Tag: nuclear

Posted in Philosophy

Anthroponuclear Multiple Worlds Theory

Posted on by Jinavie

A famous theory in philosophy is the anthropic principle, which argues that the reason the various physical constants and laws of nature are consistent with an environment that can support life is because if life were impossible, no life would be able to observe the universe. Simply put, it argues that the reason the universe seems so improbably perfectly tuned for us to exist in it, is that we exist to observe it.

What if we applied a similar theory to modern world history? Since the advent of nuclear weapons, we now have the capability of destroying human civilisation with the push of a button. There have been so many incidents in the past century where international tensions and mistakes have nearly resulted in thermonuclear war, such as during the Cuban Missile Crisis. However, through improbable coincidences (and the moral fibre of certain heroes), we continue to live on as a species.

But perhaps history only seems so full of coincidences because we are still alive to study it. For our reality to exist, human beings have had to resist the urge to annihilate themselves. Ergo, the longer we live through the Atomic Age, the stranger our reality becomes, as otherwise we would have been wiped out. Zach Weinersmith calls this the anthroponuclear multiple worlds theory.

So perhaps this explains why we are seeing crazier and crazier stories on the news as of late. As in any other sensible timeline, we would all be dead.

(Source: http://smbc-comics.com/index.php?id=3994)

Posted in Science & Nature

Fusion

Posted on by Jinavie

One of the greatest challenges for modern science is unlocking the secret of nuclear fusion. Nuclear fusion presents the opportunity for humanity to obtain an extremely efficient yet surprisingly clean source of energy. Einstein’s famous equation – E=mc² – shows the relationship between energy and mass. It turns out that all matter is essentially energy, meaning that by breaking apart the matter to its basic constituents, you can unleash energy.

When two hydrogen atoms are collided together at extremely high speeds, the two protons join with enough energy to form deuterium, while releasing energy. As more hydrogens are collided, helium is formed while releasing more energy and also hydrogen, which can fuse with other hydrogen to start more reactions. This is a chain reaction. Once the chain reaction is established, the fusion reaction will keep producing immense amounts of energy until it uses up all the hydrogen available.

However, there are two main problems we are still trying to solve when it comes to unlocking fusion. The first is generating enough energy to kickstart the chain reaction in the first place, which is called ignition. The second is containing this immense energy, as the intense heat produced would melt any material we can produce to contain it.

This brief overview of nuclear fusion also offers a lesson in life. Most of the good things in life are not single events, but self-sustaining processes. Things like good habits, happiness and human relationships. To form a good habit, you must invest incredible amounts of time, resources and willpower. To start a relationship, you need to make an effort to show the other person how much they mean to you. To be happy, you need to completely change the way you perceive the world.

The best things in life do not happen by accident, but because you made an effort to ignite the chain reactions. Of course, you will constantly need to maintain those reactions so they don’t explode on you, but at the end of the day, starting is really half the battle.

(Couldn’t come up with an appropriate picture for this article……..so here’s a gif of Groot dancing)

Posted in Science & Nature

Banana Equivalent Dose

Posted on by Jinavie

No form of energy has been more feared or creatively explored in science fiction (e.g. Godzilla) as radiation, yet the layman tends to know little about the actual properties and effects of radiation. The word “radiation” is commonly associated with things like Chernobyl, mutation and cancer. However, most people only know that radiation is “bad” while not knowing exactly how and why it is dangerous. Radiation is essentially high-frequency light which can deliver a large dose of energy (just like how microwaves cook food and sunlight can burn paper when focussed through a magnifying glass). When this high-dose of energy passes through living organisms, it damages the DNA in cells, potentially causing irreparable damage. This can lead to mutation and disruption of cell division (which can lead to cancer) or cell death (which is why radiation is ironically used to kill cancer cells).

