Tag: encyclopaedia

Posted in Science & Nature

Zero Gravity

Posted on by Jinavie

With the development of technology, we are now at a point in history where there is an abundance of video footages taken in space. Thanks to this, the general population can visualise the strange phenomenon that is the lack of gravity in space. We are able to see videos of objects and astronauts gently floating and even strange phenomena such as tears simply pooling around a person’s eyes rather than streaming down the face. Most of these scenes are from places such as the International Space Station which is in orbit around the Earth, as there has been no expeditions leaving Earth’s orbit since the last moon landing in 1972.

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However, the common misconception is that objects in space stations are in zero gravity conditions. Objects in orbit are still under the influence of Earth’s gravity, which is why they do not fling out into the depths of space. So why do astronauts in space stations look like they are not under the influence of gravity? The reason is that an object in orbit is travelling incredibly fast.

The International Space Station is about 420km above the surface of the Earth. Here, it experiences about 90% of Earth’s surface gravity, meaning that theoretically, it should fall straight back. However, the ISS is travelling at 8km/s (27600km/h) sideways at the same time – the orbital speed. Because of this, the ISS is falling back to Earth at the same rate as it is travelling tangentially away from Earth. This makes it travel at a blistering speed in a circle around the Earth.

Not only is the ISS free-falling around the Earth, but so is its contents. Therefore, the astronauts inside look like they are in zero gravity, but are in fact simply in free-fall, much like a skydiver. In this state, they experience no “weight” as the g-force becomes zero and the astronauts accelerate at the same rate as the ISS. Ergo, the astronauts are “weightless”, not in “zero gravity”. This condition can be simulated on Earth in the so-called “Vomit Comet” – an airplane designed to fly up and down along a certain path, to produce a weightless, free-fall when it falls.

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Posted in Science & Nature

Turing Test

Posted on by Jinavie

Alan Turing was a brilliant British mathematician who was pivotal in cracking the German Enigma cipher using a complex computing machine. He was highly influential in the founding of computing science. One of his greatest areas of interest was artificial intelligence. Like other computer scientists of the time, Turing predicted that machine intelligence was possible in the future with rapid development of computers. On this topic, he proposed the following question: at what point is a machine truly “intelligent”?

Intelligence is too complicated to define neatly in a single line. Therefore, here is a simpler question: can a machine do what we can do? For this, he proposed a thought experiment based on a party game known as the imitation game. In the imitation game, a man and a woman go into separate rooms. Guests then try to tell who is a man and who is a woman by writing a series of questions, slipping it under the door, then receiving a typewritten answer. If the guests cannot tell the two apart, the two win the game.

Turing modified this game into what is now known as the Turing test. He proposed replacing one person with a machine. A person and a computer are placed in separate rooms and are asked the same question by a judge. They then give a typed response. If the judge cannot confidently tell who is human and who is not, then the machine passes the Turing test.

Of course, the Turing test was not designed as a formal assessment and is merely a thought experiment. It has plenty of weaknesses, such as the fact that it only tests whether the machine is acting “like a human” rather than “intelligently”. For example, some computers have passed the Turing test by intentionally making typos to mimic human behaviour. Some have argued that machines that pass the Turing test do not truly exhibit intelligence, as it is impossible to tell if they fully understand the language or whether they are just running algorithms on symbols that the machine does not understand.

Regardless, the Turing test opens the door on the exciting yet frightening world of artificial intelligence and what the future holds for humanity.

Turing Test

(Image source: http://xkcd.com/329/)

Posted in Science & Nature

Dust Explosion

Posted on by Jinavie

When we hear explosives, we commonly think of chemicals such as nitroglycerin or gunpowder. But an explosion is essentially just a rapid release of energy and expansion of gases due to combustion. This means that if something is combustible – that is, it can burn – it has the ability to explode. However, certain conditions have to be met so that the combustion can be sudden and rapid.

Because of this principle, it is possible to explode dust or other powdered substances. If the dust is combustible (such as flour or coal), suspended in the air at enough concentration in a confined space, with sufficient oxygen and an ignition source, a dust explosion can occur. For example, coal dust explosions are a common threat to miners and there have been countless incidents where mills and factories have exploded with great fury due to a dust cloud forming from grain, flour, powdered milk and sawdust etcetera.

The reason why dust will explode in such a condition but not when it a pile of dust is lit with fire is that in a dust cloud, every dust particle is in contact with air. This massively increases the surface area of the dust relative to its mass, meaning there more reactions can occur. In this case, the reaction is oxidisation of the substance, leading to combustion. This is why the finer the dust or powder, the greater the risk of an explosion. Even substances such as wood or aluminium can create an explosion when finely powdered enough.

The greatest casualty due to a dust explosion was in 1942 when a coal dust explosion in a Chinese mine killed 1549 miners. Another famous case was in 1878 when the Washburn “A” Mill in Minneapolis exploded, leading to the destruction of the world’s largest grain mill and five other mills. This reduced the city’s grain production to almost one-half.

