Shadow of the Moon

Originally published in the Informanté newspaper on Thursday, 24 August, 2017.

On 21 August 2017, a rather historic event occurred – a total solar eclipse occurred that was visible across the entire contiguous 48 states of the United States of America, across a narrow corridor about 110 km wide. This is the first time since June 8, 1918 that such an event has occurred, and only the second time in the history of the United States. However, the previous time a total solar eclipse exclusively made landfall on those land was back in 13 June, 1257 – several hundred years before the US was even founded.

Here in Namibia, we’ve also not seen any total eclipse since the founding or our nation – but to be fair, it’s been a scant 27 years. Not to worry however – shortly after our Nation’s 40^th birthday, we will be able to witness one. On 25 November 2030, at 6h24 in the morning, just after sunrise, the sun will seem to start going out again. By 07h18, the sun will be completely obscured by the moon, and Windhoek will be in the moon’s shadow. At 07h20, we’ll breathe a big sigh of relief as the sun becomes visible again, and full visibility will be restored by 08h21, when the sun will appear normal again.

How can I possibly know this? Why, science! It works! Of course, it helps that humanity has been observing and recording eclipses for over 2000 years. It became much easier with the invention of writing, which is why it was the Mesopotamian civilization that first determined the length of a Saros cycle – or 18 years, 11 days and 8 hours. This is the amount of time it takes for the sun, moon and Earth to return to the approximate same relative geometry – quite simply, it’s the time between one eclipse and the next when the three celestial bodies line up in the same straight line. 

As a result, they were able to determine with relative accuracy when an eclipse would occur – but not why or how it does. First the Greeks entered the scene – they felt you cannot understand something unless you can explain it. Their observations established that that planets and the moon where spherical, and thus, that the eclipse is that shadow of the moon cast by the sun onto Earth. Of course, the Greeks had one fundamental flaw in their approach – the assumed the Earth was the centre of the universe. A perfectly understandable assumption, for it is one we all tend to make when considering our lives. 

The same kind of work was being done in China, and it is even speculated that the Mayans measured eclipses, though their data was lost due to the Spanish Conquistadors. But in 1543, that changed due to the work of one Nicolaus Copernicus, in his “De revolutionibus orbium coelestium,” or “On the revolution of heavenly spheres.” Here he postulated that unlike what was assumed by Aristotle and the other Greeks, the Earth actually orbited the sun. But Copernicus’ model still had significant shortcomings. But soon, they were addressed…

For in 1687 a young man by the name of Isaac Newton published a work known as the “Philosophia Naturalis Principia Mathematica” or “The Mathematical Principles of Natural Philosophy.” Not only did this introduce to the world Newton’s Laws of Motion, and his Theory of Gravity, but the this volume of his treatise, “De Mundi Systemate” or “On the system of the world,” he applied the propositions he made earlier to the motions of the planets and moon as observed in the solar system, and ushered in modern astronomy. 

By the time telescopes were invented, these calculations could be done with much greater accuracy, and by the 1700’s astronomer Edmond Halley even published a path of a coming eclipse in the hopes that people would not panic when it happens. It ushered in the era of the modern eclipse watching. In 1824, Friedrich Bessel invented the method used for calculating the occultations of eclipses – or the movement of the shadow and its shape over an irregular object such as the earth, allowing for calculations to show the precise location of the shadow accounting for latitude, longitude and elevation above sea level. 

Of course, these methods all assumed that the moon was a perfect sphere – and today we know it’s not. Charles Burleigh Watts spent most of the time during the 1940’s to 11963 to mapping the variations in the moon’s surface, allowing predictions to get even more previse, as now the shadow wasn’t a perfect oval. NASA’s Lunar Reconnaisance Orbiter was later used to refine Watt’s work, as it was able to capture the moon’s topography in much greater detail than would have been possible from the surface of the Earth.

So how precise is the predictions now of eclipses – specifically the one I mentioned for Namibia, due in 2030? Well, not 100% - after all, we still don’t know all the variables quite that precisely. Neither the moon nor the Earth is perfectly round, and that ‘squashiness’ is only known to a certain degree of precision. Furthermore, the movement of the Earth and the moon are not constant. While the Earth revolves around the sun once every 365.24219 days and the moon around the Earth every 29.530575 days, a number of forces could speed or slow it by minute fractions, throwing calculations off. 

But even so, this means the calculations are at most a few seconds off. Back in 1932, the New York Times warned astronomers that the eclipse due on 31 August 1932 was the last one that they could reliably see from US until August 21, 2017. I propose this – save this paper, and we’ll have a discussion on Monday, 25 November 2030 at 07h21 about the predictive power of science.