The more technical question is “how much” radiation is harmful. For example, how much more dangerous was the Chernobyl incident compared to an x-ray? Like many other things in science, radiation is measured using an internationally universal unit called the Sievert (Sv). The radiation received from standing next to the Chernobyl reactor core after meltdown was 50Sv, while a chest x-ray is 20μSv (1000μSv = 1mSv, 1000mSv = 1Sv). Therefore, the Chernobyl incident could be considered to be as strong as 2.5 million chest x-rays. Although there is great variation, it is considered that a dose of 400mSv can cause symptoms of radiation poisoning, while 4~8Sv of radiation will lead to certain death.

Fascinatingly, radiation is not an uncommon thing. Radiation is all around us, with an average person receiving about 10μSv of background radiation per day just by living on Earth. Ergo, two days of walking around gives you the same amount of radiation as a single chest x-ray. A CT scan gives out a significantly greater dose of radiation at about 7mSv (approximately 350 x-rays or a year’s worth of background radiation).

However, the Sievert is a unit that is difficult to understand. Thus, some scientists devised a clever, humorous equivalent unit called the banana equivalent dose (BED). Bananas contain a certain amount of radioactive isotopes (radioactive potassium), making them technically radioactive. A banana contains 0.1μSv of radiation. Ergo, a chest x-ray is the equivalent to eating 200 bananas, a CT scan is 70000 bananas, while the Chernobyl incident gave people nearby a dose of roughly 500 million bananas.

The banana equivalent dose is a rather useful (and hilarious) way of comparing the danger of radiation from different sources. The next time you go to hospital for an x-ray, just picture 200 bananas being shot through your chest.

Posted in Science & Nature

Nuclear Explosion

Posted on by Jinavie

Nuclear weapons are quite possibly the most dangerous weapons mankind has ever developed. Through the use of nuclear fission, atoms are split to release the massive amounts of energy contained within, causing a gargantuan explosion. When a typical nuclear bomb detonates, energy is released in various forms: blast energy (40~50%), heat (30~50%), radiation (5%) and fallout (5~10%). The distribution of the energy varies according to the type of bomb (e.g. neutron bombs produce significantly more radiation than heat and blast energy).

The initial damage that follows a nuclear explosion is from the blast energy, much like a conventional weapon. The sheer amount of kinetic energy creates a shockwave that pulverises everything in its path, travelling at speeds over 1000km/h. In addition, the heat from the explosion, over ten million degrees celsius at one point, causes vaporisation of all matter within a certain radius, causing a massive release of gases, fuelling the shockwave from the expansion. In the case of the bomb that destroyed Hiroshima, all structures within 1.6km were vaporised and those within a 3.2km radius suffered moderate to severe damage. A modern nuclear weapon is at least tens of times more destructive and will affect a significantly larger area.

At the same time, thermal radiation spreads out in all directions much like sunlight. Thermal radiation travels far further than shockwaves and can cause severe burns and eye injuries (flash blindness) to people in the vicinity (if they are close enough, they will spontaneously combust or melt). Near ground zero (point of explosion), a firestorm may erupt from the sheer amount of heat energy, as observed as a fireball. 

Next comes the indirect effects.
Ionising radiation is produced when atoms are split and these have detrimental effects on living organisms. Not only are they responsible for mutations in the genome, leading to deformed offspring, sterility and cancer, but if there is sufficient radiation, a person will immediately die from acute radiation poisoning.
The same radiation, especially gamma rays, creates what is called an electromagnetic pulse (EMP). EMP is caught by metal objects and induces a high voltage surge, destroying unshielded electronic devices. Sometimes, nuclear bombs are detonated at very high altitudes so that only the EMP affects the ground, damaging enemy communications and destroying entire power grids.
Lastly, radioactive material rains from the sky for long periods of time, also known as fallout. Fallout causes continuous radiation damage in affected areas.

A nuclear bomb is truly a weapon of mass destruction as it utilises various forms of destruction to devastate all life forms within an area spanning several kilometres, even killing over the course of time in the form of radiation.