What would happen if the world stopped spinning?

March 12, 2017 / The world around us / 0 Comments /

The Earth spins at roughly 1,000 miles per hour (1600km per hour), and is essential in creating the world we live in. The spinning often goes unthought about, because we are unaware of it – we have never known life without it. But what would happen if the word stopped, and stood still in space? Would we notice, survive, or even thrive? Is there a difference between a sudden stop, or a gradual one?

 

Sudden VS gradual stop

The sudden stopping of the Earths rotation is probably less likely to happen than a gradual stop (although both are extremely unlikely). However, if the Earth was to suddenly stop spinning, everything that isn’t secured down very tightly would be thrown in a Eastward direction (the direction of the Earths rotation) at about 1,000mph. The force alone of this would kill everyone and everything outright. The world as we know it would be nothing more than a pike of dust, soil and rubble. You would never even know it happened, or what how the world would change. This wouldn’t happen if the spinning gradually slowed down though.

 

Day length

The Earth takes 23 hours and 56 mins (which we round up to 24 hours) to do 1 complete rotation on its axis, which represents a day. An orbit around the Sun takes 365 days, and that makes our year. Without the 24 hour rotation of our planet, the only influence of which side of our planet is exposed to the sun is our orbit around the Sun. This means our day length would be 6 months, and our night would be 6 months. The impact on the climate would be massive – with half the world being continuously scorched, and the other plunged into darkness and cold.

 

Oceans & land

The rotation of all planets causes them to slightly bulge around the equator. Saturn for example, is about 10% wider at its equator than it is high, and this is because of the centrifugal force of its rotation. Earth is 0.3% (or about 43km) wider than it is tall. If the Earth stopped spinning the bulge around the equator would gradually disappear. The loss of this bulge would cause the oceans and seas to shift dramatically. In fact, the oceans would divide to the poles, and create one massive super continent across the equator, with 2 oceans to the North and South. Esri created an image of what this would look like:

End result if Earth stopped spinningThis would mean most of Canada, Europe and Russia would be submerged.

 

Can humans survive if the Earth stopped spinning?

No. Even if the Earth was to gradually slow down, the impact of the Earth stopping spinning on the climate would be too large. The vast majority of plants would die very quickly, either from the lack of sun and heat, or too much. As most of the life on land survives on plant life (either by eating it, or eating animals that eat it), food would become extremely rare. Much of the sea life will die out too, because most marine creatures live close to the cost. With the equatorial coasts vanishing, and the Northern/ Southern coasts deepening, the marine life would suffer dramatically. It may not all die out, but what we consider ‘food’ would almost certainly die.

Additionally.we would be exposed to sun for 6 months non-stop, followed by 6 months of complete darkness. The human body would be unable to cope with this, and disease and illness would spread rapidly. Physically, mentally, and nutritionally degraded – the human race would soon die out if the Earth stopped spinning.


Why is the sky blue?

October 8, 2016 / The world around us / 0 Comments /

A yellowy sun sends out white light which makes the black of space look blue… Confused? You should be! The blue light that you see in the sky is a result of something called light scattering (or more specifically Rayleigh scattering), caused by the particles which make up our atmosphere, and in this article I’ll explain how this works.

 

Sunlight

Sunlight contains the full spectrum of visible light. If you look at the image of the spectrum of light, you can see that blue light has a wavelength of 450nm-495nm, and at the other end of the spectrum is red light with a much longer wavelength of between 620nm and 750nm The specific wavelengths of a particle of light (or rather, a photon) determines the colour we see, but it also dictates the amount of energy that particular photon has. Particles of light with high energy will have a shorter wavelength, so blue light contains more energy than red light for example.

visible-spectrum

 

Light scattering

Light scattering is quite a complex process where a photon of light interacts with atomic structure of a molecule and induces what is called an ‘oscillating induced dipole‘, which essentially means that electrons are displaced periodically in the molecule, making one part of the molecule more negatively charged that the other. This oscillation is done at the same frequency as the light that hits it, and emits light that is identical to the light which caused this oscillating induced dipole. 

