proliferation of Nuclear Weapons, commonly known as the Non-Proliferation Treaty. According to the treaty, no nation is allowed to conduct nuclear tests, but there’s not much point in having such a deal if you can’t verify it, is there?

So most nations on Earth have at least some form of seismological monitoring which not only studies earthquakes but also detects such explosions. We can’t really know what kind of a bomb it is (was it really an H bomb?), but we can infer several things about it, with decent certainty.

The biggest question is, was it fusion or fission? Both bomb types release large quantities of energy from relatively small amounts of matter. However, the fundamental principle is different. Fission bombs use heavy elements such as uranium and plutonium and break them down into unstable isotopes when bombarded with neutrons. Meanwhile, fusion bombs take the opposite approach: they use light elements such as hydrogen and combine them into heavier elements such as helium, releasing even more energy in the process. The required energy is so great, that the only way we’ve figured out to make such a bomb is by surrounding it with a fission bomb to power it up.

A-bomb vs H-bomb comparison. Image via Wikipedia.

So you can get an idea about the scale we’re talking, the first test of a fission (“atomic”) bomb released an amount of energy approximately equal to 20,000 tons of TN. The first thermonuclear (“hydrogen”) bomb test released energy approximately equal to 10 million tons of TNT.

North Korea’s tests

The figure below shows the estimated locations within the Pungggye-ri test site of the five previous tests (red dots). The tests are conducted in the tunnel system inside the mountain. The area of the likely location of the most recent test is indicated in the figure. Some additional work is required in order to estimate a precise location. Image credits: Norsar seismic array.

This leads us to North Korea’s tests. They claim to have tested a hydrogen bomb, but judging by the energy observed in the North Korean tests, there’s almost no way that’s true. If it were indeed an H bomb, it would be the most efficient fussion we’ve ever seen, something many researchers don’t even believe is possible. So right now, all the evidence is pointing towards a fission bomb, what’s often called an atomic bomb. It’s possible that they did assemble an H bomb, but for some reason, it failed, or that they’re just bluffing. Even an atomic bomb would likely be enough to completely wipe an average city, so this shouldn’t be treated lightly. In fact, few things are as frightening as a nuclear war.

So here’s what we know so far:

  • North Korea is conducting underground tests of bombs. We know this through a study of seismic waves.
  • They say that future tests will include an open air test.
  • They say they have an H bomb, but evidence indicates that they’ve “only” exploded an atomic bomb.
  • Even such an atomic could lead to gargantuan explosions and cause unprecedented damage.

South Korea claims North Korea is preparing for another nuclear test

The atmosphere is getting more and more packed with tension between the two Koreas, as satellite images revealed North Korea is digging a huge underground tunnel, in what appears to be preparation for a new nuclear test.

Nuclear tests raise global concern

North Korea performed two previous tests, both of which were significantly smaller than the Hiroshima and Nagasaki bombs, but they frightened people throughout the entire world – and world leaders as well, who claim that North Korea is too much of a loose cannon to be trusted with nuclear weapons, especially given their recent conflicts with South Korea.

The excavation at North Korea’s northeast Punggye-ri site, where nuclear tests were conducted in 2006 and 2009, is in its final stages, according to a report released by South Korean intelligence, shared with the Associated Press.

Observers fear a repeat of 2009, when massive international criticism was aimed at North Korea for a long-range rocket launch, forcing Pyongyang to walk away from nuclear disarmament negotiations, and just a few weeks later, to perform their second nuclear test, which was much more powerful than the first one.

“North Korea is covertly preparing for a third nuclear test, which would be another grave provocation,” said the report, which cited U.S. commercial satellite photos taken April 1. “North Korea is digging up a new underground tunnel at the Punggye-ri nuclear test site, in addition to its existing two underground tunnels, and it has been confirmed that the excavation works are in the final stages.”

Monitoring nuclear tests

You can’t really conduct a nuclear test and get away with it unnoticed; whenever such a test is performed, be it on the ground, underground or underwater, it creates a small earthquake which is recorded at seismic stations all over the world. There, seismologists can differentiate it from a regular earthquake, and furthermore, by comparison, they can estimate the size of the bomb which was launched. If such an event is detected, radiation monitors immediately step in and confirm this.

Now, North Korea is perhaps the most volatile country in the world, especially after the death of Kim Jong Il, and after the U.S., Japan, Britain and many more other countries urged them to stop the nuclear tests, which are in a direct violation of the U.N. resolutions, and North Korea’s promise to refrain from doing so, things can only get worse; one can only hope reason and peace will prevail, despite the odds, and people will understand that a nuclear war is the absolute last thing the world needs right now – ever.

Via AP

Five minutes to midnight: doomsday clock moves one minute closer to Armageddon

The Bulletin of the Atomic Scientists agreed that the world is less safe than it was two years ago – just 5 minutes to midnight.

Let me tell you what this is about. When the atomic bomb was created, by people in all levels of academia and research, people were stunned by the amount of damage it did, so as a response, a group of atomic scientists created the ‘Doomsday Clock‘. The clock is basically a simple countdown image which represents the danger the human race faces on this planet, be it nuclear, environmental, or of other nature.

Since it was created in 1947, the clock has been moved 20 times (forward and backward), the last time in 2010 when Barack Obama was elected president and the entire world was filled with hope of peace. However, now, as the lack of action has become obvious and mankind still continues to ignore the huge amount of environmental damage it does, the clock has moved one minute closer to ‘midnight’ – quite the metaphor if you ask me.

“It is five minutes to midnight,” the official statement from the Bulletin of Atomic Scientists (BAS) read. “Two years ago, it appeared that world leaders might address the truly global threats that we face. In many cases, that trend has not continued or been reversed. Faced with clear and present dangers of nuclear proliferation and climate change, and the need to find sustainable and safe sources of energy, world leaders are failing to change business as usual,” said Lawrence Krauss, a board member of the BAS.

What is perhaps most dangerous is the fact that we are approaching the point of no return – the point where it will be practically impossible to reverse the damage we have done on the planet, and on to ourselves.

When the clock was created, it was set at 7 minutes to midnight, but after only two years it went forward five minutes – it was the highlight of the Cold War, when both the US and the USSR were testing nuclear weapons. The fall of the Berlin Wall and the dissolution of the USSR set it farthest, at 17 minutes in 1991. However, the peaceful feeling slowly faded away until today.

Now, it’s hard to say if this is a good indication, and if the human race is closer to a tragic event than it was 24 months ago, but one could argue that growing interest in nuclear power from countries such as Turkey, Indonesia and the United Arab Emirates is a dangerous thing, and that Canada backing up from the Kyoto Pact and increasing emissions is dangerous, but it’s really hard to quantify just how dangerous. If you ask me, we should take this as a wake up call, and not the usual Maya 2012 idiotic juvenile approach. It’s in our hands.