Insects are the strongest organism

So recently I have been wondering what makes insects so strong. No really, they may not lift and pull the biggest weight in absolute terms. But those tiny beasts can sometimes carry a hundred and sometimes even a thousand times their body weight. Meaning insects have the most efficient body structure and use of muscle when it comes to doing work.

Take the Onthophagus taurus – dung beetle if do not speak french(!) – the strongest males of this species can sometimes pull up to 1,140 times their body weight. To give you an idea of this feat, we can compare how this fares against the strongest males of our species. The dung beetle dragging around something that is a 1000 times its body weight is a more impressive feat than Brian Shaw (2015 winner of World’s Strongest man strongman competition) dragging around a blue whale.

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That’s correct, a standard blue whale is only 740 times as heavy as Brian Shaw.  So imagine a grown powerlifter dragging around a whale and not being impressed because you just saw a dung beetle drag around a large ball of, well, dung.

This is not an ability exclusive to beetles (although it is contender for an insect world record).  Another insect that is all a serious lifter is a group of species of ants known as leaf cutter ants. These can carry more than 50 times its bodyweight in their jaws.

This is equivalent to a human lifting a truck with his teeth.
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What makes these feat possible?

It lies at the heart of a mathematical/slash physics principle known as the square cube law.

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If you bear with my primary-school diagrams, we’ll start with the basic principle.

Scaling length of each side of the cube by a factor of 10 makes it 10 times as high/long/wide. However, its surface area increases by a factor of 100, whilst its volume increases by a factor of 1000. We can then see that the volume and surface area are proportional to the cube and square to the length of the object.
The same is true for spheres. If you confer to amateur diagram number two, you’ll see this happening. It might not be as obvious because the sphere has weird number multiplying the cube of the length and the square of the length (which is equivalent to the radius), but we can just call that a constant of proportionality that makes the equation balance. The volume is still proportional to the cube of the length.

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This can be generalised to more weird shapes, or rather shapes you are more likely to encounter in real life. The volume and surface area of most shapes follows the cube and square law, the only thing that is different is the value of the weird number that appears in front of the l^3 and l^2.

So why am I dragging you back to tedium of geometry?

Unlike abstract 3D shapes, real physical objects have a weight that grows with volume. How heavy something is is directly proportional to volume, making it directly proportional to the cube of the length of the object.

Also of particular interest in this context is that for biological objects (my fancy way of saying, things that are alive) have muscles. The strength or force that these muscles exert or handle depends on the cross-sectional area of the muscle. A larger cross-sectional area contributes to a stronger muscle. Obviously there are lots of factors at play, such as leverage, the type of muscle finer and all sorts of other biological reasons that I do not know. But comparing two muscles with different areas, but otherwise identical, one will find that the muscle with larger area is stronger.

To put it simply, if you enlarge an object whilst still maintaining the same shape that object will face a continual decrease in the surface area to volume ratio. 

The reason why such a relation between strength and area exists is beyond the scope of this post. Just treat it as a an experimental fact.

It may not look like it but we have gathered all the information we need to answer the question why insects can lift loads that far exceed their bodyweight.

We have all the experimental facts:

  • The strength or force exerted by an organisms muscles is proportional the cross-sectional area, which is in turn proportional to the square of the length of the muscle. Making the strength of the muscle proportional square of the length
  • The weight of an organism is proportional to its volume and therefore the cube of its length.

Okay, so now we do a common thing in physics and take away the the two forces from each other. This is called balancing the forces. It is a sort of comparison we can make using maths to see which one is larger.

So bear with me and let’s do some maths.

F_{muscle} = A l^2
F_{weight} = B l^3

Where F is force and l is the length of the organism. So now let us compare the two forces, we can do this by finding the the ratio of the two forces. This gives an indication of the relative strength of the two forces.

F_{relative} = \frac{A}{B} \frac{1}{l}

This gives a mathematical function, which depends on the variable l which is length of an organism.

What happens to the ratio as we increase the size and thus length of the organism. Fortunately, we are mathematicians so we do not have to actually go out and get ants, cats, dogs and lions and tell them to lift weights. We can plot the value of this function for every value of l. What we get is this.

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You can see that for small organisms (small l) the ratio has an incredibly large value, whereas for the larger organisms (big l) the ratio drops away getting smaller and smaller.
Of course this is a very simplified analysis and there many other factors one can include that will change how the function drops as l increases. But the principle would remain the same. The force exerted by muscle compared to the bodyweight grows very large as organisms grow smaller and smaller.