Our atmosphere is full of lots of chemicals, but by far the most abundant are oxygen and nitrogen, which combined make up about 99% of our atmosphere. Oxygen and nitrogen are pretty unique in that their molecular structure is perfect for the scattering of blue light, but not so much the other frequencies, and so blue light is scattered around much more than the other frequencies. In the crude picture below, you can see the blue light frequency causes these oscillating induced dipoles, which then emit more blue light, but red light passes right through. It is hard to picture, so I have tried to help with a diagram below.

If you are interested in the details of how this works, you can read more about it here and here.blue-light-scattering

This means that when light from the sun hits our atmosphere blue is scattered down to us on Earth, so when we look up, we see lots of blue. blue-light-being-scattered-from-the-sun-to-earth

 

Red sunsets

When the sun is very low in the sky, the sky often turns red, and this is caused by the same thing. When the sun is low in the sky, the light must pass through lots of the atmosphere to reach you, and by the time it does reach you, much of the blue light would have been scattered out, effectively filtering it out. This leaves the longer wavelength particles of light left (because nitrogen and oxygen do not interact easily with these), and so it is a dominance of these colours which reach your eyes.

 

Summary

The sky is blue because of a complex interaction with the light from the sun and the molecules oxygen and nitrogen in our atmosphere, which cause something called Rayleigh scattering. Rayleigh scattering causes blue light to scatter when it interacts with these atmospheric molecules, and this scattering of blue light over our head makes the sky look blue.

Header image courtesy of … j e r e m y…

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The sky is blue because the oxygen and nitrogen in the atmosphere scatter the blue light down, making the most abundant colour that reaches our eyes, blue. 


Do Plants Feel Pain?

March 12, 2016 / The world around us / 0 Comments /

No one wants to inflict pain on other living things, and we are all too aware that other animals like us can feel pain in the exact same way we do. They express pain in a similar way, and because they have a similar biology to us, we have a very good understanding of how they feel pain. But with plants, it isn’t so easy to understand. They lack muscles and expressions which we use to show we are in pain, and because they are so very different to animals we cannot really interpret anything as plants feeling pain. It is because of this that most people don’t even consider the possibility that plants can feel pain, and if they did, they would disregard it, but do plants really feel pain?

 

Plants & Pain

For us as animals to feel pain, our nerves transmit an impulse to our brain, which is then interpreted as pain. Plants lack this kind of nervous system, or anything that resembles it as far as we know. In addition to this, pain is often accompanied by an emotional response, and by definition, pain is a combination of physical damage and emotional distress. Plants lack the capacity to to feel anything like emotion, and there is no debating this. To feel emotion, you need something like a brain, which is pretty easy to find. The brain is important, often pretty big in relation to the organism, and lots of things in the organism lead to it. In general, a brain is pretty easy to find, and in humans, lots of blood, nerves and a big boney skull give it away.

So we can safely say that plants don’t feel pain in a conventional way.

If you think of ‘pain’ meaning a response or reaction to damage, then plants may not feel pain, but perhaps they can recognise it. Many plants have evolved to produce toxins and increase healing in response to damage. But they don’t feel anything, because to feel, you need a nervous system. Besides, this argument that plants respond to damage and so can feel pain is flawed, because their response is much closer related to our immune response (inflammation etc) than our pain response, which is largely emotional.

You may hear of studies that have shown that cucumbers ‘scream’ when cut, and so plants must feel pain, but these are absurd. Firstly, screaming requires vocal chords, something that cucumbers don’t have, and secondly, screaming is again an emotional response to pain, and plants lack the nervous system required for an emotional response. These ‘screams’ are actually gasses released when plants are cut, and are simply part of the chemical response to damage, not pain.

 

Why don’t plants feel pain?

To you and me, pain is a useful tool (despite it not being very nice). It indicates damage and allows us to respond accordingly. If you put your hand on a hot stove by accident for example, you feel pain, and so know you need to remove your hand from the stove quickly. However, plants have no need for pain, and a nervous system would never have evolved in such a thing as a plant. They are rooted in the ground and lack muscles, so they can’t respond in the same way to damage. If an insect takes a bite out of a plant, it can’t swat the insect away, but it can release nasty or toxic chemicals to get rid of the insect.