Posted in Science & Nature

Voyager

Posted on by Jinavie

In 1977, NASA launched into space two unmanned probes named Voyager 1 and 2 respectively. These probes were designed to study Jupiter and Saturn and were not expected to function past this point. The original Voyager mission officially ended in 1989 when Voyager 2 did a close flyby of Neptune. However, as of 2014, both Voyagers are still travelling ever onward into interstellar space, sending back crucial data about our solar system and what is inside it, along with beautiful photographs of the planets.

The two Voyager probes greatly outlived their expected lifespan and exceeded what they were expected to do. Thanks to the Voyager program, we now have a far better understanding of our own Solar System, such as the fact that it is asymmetrical, or that Neptune had three rings. Voyager 1 is now the most distant man-made object from Earth – with its closest neighbour, Voyager 2, being billions of kilometres away from it. Yet it continues to strive onwards into the unknown, exploring the depths of space all alone.

The Voyagers also carry a golden record on which scientists recorded pictures, sounds and music (such as Bach and Mozart) that represented scenery found on Earth. It also includes various languages, mathematic formulas, a representation of our Solar System and our DNA, anatomy and reproduction. It is meant to be a time capsule of Earth, for our future descendants or whatever else may be out there.

Posted in Psychology & Medicine

Dark Circles

Posted on by Jinavie

One of the most tell-tale signs that someone is extremely tired or sleep deprived is having dark circles around the eyes. The skin beneath the eyelids are very thin – almost a quarter of the thickness of skin elsewhere on the body.

During times of exhaustion, the skin becomes paler due to a number of factors. The paleness makes it easier to see the blood vessels running under the skin, which shows as a greyish-blue tint. The more vessels that can be seen and the paler the skin, the darker the circle appears.

Dark circles appear to be an inherited trait, most likely related to the thickness and transparency of your skin. It is also more common in people with hay fever, anaemia and liver problems. The only real treatment for dark circles is rest.

Posted in Philosophy

Eternity

Posted on by Jinavie

“High in the North in a land called Svithjod there is a mountain. It is a hundred miles long and a hundred miles high and once every thousand years a little bird comes to this mountain to sharpen its beak. When the mountain has thus been worn away a single day of eternity will have passed.”

~ Hendrik Willem van Loon

Posted in History & Literature

Maps

Posted on by Jinavie

Think of the world map. Most of you will think of the typical map where Europe and Africa are in the middle, with Russia dominating the Eurasian landmass and Greenland easily outsizing South America.

Mercator projection

The most common world map we use nowadays is based on the Mercator projection. Because the Earth is spherical and maps are two-dimensional rectangles, complex mathematics are involved to project the former on the latter by distorting the picture. The Mercator projection was created by Flemish cartographer Gerardus Mercator in 1569. The map was extremely useful for sailors because it depicted the curvature of the Earth in straight lines, making navigation much easier.

However, the Mercator projection severely distorts the size of each continents, meaning the image of the world we have in our heads is completely misleading. According to the Mercator projection, Greenland is as large as Africa, Alaska is as large as continental USA and Antarctica dwarfs every continent.

Gall-Peters projection

To solve this problem, the Gall-Peters projection was suggested in 1974 as an alternative as it correctly displayed the continents’ respective sizes. As you can see, in reality Greenland is significantly smaller than even Australia, Europe and Russia are much smaller than expected and Africa is an extremely large continent.

Dr. Arno Peters argued that the Mercator projection was a biased, euro-centric projection that harmed the world’s perception of developing countries. This of course, led to extreme controversy over the politics of cartography.

Africa vs Greenland

There are many other distortions commonly found in maps. Maps tend to enlarge the landmass of the own country subtly and some American maps go as far as placing the USA in the middle even if it means splitting Eurasia in half. Even though landmass does not correlate in any way with how well the lives of its inhabitants are, such distortions can be seen even nowadays. This shows that not everything you see is as it seems.

Posted in Psychology & Medicine

Ebola

Posted on by Jinavie

In 1976, an outbreak of a viral illness was identified in Sudan. Patients would present with symptoms of high fever, headache, vomiting, diarrhoea and a spotted rash, but would rapidly deteriorate in health. Within days, patients showed signs of decreased blood clotting, such as bleeding from intravenous line sites, having blood in their vomit and stool, or bleeding from essentially any bodily orifice. If untreated, patients would die within two weeks of shock (very low blood pressure), kidney failure or bleeding into the brain. The outbreak killed 151 people before it disappeared.

Later in the year, a headmaster at a school in Zaire developed a similar disease after travelling to the Ebola River. He died two weeks later. Soon after, people he came in contact with after his trip died of similar symptoms. The World Health Organisation investigated this epidemic and realised that the disease was caused by a new type of virus, which was named ebola virus. Due to its symptoms, the disease caused by the virus is named ebola haemorrhagic fever.