This is the principle behind why insects can lift loads hundreds and thousand times their bodyweight. It also means if you were shrunk down you could jump distance several times larger than your height.

Does this mean it is better to just to be smaller? (Do not even go there 😉 )

The square-cube law affects more than an animals capacity to lift heavy things.

The metabolic rate also falls victim to this law. I’ll show you how the rate depends on the size of the organism. Of course, with anything biological the factors defining and determining the metabolic rate are a bit complicated.
But we are physicists, so we can simplify it to mean the battle between the energy we expend and the energy we consume.

So consider a horse, which is standing very still. So still in fact that its only energy expenditure is the heat loss from its body.
What we will try and calculate is the minimum energy the horse needs just to maintain its body temperature, how much food it needs to metabolise to generate enough heat to keep a steady temperature.

Of course in this consideration we will be ignoring all the complicated details. These are, that their temperatures aren’t uniform across their body, plus, animals are generally hotter the deeper you go in their body. You know where the warm blood is.
So any heat that radiates away is going to be absorbed by the various layers of tissues on its way out.

But, what won’t change is the general trend (this is the basic physics law we will be using) is that the amount of heat an object radiates away depends on the surface area. The heat Q is proportional to the surface area of the object.

Q \propto A \propto l^2

This is the minimum energy the horse and any animal needs to consume just to stay alive. 

Now suppose we do an ‘experiment’ with the horse. We shrink our horse down, in such a way that its density remains the same. Meaning the shrinking horse will weigh less by the same fact we reduce its volume by.
The density \rho can be written as

\rho \propto \frac{M}{l^{3}}

Where M is mass of the horse. Since \rho has to equal some number that does not change, we can write the following.

M^{\frac{1}{3}} \propto l

So combining our equations for Q and l we get the following,

Q \propto l^2 \propto M^{\frac{2}{3}}

If you did not follow the maths, what the result states is that the energy consumption increases with the mass (but in a slightly weird way as opposed to a direct proportionality).

But what is more interesting or more informative is a sort of relative consumption rate.

To find this, we divide Q by the mass of the animal.
Why?

Because doing so will show how much the animal needs to eat compared its bodyweight.
So I went right ahead and divided Q by M. I know. Daredevil.

\frac{Q}{M} = Q_{relative} \propto M^{-\frac{1}{3}}

This is just a mathematical function is similar to the one we had above about the muscle strength. It blows up as M gets smaller and smaller. This shows that smaller animals needs to eat more and more just to stay alive due to their hyper fast metabolic rate.

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And infact this is what we see with the shrew (amongst the smaller mammalian critters). Shrews have to eat nearly every few hours, and even eat beyond their bodyweight per day because the digest food so quickly.
So it isn’t always advantageous to be small. Larger animals like us have the luxury to not spend most of our time eating (though many have tried) to stay alive, leaving us open to pursue other activities.

You could jump very high but you would have to eat all the time. Doesn’t sound too bad actually.

As a last bit of deliberation, this Q_{relative} will place a lower limit on how small something can get. After a certain point M can’t reduce further; there just isn’t enough time in the day for gorging that could match the metabolic rates the mathematics suggests.
This is why you do not see mammals smaller than a shrew. It is physically impossible, to get any smaller and chemistry and digestion habits would have to change comprehensively changed to counteract the effect of energy consumption via heat loss.

Also as a final final deliberation. The calculation I presented to you was a super simplified version. A more comprehensive one resulted in reproducing what is knows as Kliebler’s Law. This is the experimental observation in 1932 that the metabolic rate is proportional to M^{\frac{3}{4}}. Notice the different exponent on M.

A couple of physicist and biologists in 1997 successfully derive a different law where M is raised to the power of 3/4 rather than 2/3. They did this using the concept of fractals, basically considering all the complicated stuff I ignored.  This included the fact that the tissues in large organisms have a supply problem. Some cells are too far away to receive the same level of oxygen from the bloodstream as other cells in the body. Kliebler’s law can derived by treating mammalian distribution networks to be “fractal like”. You can read more about it here : https://universe-review.ca/R10-35-metabolic.htm

The power of a fundamental law of nature

I hope I have shown you why insects are the strongest organism. But what I really hope to have shown you through this exercise is not much to do with insects or horses.

It is to appreciate the far reaching consequences of a mathematical truth. Most of the animals on Earth including us, are shaped and sized the way they are because of physical and mathematical limitations.
The square-cube law affects how small or big or bulky something can be. A tapeworm can be enormously long but is forced to be thin, because oxygen and food has to penetrate directly through its skin, owing to where it feeds from.
Some animals have a maximum size, it is impossible for that animal to grow any larger (ignoring marginal differences). This includes insects,if they were any larger they would be crushed under the weight of their exo skeleton.