 

Summary

Plants cannot in any way feel pain because they lack the nervous system to facilitate such an emotion and understanding of damage. They do have their own ways of dealing with damage, which suites them just fine. Rather than feeling pain, plants will release chemicals to deter herbivores, and heal themselves. This release of chemicals is not in a scream of pain, but simply a reaction to damage.

Image courtesy of Doug Bowman

This Youtube video will give an overview of the information found on the article tab. If you want to know more about the topic, or want to see where the information came from, have a read of the article after you watch the video.

No, plants do not feel pain because they lack the complex nervous system required to feel pain and emotions. They do respond to damage in a similar way our immune system does though.


Why Do Leaves Change Colour in Autumn?

November 15, 2015 / The world around us / 0 Comments /
Why do leaves do red or yellow in autumn header image

Leaves in most trees contain some common chemicals:

1) Chlorophyll, which we know to be the only truly green pigment in nature,is extremely abundant in leaves and makes them green. Chlorophyll is the molecule which is responsible for converting light into usable energy in the tree.

2) Carotene, which is an orangy yellow colour. You will be most familiar with beta-carotene, which is responsible for the colour of carrots. Carotene acts as a supporting molecule for chlorophyll, and helps to absorb light frequencies that chlorophyll cannot and chemically stabilize the structures in the leaf (because being exposed to so much light can cause a rather reactive environment). Carotene will usually be found in a 1:3 ratio with chlorophyll, and because chlorophyll is so much more abundant than carotene, we only see the colour of chlorophyll. However, these carotene chemicals will still influence the colour of the leaf, and the darker a leaf is indicated a higher concentration of carotene.

3) Anthocyanins, the colours of which vary from vibrant reds to purples. The role of these chemicals is less clear, and it doesn’t have a role in photosynthesis. We do know that it is often produced in times of stress for a plant, so these chemicals could be produced in the leaves to protect from light damage (very likely, considering the nature of leaves). We also know that these anthocyanins are strong antioxidants, so their role in protecting the leaf seems quite likely.

Already, you have probably noticed these colours are all quite prominent in Autumn (or as our friends across the Atlantic Ocean call it, ‘Fall’), so now I’ll explain why leaves change into these colours before they fall.

 

Green leaves

Leaves start green, because they are extremely abundant in the green pigment chlorophyll. However, this molecule is extremely unstable, and although leaves contain carotenes and anthocyanins to help protect it, it still breaks down very quickly, and trees are constantly producing it. When the temperature drops, and day length (and so amount of light) shortens, trees stop producing more chlorophyll, and so the chlorophyll left in the leaves breaks down, and doesn’t get replaced. When the chlorophyll breaks down, it loses its green colour, and other colours of the leaves become visible.

 

Red leaves

At this point leaves of many trees become a beautiful and vibrant colour. A layer of cells stops sugars and sap leaving the leaves, and this causes the sugars to react with the sap to produce bright red anthocyanins. As I’ve said, the purpose for this isn’t very well understood, but it could be to protect the leaf and prevent and damage being made to the tree before the leaf is severed from the branch.

 

Yellow leaves

Not all trees turn red, many, such as an Oak tree will go straight from green to yellow. Leaves turn yellow because other pigments, such as chlorophyll and anthocyanins have all degraded and only carotene is left.

 

Brown leaves

You could argue the last colour a leaf turns is brown. They turn brown because all the chemicals they contained are in different states of degradation, either by light or microbes, and so there is a large variety of different compounds in the leaf. This makes the overall colour brown. You can think of it a bit like what would happen if you mixed every colour together – you get brown.

 

Perfect Autumn conditions

A number of factors affect how bright and how quickly these colours are displayed. A perfect Autumn, in my opinion, would be one where all the leaves turned a bright red all at once. For this to happen you would need very cold temperatures (which will destroy the chlorophyll quicker, and possibly stimulate more anthocyanin production) and very bright autumn days, because anthocyanin production needs light.