Food, Waves and Particles

Originally published in the Informanté newspaper on Thursday, 17 August, 2017.

Every so often, I hear someone confuse ‘radiation’ and ‘radioactivity.’ These are two wildly different concepts, but they’re usually conflated in an attempt to convince someone that, say, microwaving food is unhealthy, because it uses radiation to heat the food – “How can that be healthy?” Fortunately, I do not deal in emotional appeals to fear, but rather to the facts at hand. 

Radioactivity, as we all know, is the process by which an unstable atomic nucleus loses energy by emitting radiation, by way of alpha, beta or gamma radiation. So what is radiation? Simply the emission or transfer of energy in the form of waves or particles. Alpha and Beta radiation, as you might recall, are particles that are radiated, while Gamma radiation is electromagnetic radiation with high energy. This is what is known as ionizing radiation – radiation with high enough energy to free electrons from atoms and molecules, and thus ionizing them – allowing different chemical reactions to occur. 

So what about microwaves, then? Well, not all radiation that occurs occur due to radioactivity – and not all radiation is ionizing radiation. Simply put, food is ALWAYS cooked via radiation – thermal radiation! Microwaves are in fact a form of electromagnetic radiation of a lower frequency than thermal radiation just above the radio frequencies and below visible light frequencies. The wavelength of microwaves are between 1mm and 33cm.

How does it work, then? Well, food is heated by passing the non-ionizing microwave radiation through it. In consumer-grade ovens, this is typically electromagnetic waves at a wavelength of 12.2 centimetres, while industrial microwave ovens operates at 32.8 centimetres. During this process, water, fat and the rest of the food substances absorb this energy via the dielectric effect. In essence, water molecules are electric dipoles, with a partial positive and partial negative end. As these waves pass through them, they try to align with it, and as the microwaves alternate, this causes the water molecules to rotate. These rotating water molecules vibrate, putting other molecules in motion and causing them to vibrate as well. This molecular vibration is commonly referred to as ‘heat’.

A common misconception is that microwaves heat food from the inside out – this, however, is not the case. Microwaves face the same issue as normal thermal radiation in penetrating dense materials, and thus also cook from the outside in. The penetration depth varies depending on the material, but generally it only penetrates for about 1cm in meats and vegetables, to about 2 to 5cm in water and bread. 

So what does this all mean for our food? Well, oddly enough scientists have found almost the opposite of what you’d expect – microwaved food is HEALTHIER! In terms of carcinogens, microwaved food contains a lot less heterocyclic amines, which are usually found in meats after grilling or braaing, and less is created when meats are cooked at less than 100 degrees Celsius or with a shorter cooking time. In fact, if meat is precooked in the microwave before they’re grilled, it could reduce HCA’s between 3 and 9 times in the final product.

This result is also found with polyaromatic hydrocarbons as well as nitrosamines, two other carcinogens.  So microwave cooking tends to produce less carcinogens, but what about other nutritional effects? Well, studies showed that in terms of proteins, the nutritional value remains much the same. In vitamins and minerals, however, there again appears a distinct advantage. Due to shorter cooking times, and the fact that vitamins and minerals are absorbed by water when cooking, microwaved food retained much more of vitamins B & C compared to traditional cooking, as well as more phosphorus and potassium. 

Clearly, the drive by some to demonize microwaves simply due to fear of association with ‘radiation’ is ill-founded and are not backed up by scientific studies, and show that it might actually be healthier. True, microwave cooking does have some dangers, and I would not, for example recommend microwaving eggs, due to pressure build up in the shell. Microwave ovens usually go ‘ding’ when there’s stuff to eat, but in this case, it’s not pretty when they blow, and you’ll have to clean up for quite some time. 

Of course, it’s not just microwaves that get people up in arms. There’s also ‘Irradiated food!’ If you’ve read this far, you’ll probably realise what comes next – it’s not dangerous either. In fact, it could be said that it’s helping world hunger. In this case, however, when they talk about irradiation, they’re not talking about non-ionizing radiation. Oh no, this is actual ionizing radiation. 

Food is passed through a food irradiation machine that blasts it with energetic particles or waves, causing collisions with particles and breaking chemical bonds – specifically, those of cells and targeting DNA and RNA, limiting cell division and limiting reproduction. Why is this done? Why, to kill microorganisms, kill invasive pests and to delay or eliminate sprouting – effectively preserving food much longer, and allowing food to travel much further, allowing you to have a wider variety of food on your table. Even in this case, the radiation is carefully measured, and does not make the food radioactive – after all, exposing food to light does not make food emit light, does it? 