Given this incredible variety of beasts with such complicated features and evolutionary histories, it is astounding that at its most fundamental level there are only a few mathematical and physics principles governing the amalgam.

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What Tesla did and did not do

There seems to have been a sudden resurgence of hype surrounding Nikola Tesla in popular culture. His known and unknown accomplishments and apparent inventions have raised him on a pedestal just two metres shy of godhood. However, as I read through much of the passionate articles, posts, videos about Tesla it becomes apparent; the large amounts of misinformation that is spread throughout the inter webs, surrounding Tesla and particularly his feud with Edison. Although, it makes for a nice narrative about conflict between the two – in many ways similar – men, it is counterproductive to science, and undermines the nature of invention.

Having said that, Tesla still remains one of my heroes and I am one of the guilty that had previously accepted the various false information about Tesla.  I am not going to go on a Tesla bashing rant, no one can deny his genius and his incredible passion and talent and effectiveness on whatever he worked on. He remains the quintessential geek and a role model to many. But, the misinformation about what he did and didn’t do sort of implies the scientific community wrongly shunned him aside and denied the world his outstanding discoveries. There are several Tesla demagogues, in particular cartoonist The Oatmeal, makes large passionate statements that are almost close to Tesla propaganda. (Okay he is a comedian, so much of it is exaggerated). But it has fuelled many conspiracy theorists that readily back Tesla as another underdog put down by the ‘man’.
Whilst he may’ve been brilliant, some of his incredible claims simply lacked credibility.

I will go through all of his attributed discoveries and inventions and add a little more perspective than “Tesla did it all!”
But first a little about Edison and Tesla.
Edison vs Tesla
Whilst The Oatmeal and many others antagonises Edison for the purposes of the narrative. I don’t think the author will deny that both men were brilliant, and geniuses in their own right.
Edison had hired Tesla to work with him on the recommendation of another colleague.
They were in a lot of ways different but similar in others.
Firstly there was a clash of methods: Edison was not formally educated in the field in the same way Tesla was, so he relied on what Tesla would have considered tedious experimentation to investigate certain properties. Whilst Tesla was an emotionally driven dreamer with years of engineering training, which allowed him to work out theories before physically implementing them. Both men criticised the methods of the other, but each method worked for them.
Each man was starkly different in nature: Tesla was a germaphobe and fastidiously clean, whilst hygiene was slightly lower down on Edisons list of priorities.
However, they were also similar in some regards, they were both egocentrics  and highly concerned with their self image. Contrary to popular belief, Tesla was just as business minded as Edison, he knew he had to promote himself to be considered in a higher regard than Edison. If you begin to read at all about history of technology at the time you will find that inventions and ideas spread like wildfire from as far east as Hungary and Moscow, to the U.S. For someone like Edison or Tesla it was important to keep up the show and wizardry to captivate the public. And they both did that very well. In the ruthlessly competitive environment of New York City the game was, (and still is) about fame/success at any cost.
Here is a picture of Tesla being a ‘showman’.

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Yes, Tesla left Edison’s company short-changed and frustrated but he wasn’t the only one who left like that, mainly because Edison was stubborn. But, Edison’s shortcoming should not bolster Tesla’s achievements or fuel false achievements. Just because Edison may have been a bit of a douche does not mean Tesla wasn’t, or serve to prove Tesla was better of the two.
Yes, Edison and his PR team did electrocute Topsy the elephant and Tesla would never have done so to his credit.
But the fault was not all Edison’s, in the social climate at the time there was very little regard for the welfare of animals. It was certainly a dark time in history for animals. The general public did not balk at the idea, but yes Tesla did and for that he was ahead of his time. But Edison cannot take the sole blame for a bad public attitude towards animal welfare.

Finally, whilst Edison stubbornly and wrongly supported DC throughout the ‘War of Currents’, his influence in General Electric was close to null. General Electric was readily accepting AC power and Edison was cast aside by the board for not being a team player. Tesla was fired from Westinghouse for a similar reason.