 

Image courtesy of Stanley Zimny

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Leaves contain a number of chemicals, which have differnet colours. The most abundant is chlorophyll, which is green. However, chlorophyll is easily broken down by low temperatures. The other chemicals are more resistant, and these are anthocyanins (which are red) and carotenes which are yellow.


What Makes up Everything?

October 14, 2015 / Humans, The world around us / 0 Comments /
Header image of a black board with chalk calculations

Start with a human

Lets start with a very complex organism – say, a human. Humans are made up of a number of organ, like the brain, heart and liver. Organs are usually self-contained, and have a specific function in the body, for example, the liver is there to filter out toxins and neutralizes toxins. These organs are quite big in the scheme of things, and if you hold out your two fists together that is the size of your heart. These organs are made up of tissues, which are an organisation of similar specialised cells that perform a specific task, and a typical example of a tissue is muscle. Cells in muscles are specifically designed to produce force which help us to move.

 

Microscopic

Tissues are the smallest thing we can see with our eyes, and these tissues are made up of individual cells, which can only been seen under a microscope. A skin cell is approximately 30 micrometers (30µm) in size, and this means that you can fit just over 30 skin cells in 1mm. These cells are then made up of tiny structures called organelles, which fulfil a similar role to the cell as organs do to our body. Organelles have specialised functions which include creating proteins, protecting DNA and creating energy. All cells are very similar in this composition, even plant cells to some extent (but there are some key differences too). All of these organelles are made up of molecules, and the size of these molecules can vary quite dramatically. The most commonly known molecule is DNA, which if stretched out, would form a very thin thread of about 2 meters. In contrast, a glucose molecule is about 1.5µm (20 times smaller than a skin cell). You will struggle to see some of these smaller molecules with a microscope.

 

Atomic

All molecules are made up of atoms in various compositions. . Glucose for example, contains six carbon atoms, twelve hydrogen atoms and 6 oxygen atoms, and water contains hydrogen and oxygen. Hydrogen is the smallest of all atoms, and is only 53pm wide, which is 0.0000000053cm. Hydrogen atoms are so small you can only just see them under an electron microscope

 

Subatomic

These particles have never been seen, but we know they are there through experimentation.

All atoms, no matter the size, are made up of 3 particles. Neutrons, protons and electrons. Neutrons ( which have no charge) and protons (which have a positive charge), make up the nucleus of atoms, which gives it an overall positive charge. Electrons have a negative charge and ‘whiz’ around the nucleus in a hazy cloud. An oxygen atom will have 8 protons, 8 neutrons and 8 electrons. For a long time people believed that these particles were the smallest unit which makes up the universe, but then quarks were discovered.

Quarks

Quarks make up the protons and neutrons, and there are 8 types of quarks:

  • Top Quark
  • Up Quark
  • Down Quark
  • Bottom Quark
  • Strange Quark
  • Charmed Quark

Yes – these names are real.

Quarks have partial charges, for example, an up quark has a charge of +2/3, and a down quark has a charge of -1/3. A proton is made of 2 up quarks and 1 down quark, which is what gives it a total charge of +1 (2/3+2/3-1/3 = 1).

Quarks are widely accepted to be the ‘fundamental particles’, and that there is no smaller particle which makes them. In fact quarks cannot exist on their own, and can only exist when they form neutrons and electrons, so deciding if they truly exist is up for debate.

 

What makes up Quarks?

It is a bit of a brain twister. Our minds are wired to think there is always a smaller unit because this is how the world around us works, but this logic doesn’t play well in particle physics. There may well be something smaller than a quark which makes up quarks – but it isn’t thought to be likely. Quarks possibly only exist because they have energy, and so you could argue that energy makes up everything.

 

Summary

Everything, including you, me the screen you are reading this on and the grass outside is made up of a combination of tiny fundamental particles called quarks. Alternatively, you could argue that these quarks may only exist because they have energy, and so everything is made up of energy.

Or, you could argue that everything is made up of space, because there is a large gap between the atoms nucleus and the surrounding electrons, which by volumes, takes up much more space than the actual particles in the atom, so we are mostly just space.