So next time someone tells you that microwaving food with radiation makes it radioactive, ask them why they do not glow in the dark, as they’re irradiated daily with visible light. As for you, you can continued to heat or cook food safely in your microwave, and eat food with an irradiated label on it, safe and secure in the knowledge that you’ll be healthier, less prone to cancer, and potentially getting greater amounts of vitamins and minerals, without having to worry about the pseudo-scientific mumbo-jumbo that everyone keeps trying to peddle to you.

To Count A Vote

Originally published in the Informanté newspaper on Thursday, 10 August, 2017.

With the news being dominated by politics over the last few weeks, the time has come again that we must delve into the subject at hand. In a democracy, politics is intimately tied with voting, so it seems logical to start there, and examine Namibia’s dual-system of voting – after all, it is from there that our republic derives its legitimacy. 

In our national assembly, Namibia uses a proportional representation system of voting. The basic idea of proportional representation is to reduce the disparity between a party’s share of the vote, and the number of seats it has in parliament. In some nations, this means a country is divided up into several electoral constituency, which each elect several members to parliament. In Namibia, however, the entire country is designated as a single constituency.

Proportional representation have several advantages above other forms, such as the first-past-the-post system used in the United Kingdom and the United States. Firstly, it is the most accurate way to translate the national vote percentage into seats available at the assembly. It also encourages parties to campaign nationwide, instead of only in regions where the party is weak, as all votes go towards seats in parliament. This indirectly stop regional parties from overpowering minority parties in a region, like the Scottish National Party does in Scotland in the UK.

The access proportional representation provides to minority parties is especially important, as even with just a few votes, they can gain access to representation. This promotes inclusion, which provides stability to society, builds more socially representative decision making bodies and provides role models (elected representatives) to otherwise marginalized groups. With better representation in the public sphere, this results in a more transparent power-sharing system between different interest groups, as parliament is usually a public forum, and reduces corruption inherent in power-sharing behind the scenes. 

Namibia, however, is not purely proportional representation – we use Party-List proportional representation system. This by necessity is even better for minorities, as people vote for parties, and with public party lists, the parties have to ensure everyone is represented. This means for a party to appeal to all, the party list has to include a wide variety of members, including those of minorities. 

In particular, this is advantageous to get women represented, as lingering sexism in the underlying population is countered when a party doesn’t have to put a male representative forward to court sexist voters to ensure a win. This has allowed Swapo to institute the Zebra policy during the last election, meaning that for the first time, women in Namibia could have the same 50% representation in the National Assembly. This means the gender balance in parliament resembled that of the general population for the first time in the country’s history. 

Proportional representation also means there are very few wasted votes, as most votes go toward a seat in the National Assembly. During our last election, this means only 10 427 votes were wasted, or 1.3% of the total votes cast did not result in a party having a seat in parliament. But as always, it’s not all sunshine and roses with this system.

In particular, proportional representation also gives a platform for ‘extremist’ parties, as they can now have the floor in parliament disrupt proceedings. We’ve seen the effect this can have in our neighbour South Africa, and even in the embarrassment of the UK when their United Kingdom Independence Party got seats in the European parliament. 

It is also difficult for voters to enforce accountability by throwing a particular person out of office. With the list based system, this usually means that the party itself can continue to place an unpopular person in a position of power, even if this is not what the voters desire. For them to effect change, they have to throw an entire party under the bus – sacrificing all those who they actually like. 

It also results in a weak link between elected representatives and the voters – after all, there’s no specific representative that is voted for by their specific region – and even if someone is assigned, it will be by the party, not the voters themselves. As a result, voters find it much more difficult to approach government. It also means that it is difficult for independent candidates to make themselves available for election, as voters vote for a party, not a particular person. Some type of party structure is always required. 

Finally, a disadvantage of the list-based system is that is causes the entrenchment of power within the party. Since position is determined by a person’s rank on a party list, they have to remain in favour with party leaders if they want to retain their position. As a result, party members with different policies than that favoured by leadership will often be marginalized, while those most skilled in brown-nosing tend to rise to the top. Perhaps even more concerning, is the fact that in a list system, when number 5 on the list, for example, unexpectedly dies, or for any other reason, it is number 75 on the list that moves up – and rarely is number 75 an adequate replacement for number 5. 

The rest of the disadvantages of proportional representation has been neatly avoided by Namibia – coalition governments, disproportionate power to minor parties due to their kingmaker status, etc. – simply because be use proportional representation to elect the legislature, but a plurality first-past-the-post system for government – the presidency. Our semi-presidential system thus allows us to avoid the pitfalls we’ve seen South Africa fall into. Yet, this system is not itself without its problems – that, however, is a discussion for another time.