  • Invented AC currents
    The first hand-cranked AC generator was developed by Hippolyte Pixii in 1832. And conceptually and developed in principle by Micheal Faraday. The development of AC, like the history of anything, then followed a long and complicated path and several people contributed to it. Yes, Tesla did contribute to the development of AC and was a factor in the ‘War of Currents’ that would bring AC to mainstream use. Yes, he built an induction motor and filed a patent in 1888, for which he gained the support of George Westinghouse (who later hired him). At a public presentation Elihu Thomson (another electrical engineer) and Westinghouse (also an engineer) both thought that Tesla had potential. Thomson ( the company that later became General Electric) offered him a lower position to start with. Tesla’s ego lead him to decline the opportunity. Lucky for him though, later on Westinghouse offered him a position with his already established team of engineers working on AC.
    Yes, he did improve AC power greatly. But he had several contemporaries. Tesla and his Westinghouse coworker Oliver Shallenberger developed the transformer to work with Tesla’s 2 phase AC systems. But Tesla’s egomania prevented him from properly thanking Shallenberger.
    He was not the sole inventor, in fact the induction motor designed by a guy called Benjamin G. Lamme is what we use today, not Tesla. Yet he remains unsung. Where is his comic Oatmeal?
    If you are interested in the actual invention history than a human conflict you can read up on it here: http://edisontechcenter.org/AC-PowerHistory.html
  • He invented Radio
    Guglielmo Marconi won the Nobel Prize in Physics for his Radio Telegraph system.
    The story goes that Tesla responded to Marconi’s achievements by saying that he had done so with 17 of his patents. But what you must understand about Tesla is that he was an egomaniac and a tremendous narcissist, one that could parallel Edison and he made several of these claims.
    Tesla did do groundbreaking research in AC and may have experimented with wireless transmission of power but these were overshadowed by more important experiments done by the likes of Heinrich Hertz, Oliver Lodge, Guglielmo Marconi, Karl Braun – the latter two winning the Nobel prize in 1909.
    Even if Marconi had used Tesla’s research to make a practical version this does not mean Tesla ultimately invented radio. If you are going to use that argument, then the true credit must go the James Clerk Maxwell, the guy who first theorised Electromagnetic Waves, or Hertz who first produced radio waves.
    This claim is also made slightly absurd since throughout 1919 Tesla refused to believe Radio Waves existed.
    There is also the issue of the case in which United States Supreme Court supposedly overturned Marconi’s patents and proclaimed Tesla as the true inventor. The case did not actually try determine the “inventor of the radio” as various articles (like the The Oatmeal) would claim. You can read up on the actual case here, if you are interested in the fact. https://supreme.justia.com/cases/federal/us/320/1/
    It was a financial compensation case, during WW1, the US govt. knowingly infringed upon numerous radio patents (not even original radio transmission and reception devices, just later improvements concerning 4 high frequency circuits), in hopes of paying out compensation after the war.The 1943 decision didn’t overturn Marconi’s original patents, or his reputation as the first person to develop practical radio communication. It just said that the improvements of the initial invention, was fully anticipated by patents issued to Oliver Lodge and John Stone Stone. (Yes that is his name, I didn’t accidentally type that twice)Read through the entire syllabus and you’ll find not one mention of Tesla.
    Tesla, as brilliant as he was, was deeply misguided about a lot of physics. He refused to accept the concept of electrons as subatomic particles. Similarly, he referred to radio as ‘fake wireless’, when you look at what he wrote it is clear he did not have a solid understanding of Electromagnetic Physics and he didn’t even know that he was wrong.
    In 2001, Professor of Electrical Engineering Paul J. Nahin wrote in his book The Science of Radio, “He was also a force in the early development of multi-phase ac power distribution. The unit of magnetic flux density is named after him. Others, however, not satisfied with Tesla’s true achievements, find it necessary to claim he did all sorts of other things as well (which, curiously, not even the full scientific might of the Pentagon can duplicate, such as Tesla’s famous 1934 ‘radio death ray’ that he said could destroy 10,000 planes 250 miles away and annihilate, in an instant, an army of 1,000,000). It seems more likely that Tesla, unable to repeat his early triumphs, looked for other ways to get back into the limelight he so coveted; he began to make astonishing claims to wealthy potential patrons who, knowing next to nothing of science, could be easily dazzled. One of these claims was that he had ‘invented radio.’
    Tesla was, without question, very skillful at generating large, noisy sparks with the aid of step-up transformers tuned to resonance (the famous Tesla coil) and he seems to have really believed that, since Marconi used sparks in his wireless work, then he too must be a wireless pioneer. There is, however, not a shred of credible evidence that Tesla did anything more than just talk about radio (in 1901, for example, he claimed that two years before he had received radio signals from Mars), and nothing in the historical record supports his grandiose claims. It is clear, in fact, from what he did write, that Tesla actually had only the slightest (if that) understanding of electromagnetic radio physics; he claimed, for example, that “his” electric waves were both immune to the inverse-square law and that they traveled faster than light.”
  • He invented radar
    I am not even sure how this myth came about but, if you are inclined to do so you can read through the history of radar and find not a single mention of Tesla. If you do it may be just be that he again raised commotion about how his thoughts on the matter preceded before anyone.
    Frankly, Radar works with micro- and radio waves, phenomenon which Tesla refused to believe exist or to be of any great utility.
    You can read extensively about the history of radar here : http://www.aps.org/publications/apsnews/200604/history.cfm
    The patent was awarded to Sir Robert Watson-Watt, and there were several who preceeded before him such as Heinrich Hertz, Marconi, German engineer Christian Huelsmeyer, Edward Victor Appleton, and Russians who developed a radar system to detect German planes in 1934.
  • He found a way to deliver free electric power
    I shall admit The Oatmeal did not focus on this as the author realised this claim was made when Tesla was suffering from a mental illness of some sort and rightly did not focus on it. But this myth still seems to have persisted. Many Tesla fans claim a conspiracy theory stopped Tesla from making “free” electric power distribution wirelessly. This of course is a fallacy, during his time and still today we are constrained to using energy from the earth. As long as we are energy will never be free, it is a limited good so it will always have a price. Even renewable energy needs infrastructure and people to man the infrastructure and you need to pay to people to man it thus harnessing energy will always have a cost.
    Not to mention, his idea of sending it wirelessly through some form of radiation would be hazardous to wildlife and humans. We debate about the danger of cellphone on human brain, which have a low power level. So you can imagine powering the entire planet using this kind of radiation.
  • He thought up the idea of hydroelectric power and built the first hydro-electric generator.
    Yes, he was involved in the Adams Power station that harnessed the enormous power from Niagara falls and transmitted it to the booming city of Buffalo. Two major electric giants collaborated in this effort: General Electric (founded by Edison) and the Westinghouse Electric Company. Tesla was one of the engineers working for Westinghouse, and yes the plant and generators were based on Tesla’s 25Hz AC Power system.
    But the efforts at Niagara falls were part of a larger team; Tesla’s was not the only mind at work. Thomas Evershed (water power engineer), Benjamin G. Lamme (electrical engineer) were one of the many engineers who worked there. In fact, Lamme improved on the designs of Tesla (as they kept burning up on tests) which is fine because that is how technology progresses.
    Interestingly enough, Westinghouse won the power generation contract by undercutting General Electric by $601,000, even though GE was offering a three phase AC system that was made possible by an independent contractor C.P. Steinmetz.
    Moreover, this was not the first hydroelectric plant. In 1879 Jacob Schoellkopf had adapted electrical technology and created turbines and the first hydro-electric generators.