This Youtube video will give an overview of the information found on the article tab. If you want to know more about the topic, or want to see where the information came from, have a read of the article after you watch the video.

The most fundamental particle is called a quark. Nothing makes up a quark (that we know off), but it is thought that energy may make up quarks, in which case, energy makes up everything.


Why Does Metal Cause Lightning in the Microwave?

September 29, 2015 / The world around us / 0 Comments /
Why does metal cause lightening in the microwave?

Everyone knows that when you put something metal in the microwave it can cause a lightning storm. Most people will assume that this is something to do with the fact that metal conducts electricity, but will leave it at that. So in this article I will explain just what is going on.

 

Microwaves & Metal

Microwaves cannot penetrate metal in the same way they can penetrate food, ceramic bowls or plastic. Instead they reflect off the surface, but when they make contact with the metal they induce an electromagnetic field in the surface of the metal which causes electrons to move, and it’s the ability for electrons to move so freely which makes them such good conductors. These electrons will accumulate and concentrate in bends and points of the metal – the tighter the bend/ sharper the point the more tightly electrons will accumulate. It is this grouping which will cause the lightning spark, so things with very tight bends, such as forks, or sharp points like scrunched up foil will be much more reactive than a metal bowl.

 

Air ionisation

Electrons have a negative charge, and so the accumulation of electrons in an area like this will create a strongly negatively charged area. This strong negative charge will repel electrons in nearby air molecules and strip them from the atoms. This creates what is called plasma, and the electrons in the air are able to flow freely, much like they do in the metal, and allow a current to flow. This creates a positively charged area of air, and a negatively charged bit of metal which is perfect conditions for a current to flow. Electrons from the metal will flow up to the positive atoms in the air creating a current which releases energy that we perceive as little bolts of lightening/ explosions, and sometimes ‘popping/ banging’ sounds.

It is possible that the stripping of electrons can continue through the air until an object is met (probably the wall of the microwave oven) and then the lightning will arc between the two through the plasma rather than just spiking out into the air.

This is very similar to what happens in lightning storms. In these storms clouds become negatively charged (from winds and varying temperatures). This negative charge attracts positive charges from the ground (and repels negative charges) until the positive charge of the ground and the negative charge of the clouds becomes so strong the air becomes ionised, which allows the negative charge to create a current to the ground. This current releases energy that we see as lightning, and hear as thunder. Slow motion lightning strike is similar to what happens to metal in a microwave

If you look at the impressive animation on the right from scijinks of a slow motion lightning strike, you can see the air ionising to connect the positive ground and the negative clouds. Once a connection is made, then the lightening will strike, discharging the current. A similar mechanism occurs in the microwave.

Summary

So metal causes a small lightning storm in a microwave for the same reason that it can conduct electricity – free electrons. Microwaves cause these electrons to accumulate in tight points of the metal, which means forces the electrons off the molecules in the air. This creates what is called ‘plasma’, which means electrons are free in the air, much like they are in metal. With electrons being free like this, they can create a current and discharge the imbalance of charges that the concentrations of electrons causes. This discharge is what we see as lightning.

Image courtesy of Garrett Coakley

This Youtube video will give an overview of the information found on the article tab. If you want to know more about the topic, or want to see where the information came from, have a read of the article after you watch the video.

Microwaves induce an electromagnetic current in metal objects, which causes electrons to accumulate in points and corners. This causes large positively charged areas to build up against large negatively charged areas, and eventually, the electrons will ‘discharge’ and cause lightening as they rush towards the positivly charged area.


Why is the Sea Salty?

September 16, 2015 / The world around us / 0 Comments /
Why is the sea salty

Although fresh water runs into the sea, the sea is salty. Its strange really, and so in this article I’ll explain why the sea is salty.

 

Minerals in the Earth’s crust

The ground is not just inert dirt and rocks – it contains an abundance of chemicals and minerals. Amongst all these minerals is sodium, which is the the 6th most abundant mineral found in the crust. Sodium is most commonly found bonded to less abundant (but still relatively plentiful) chlorine, which forms sodium chloride – what we call table salt. Salt is water soluble, and so when it rains, the salt in the ground dissolves in the rain water and runs into the rivers, and ultimately into the seas.