Since the discovery of the disease, occasional ebola outbreaks were seen in various parts of Africa, mainly around Congo and Uganda. Each time, the disease would rapidly claim the lives of hundreds of people and then vanish. This is because ebola virus was so effective in killing people (with a death rate of 90% in one outbreak), that it would kill the infected person before they spread the disease further.

The virus can be spread through any bodily fluid, including blood, tears, semen and sweat. Because of this, once an infected patient is brought into hospital, the disease can spread rapidly throughout the building and infect many patients and hospital staff if proper precautions are not taken. Fortunately, the virus is not known to spread when the patient is in the incubation period (when they are infected but have not shown symptoms yet).

The origin of the virus has been traced back to fruit bats (like many other serious viruses). Fruit bats have extremely powerful immune systems to protect their cells from the harmful metabolites produced by flying, allowing bats to harbour deadly viruses without succumbing to them. These viruses have also evolved to withstand the high temperatures produced by flying (which involves significant muscle work), meaning they can easily survive the high fevers they cause in humans. The transmission from bats to human in modern times is likely attributed to deforestation and humans encroaching into the bats’ native territory.

The current epidemic that originated from West Africa is the biggest ebola outbreak so far, having infected over 9000 people and claiming the lives of over 4500 people (October 14, 2014). However, this is likely a grossly underestimated number. The epidemic is focussed mainly in Guinea, Sierra Leone, Liberia and surrounding countries, but has infected foreign workers and volunteers who have been repatriated to be treated in their home country.

Despite a robust effort from the WHO to try and curb this epidemic, the infection rate continues to climb due to various factors, such as traditional funeral rites involving touching the deceased person’s body, which is still infective after death. There are currently no effective vaccines or treatments and the only thing that can be done is supportive treatment in an intensive care unit where the patient can be adequately hydrated and monitored. Like with most communicable diseases, the most effective treatment is preventing the disease from spreading through education, rigorous infection control protocols and improved healthcare systems in the affected countries.

Posted in Life & Happiness

Fear And Possibilities

Posted on by Jinavie

You are not afraid of the dark. You are afraid of what is in it.
You are not afraid of heights. You are afraid of falling.
You are not afraid of trying. You are afraid of failing.
You are not afraid of being in love. You are afraid of not being loved back.

The natural response to fear is fleeing from it. It is an instinct designed to preserve our life. But fear – like all emotions – is an irrational thing. Sometimes we fear something not for what it is, but what it could turn out to be. Therefore, the greatest fear is the fear of possibilities. Because we are scared of a certain possibility, we avoid the precipitant to prevent the possibility from happening.

But the possibility you are afraid of is merely one of many branches on the tree of possibilities. You might find the dark room holds a surprise party for you. You might find the height will not lead to a fall to your death, but show you the greatest scenery you have ever seen. You might find that the person you were too afraid of asking out may have been in love with you all along.

By not opening the proverbial box, you extinguish all of these wonderful possibilities. No matter how scary it may be, give the future a chance and take a shot.

Do not let fear steal your funk.

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Posted in Life & Happiness

Inside And Outside

Posted on by Jinavie

Each and every one of us have two selves: the self we truly are in our mind and hearts and the self we present to the world. Let us call these the inner self and outer self. For the most part, we know both our inner and outer selves quite well, because we know what we are thinking and feeling and we consciously control what image we show to other people. But because we cannot read minds, we usually only know the outer selves of other people.

Our inner self is somewhat difficult to change consciously as it is mostly shaped by our natural personalities, our upbringing and environmental factors such as life experience. On contrast, we have the ability to change how others see us through various ways. We wear smart clothing to suggest we are well-cultured, we tell jokes to give the image of a funny person and we emphasise our strengths while downplaying our weaknesses and insecurities to show our best possible side. Because of this, it is unfair to compare yourself (your “inner self”) to others (their “outer self”). The “perfect” person you are comparing yourself to may just be an outer shell shielding that person’s weak, insecure inner self that is no better than you.

We all have our own demons and insecurities, but no one wants others to know as all we see in society are strong, charismatic, charming outer selves and we seem so weak in comparison. In the end, we all live behind masks to try fit into a world full of masked people, too afraid of showing our true selves and being hurt.

Then how can we truly connect if we are all pretending to be different people? Always remember that others are just as afraid of lowering their mask as you are. You cannot expect the other person to open up to you first when you are not prepared to yourself. On the other hand, you cannot be hurt when they are reluctant to open up just because you have. To show your inner self means leaving yourself to be vulnerable, so it is understandable for people to take time for it to happen. All you can do is to let yourself be vulnerable first and show the other person that you are just as weak and scared as they are. That is the cost of connection.