I could go on about several more supposed inventions but I do hope you are beginning to see common theme. A lot of Tesla’s contributions to many fields were preceded and succeeded by other fellow inventors that are just as unknown as Tesla was.

The Oatmeal bashed Edison for improving upon the work of 22 people before him when inventing the light bulbs. But that is exactly how invention and innovation happens, each person adds their little contribution and the thing gets slowly built up. Many of Tesla’s achievements are of a similar nature. A single person can’t be the sole inventor or dicoverer of anything, they will always build on previous work. As a result a lot of influential people are forgotten by the general public. You might know of Newton (also a known douche), but do you about Kepler who preceded him? You know about Einstein and his theory of special relativity but do you know about Lorentz who derived the transformation equations that Einstein used?

Tesla is my hero and is amazing, but not because he supposedly invented the modern world. But because he was incredibly passionate about his subject to the point of obsession, and that passion inspires and fuels mine. He was genius, he did know 8 languages and had a phenomenal eidetic memory that allowed him to recite entire novels. He was an important engineer and worker in science and for that he should be celebrated, and science has immortalised him in a way by naming the unit of Magnetic Field after him.
But to claim he invented everything just because he had thoughts about various subjects is like claiming Da Vinci invented the helicopter.

I’d just like to leave this quote about the nature of invention by Mark Twain.
“It takes a thousand men to invent a telegraph, or a steam engine, or a phonograph, or a photograph, or a telephone or any other important thing—and the last man gets the credit and we forget the others. He added his little mite — that is all he did. These object lessons should teach us that ninety-nine parts of all things that proceed from the intellect are plagiarisms, pure and simple; and the lesson ought to make us modest. But nothing can do that.” – Mark Twain

P.S – I do not mean to completely bash The Oatmeal, it is a really funny comic which I do enjoy reading from time to time. I just wanted to sate the rumours surrounding Tesla and a few of his statements seems to have sparked them, to my at least. I loved his efforts of saving Tesla’s old laboratory and turning it into a museum. I may be wrong in a few place, but I am unknowingly so please be kind in pointing out my errors.