When the water in the sea heats up from the sun it evaporates and forms clouds, but the salt is far to heavy to evaporate with the water, and so stays in the seas.

This process continues over many many years, and the weather/ rain will break rocks up/ wear rocks down, which exposes more mineral rich rocks/ soil, which rain water will also dissolve and wash into the sea.

This process concentrates salts and other minerals in the sea, because the salt cannot escape, but the water can through evaporate. Gradually this builds up the salinity of the seas to the point where the seas are significantly saltier than water in the rivers which feeds them.

 

Other causes

When underwater volcanoes erupt they release a number of chemicals into the seas and oceans which were previously trapped in the crust below the ocean floor. Amongst these chemicals will be sodium chloride (salt), which will further contribute to the salinity of the sea, but to a much lesser extent than the rivers do.

 

What about other minerals

With sodium only being the 6th most abundant mineral in the crust, and chlorine being even less abundant, you might wonder why the sea is salty and not another kind of flavour (minerally?). Indeed aluminium, calcium and iron are far more abundant that chlorine and sodium, so you might expect the sea to be more abundant in these minerals than sodium and chlorine.

Iron  – Iron is nearly 5% of the crust, which makes it almost twice as abundant as sodium, and it is in fact the most abundant element on the planet. Very little iron reaches the sea e sea because when water comes into contact with iron it readily forms a compound called iron oxide (which we know as rust). Iron oxides are not soluble, and so don’t easily run off into the seaA graph showing the relative abundance of minerals in sea water

Aluminium – Aluminium is nearly three times as abundant as sodium is, but very little is found in the sea for the same reason as iron. Aluminium reacts with oxygen far too quickly, and becomes insoluble too.

Calcium – Calcium is usually found in the crust in the form of calcium carbonate, which is very stable and so doesn’t dissolve very well in the rain water. Calcium compounds do dissolve in water to some extent though and do make it to the sea, which makes calcium one of the more abundant minerals in the sea.

Other minerals are present in the water, the most notable of which is potassium and magnesium, which are moderately abundant in the crust, but due to solubility, are found in higher concentrations in the sea.

Interestingly, it is the presence of these additional minerals which makes using sea salt to season food a healthier option than regular table salt.

 

Summary

The sea is salty because rain water continuously washes salt from the rocks/ soil on land into the sea. The salt cannot escape because the salt atoms are too heavy to evaporate with the water the dissolved in.

Despite not being the most abundant minerals in the sea both sodium and chloride ions are water soluble, and so will readily wash into the sea where other more abundant elements won’t. This is why sodium and chloride concentrations are higher in the sea than in the crust.

Image courtesy of ninfaj

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Over millions of years salt from the land has been dissolved and washed into the sea by rain water. As salt it heavy, it cannot evaporate, and so stary in the sea.


When Will the World End?

August 21, 2015 / The world around us / 0 Comments /
When will the world end

In order for the world to end, there truly would need to be a catastrophic global event. Something along the lines of a meteor collision, our Sun collapsing or even a nearby galaxy crashing into ours. These are all things that could very easily happen at some points in the planets life, but what will happen first? What will cause the Earth as we know it to be destroyed? In this article I’ll look at the most possible causes for the end of the world, and determine the likelihood of them happening.

 

Polar shift

The polar shifts is something that is actually occurring right now, but it can take thousands of years to complete. During the polar shift the magnetic field of the Earth becomes much weaker. The magnetic field protects us from harmful solar flares, and when the magnetic field weakens, we will be much more vulnerable to these flares. Some people believe that this could have some extreme effects on our planet, and maybe destroy it. For starters, it could seriously affect some animals who use the poles to navigate, and this could impact ecosystems to an extent which is hard to predict. It would also expose us to higher amounts of solar radiation, which will have an unknown impact on us.

However, the last polar shift was some 780,000 years ago, and during this time humans were not only surviving on Earth, but thriving, and expanding. It was around this time that early humans were reaching Britain, and this suggests that the last polar shift wasn’t particularly extreme or devastating.The magnetic field of the Earth protects the planet from solar flares.