References: 

http://www.aps.org/publications/apsnews/200604/history.cfm

http://earlyradiohistory.us/tesla.htm (Where I also got the image with insane sparks)

http://www.niagarafrontier.com/power.html#Sch

http://www.biography.com/people/nikola-tesla-9504443#synopsis

http://library.buffalo.edu/libraries/projects/cases/niagara.htm

http://edisontechcenter.org/Niagara.htm

https://minystories.wordpress.com/2013/04/29/niagara-falls/

http://mentalfloss.com/article/30140/acdc-tesla–edison-feud

http://www.edisontechcenter.org/tesladebunked.html

Featured Image : http://geek-news.mtv.com/2013/09/26/disney-asks-the-oatmeal-to-consult-on-tomorrowland/

The Great Debate

In this post I want to talk about something which blew my mind, not solely because it taught me something I did not know before, but also for the reason that this debate (during the 1920s) had the same effect on everybody’s understanding of the universe. It is a wonderful representation of human endeavour to assess their place in the universe. Especially so because even the general public was getting involved, it’s beautiful when that happens.

I was told about this in one of my astronomy lectures, following a few short experiments conducted by Edwin Hubble and Henrietta Swan Leavitt, our view and scale of the universe exploded, almost instantly. Although I had grown up with the knowledge (now part of all textbooks) that the debate was trying to resolve, I had always taken that for granted and did not appreciate or even consider the effort that went behind cultivating that knowledge.
It also taught me about how we make observations and interpret them based on existing ideas and prejudices, it is a story of monumental insight and tragic errors.

The debate was between two astronomers, Heber Curtis and Harlow Shapley ( actual pictured below) and was about the nature of ‘spiral nebulae’ and the scale of the Universe. Heber Curtis argued that the universe is composed of many galaxies (which were known to astronomers at the time) like our own Milky way whilst Harlow Shapley argued the Milky Way was the entire universe and these spiral nebulae were just nearby gas clouds. It is quite obvious who won in the end, but I would like to go through exactly how the debate was resolved. I think it is instructive to see how scientific disagreements are resolved, by which process they are resolved.
Unknown

In 1920, Shapley was a young and ambitious astronomer. Curtis was an old pro, a “rock of clear-thinking” and a renowned skeptic. Although, Curtis was correct about the scale of the universe, his other assertions were incorrect. They both were right about some things and wrong about others.

M80_2

Messier-80 globular cluster

Shapley’s stance

Shapley had published new papers that proposed a new models for our galaxy. He had calculated the diameter of the Milky Way to be approximately 300, 000 lightyears (ten times larger than was previously thought) and placed the Sun to be 60, 000 light years away from the centre (the sun was thought to be centre of the galaxy previously).

He did this by observing globular structures, which are large collection of stars bound by gravity that orbit a galaxy as a satellite. He conjectured that these should be orbiting closer to the centre, and took into account the asymmetric distribution of these clusters in the sky and thus concluded we are not the centre of the galaxy.
Leavitt_aavso
As to how he calculated the distance, we must first talk about Cepheid variables. Cepheid variables are pulsating stars, the pulsating causes brightness changes. The relationship between the rate of pulsating and the brightness was discovered by Henrieta Swan Leavitt. This allowed Shapley to measure the distance to these globular structures, by using these cepheids as celestial candles, and estimate distances.

Once he had made these observations, he commented on the nature of these spiral nebulae, saying, for these to be separate galaxies their distances would be on the order of 100 million light years, a distance then thought to be incomprehensible and incorrect, especially when there had been limitations on estimating distances. So he believed these nebulae like the Andromeda galaxy were simply part of the Milky Way (thought to be the entire universe).
To further support these claims he used the observed instance of a nova (a cataclysmic explosion of a white dwarf) that outshone the entire nebula. To outshine Andromeda (were it a different galaxy) was, to many at the time, a seemingly impossible output of energy. So to explain that phenomenal brightness, the assertion that Andromeda and other nebulae were closer (inside the Milky Way) fit well. In retrospect, what they had observed unknowingly was a supernova.

Another astronomer, Adriaan Van Maanen, measured the angular rotation speed of these spiral nebulae (how much angular distance a certain point travelled per year), using the distance to these nebulae one can find the speed in kilometres/second. But if these nebulae were indeed galaxies, their large distances would mean the rotation speed was a significant fraction of the speed of light (which was considered to unreasonable). So he used this result to further support his argument.
To summarise Shapley’s argument, he believed the Milky Way was the entire universe, that spiral nebulae like Andromeda were inside the Milky Way and our sun was not in the centre of our galaxy. In fact he believed that nebulae were gaseous clouds.

Curtis’s stance
Screen Shot 2015-08-18 at 21.01.24
Curtis contended that Andromeda and other such nebulae were systems of stars, galaxies like our own or ‘island universes’, as referred to by Immanuel Kant. He highlighted the fact that there were more novae in Andromeda than in the Milky Way, he then asked why should there be more novae in this small section of the galaxy than anywhere else? Concluding, Andromeda being a separate galaxy explains better the density of nova occurrences.

Moreover, he did not agree that Cepheid variables were a good indicators of distance and so disagreed with the distances Shapley had worked out and thus had no problem asserting nebulae were separate entities and disagreed with the calculated distance of the sun from the centre of the galaxy and thought it to be the centre of the galaxy.
Furthermore, he disagreed with the result Van Maanen produced, arguing that the angular motion in question were unrealistically small to measure.

It became apparent later that Van Maanen’s observations were incorrect. One cannot actually meaningfully measure the Pinwheel galaxy rotate in a human lifetime.

Resolution- enter Edwin Hubble

Back in California, a 30 year old researcher at the Mount Wilson Observatory was tracking a pulsating star in Andromeda which he called “VAR!”, he measured the rate of change of brightness and thus find its intrinsic brightness. Comparing with how bright it appears he calculated the distance to be 900,000 light years, which clearly exceeded the distance of the Milky Way (and what he thought to be universe) Shapley calculated.
He continued to measure distances to various nebulae by measuring distances to Cepheid Variables and all observations pointed to the fact that these nebulae were indeed separate entities to our galaxy.

Hubble would later write Shapley a letter that presented his findings in detail.  After reading it, Shapley turned to a graduate student and delivered the remark for which he would become famous: “Here is the letter that has destroyed my universe.”

And so it was, a few key experiments redefined what was understood as the Universe. In a few key experiments, it was shown ours is not a unique and lonesome galaxy. In a few key experiments our universe grew manyfold.

It isn’t scientifically important who won or lost, both Shapley and Curtis were partially correct. Shapley was correct about the position of the sun in the Milky Way, Cepheid Variable being good standard candles, he also got a closer estimate to the galaxy than did Curtis. Curtis was undoubtedly correct in his view of the universe, and about the rotation of exterior galaxies, but he was mistaken about the sun’s location in the Milky Way and also about the size.

Shapley’s placement of our sun away from the Galactic center surely is a major accomplishment, but the discovery that distant nebulae are galaxies in their own right is one without parallel. It is for this reason that the Curtis-Shapley debate shall not be forgotten.

I guess a pretty picture of galaxies is due :

Unknown
References:

http://apod.nasa.gov/diamond_jubilee/debate20.html

http://www.smithsonianmag.com/history/how-edwin-hubble-became-the-20th-centurys-greatest-astronomer-66148381/?no-ist

Featured image : http://www.calamitiesofnature.com/archive/?c=599

End image : Hubble Ultra Deep Field https://en.wikipedia.org/wiki/Hubble_Ultra-Deep_Field

Artist Impression of Nova : http://www.space-art.co.uo

Should I study Physics? What can I do with it?

If you’ve finished year 11 or year 12 you may be in the process of deciding what to study for A-levels or what you want to study at University; and possibly angsting over the dreaded UCAS process.

If you are in anyway inclined towards studying physics or something related to it, this post is for you and I will try to convince you why you seriously should consider studying.
Physics is a brilliant subject that pull together the concepts of mathematics and philosophy to describe the fundamental nature of the world around us. It is a vast subject with numerous areas of interest, its reach extends towards stars and galaxies, right down to the fundamental building blocks like electrons and quarks.

Here is a short list of things why Physics is an awesome subject to pursue – and not just for people who want to be physicists :

  • Physics teaches you to think.
    Sure you could say that about all subjects, and I am not trying to belittle any other subjects. But Physics concern itself with the most basic concepts of life. It utilises mathematical techniques to uncover truths in an objective manner; and to do so one must develop strong analytical and problems solving skills. The point of calculus and algebra in physics can go beyond just answering questions in an exam, they cultivate a way of thinking that solve technical problems; a way of thinking that can be applied to almost all areas of life. Physics can develop skills that are highly valued by employers and it is a highly diverse set. Just look at this graph here : https://www.aip.org/statistics/data-graphics/knowledge-and-skills-regularly-used-physics-bachelor’s-employed-private
  • To put it simply, Physics explains.
    Physics provides answers to the part of us that wishes to be more aware of our place in the universe. It can explain why the sky is blue (Rayleigh Scattering), what makes the world go round (powerful love may be, but its angular momentum), what is fire (mixture of soot particles and ions that are glowing because of their temperature). It is incredibly fulfilling when you can not only admire natural phenomena but also explain why they occur, I think that alleviates the awe even further.
  • Physics is highly creative.
    Science is usually seen as a stuffy logical subject that has no place of creative and abstract thinking. That really is just false advertising in my opinion. Physics can be a highly creative subject, in fact most of my problem sets that I have to solve require new ways of thinking about a concept that I might not have even considered before. There can be unique kind of beauty in logical thinking if you do give it a chance. Experimental physicists have to be highly creative so they can design experiments to investigate whilst still maintaining low errors (so the experiment is valid). Just look at the unique ways astronomers search for exoplanets despite the challenges and limitations of equipment.
  • Physics is fun.
    You get the opportunity to do cool experiments and play with all lasers, and liquid nitrogen and all sorts of other cool toys!
  • Physics changes the world.
    If you still aren’t impressed by sheer amount of interesting stuff you get to learn, you may be a more pragmatic sort. You may think “Sure learning about why the sky is blue is fun, but how does that information help me?”. Well, without sounding too arrogant, Physics is the engine of prosperity (together with engineering). The techniques and equipments physicists develop to find stuff out has continually shaped the world for the better. Here is a list of technologies which were made possible because we gained an understanding of the underlying physics : Lasers (used in almost all cd/dvd/blu-ray players) , MRI, Cell Phones, GPS, Light Bulbs, Computers (which is a vast area in of itself), LCD/LED/Plasma televisions, transistors (try making a computer/smartphone/tablet without this. I dare you) etc. Plus as I have mentioned the vast variety of skills that you developed are greatly valued by employers and you can use those to work in the private sector and solve problems that exist the world today. Which brings us to the next question.

What can I do with Physics?
The career prospects for physics graduates can have quite a broad range of career options, and these might not be very well known. I have mentioned the skills you develop as a physicist but let me just shortlist them again for you : problem solving, critical thinking, teamwork, analysis of data, inventiveness to tackle unforeseen problems, technical writing, mechanical aptitude etc. These are valuable in a large number of jobs despite those titles not having the word ‘physics’ in them. I don’t have the time to go through a massive run down of every single career option thats open and how to achieve it, but I will again just list out various job titles physicists have gotten in the past.

  • Analyst
  • IT consultant
  • Programmer
  • Teaching/Academia
  • All sorts of engineering postions
  • Research scientist
  • R&D

Here are a few links if you want to know more, these are great resources and you can have a look around the websites themselves one you are done with the webpage. You are bound to find something that I haven’t,  all it takes is a quick google.

I did some further research and found this: ‘US survey reveals high value of physicists to industry’
It is an article that that discusses the findings of a survey conducted by Roman Czujko from the American Institute of Physics and was the head of the AIP’s Statistical Research Centre. The survey looked at 503 US-based physicists employed in the US private sector who were awarded their PhDs in 1996, 1997, 2000 or 2001. The four years were chosen so that sample on both sides of the 2000 dot-com bubble, ensuring the survey did not show a false trend.
“In nearly all cases, those with PhDs were working in areas that require the frequent use of scientific and technical knowledge, with many finding their jobs ‘intellectually stimulating and challenging’.”
They also found that 75% of the private sector physicist in 2011 reported salaries of more than $100,000 and 85% were employed in STEM fields, despite not directly involved in Physics.
“When you study physics, you learn how to deal with complexities, noise and uncertainties,” says Micheal Idelchik, “It really positions you to enter private companies and the corporate world. A degree in physics makes you very broad and very adaptable.”

Here is a link to that article: http://physicsworld.com/cws/article/news/2015/jul/03/us-survey-reveals-high-value-of-physicists-to-industry

Another update, I made a short video (around 30 seconds), hopefully it captures the essence of what I have written here and I hope you enjoy it. (The style was inspired by Minutephysics). Which I also originally submitted as an entry to the UCAS Love Learning  competition. Unfortunately I did not win, which give me the liberty to upload it on here xD

https://www.aip.org/sites/default/files/statistics/employment/careersfactsheet-p-10.pdf

https://phystec.physics.cornell.edu/content/why-study-physics

http://www.aps.org/programs/education/highschool/teachers/why-physics.cfm