There a chance that during the last polar shift the sun was going through a calm spot, and no serious solar flares were sent our way, and we might not be so lucky this time. A particularly nasty solar flare could possibly have a serious impact on our planet, however, the chances of it destroying Earth is pretty slim.

So although there is a chance the polar shifts could bring an end to our world, it is very very unlikely. Chances are it will just cause some disruption, which is lucky really, because it is happening now!

 

Global warming

The next event which could end the world as we know it global warming (despite some people still denying it).

The full affect of global warming on our planet is unknown, and is still largely in the hands of the world leaders. However, we do know that it will affect some vital parts of our planet, which are essential for our survival. Crops will be most heavily affected, some will benefit, whereas others will fail. Some parts of the world will be more productive, whereas other will lose the ability to grow food. The overall net global productionunusual or extreme weather reduces crop yield. of food isn’t known, but it can easily cause instability around the globe. You can see from the graph (from the EPA website) to the right that drought (which will be more common in mid America) and other extreme or unusual weather events consistently cause a decreased yield in crop production.

Growing populations, lower food production, fewer resources and more extreme weather is a great recipe for global disaster. Could it cause a devastating global war – quite possibly. Will it cause the world to end? – unlikely. It will cause problems for the future, sure, and may even cause the human population to decrease, but that is probably the extent of it. Global warming will probably have a greater impact on our planet than the polar shifts, but it is unlikely to cause the world to end.

 

Asteroid impact

There is always the chance the a massive asteroid could crash into the Earth at any moment and destroy the planet completely, or at least cause enough damage to wipe out the human race. After all, it happened to the dinosaurs, so it could happen to us. Asteroids are a very real threat, and so NASA is trying to identify all the objects in space which could cause a world ending event.

NASA has identified a number of asteroids which could impact the Earth, but thankfully, the odds of a collision are pretty low. The greatest identified risk has a 0.29% chance of impacting Earth in the next 100-200 years, and this asteroid isn’t thought to be enough to end the world, just cause some damage. You can view all the identified objects and their risk of impact here, all of the odds of an impact are very low. However, not all the asteroids out there have been identified, and there could possibly be an asteroid hurtling towards Earth right now! The odds are very very low though.

So although an asteroid hitting Earth would cause much more damage than the polar shifts or global warming, it is unlikely to be the cause for the end of the world simply because the odds of it happening are too low.

 

Galaxy collision

The above threats seem to be the only real threats to Earth for the next 3-4 billion years. The poles will shift a number of times during this time and if we survive through global warming, we would have survived through the worst of it. Earth will probably have probably been hit by a couple of asteroids too, but it’s still unlikely to be anything too devastating (there is that small chance though, and 4 billions years is a long time).

According to Dave Goldberg, a Physics Professor at Drexel University, in about 4 billion years the nearby galaxy Andromeda will collide with our home galaxy – the Milky Way. This collision will take a few billion years to complete, but the galactic disruption is sure to cause some devastating effects on our galaxy. Planets, asteroids and even stars will pass through our own galaxy, some collisions are certain, and this can release massive amounts of radiation. You can view the below video to see what the collision of the 2 galaxies will look like.

 

Gravitational forces in our galaxy will shift dramatically, and a passing star could easily pull us out of orbit and fling us into the freezing depths of space. Yet there is still a chance Earth will survive. Fortunately space is indeed made up of a lot of space, and there is a chance that our solar system will pass through some of this ‘space’ in the Andromeda galaxy, and we would survive!

The collisions of these galaxies won’t be a quiet event, and our world could end in any number of ways, all of which are far beyond our control, but there is still that chance we can survive.

 

Death of the Sun

The death of the Sun will surely be the end of the world. Not because we would no longer get light and warmth, but because the sun will expand and incinerate our planet; and possibly even engulf it. Estimates on when this will happen are not so clear, but it will probably happen between 5-7 billion years from now. Being engulfed by a star will truly spell the end of our planet, but the world as we know it will end many years before this, due to the heat from the Sun. Everything on our planet will be burnt to a crisp, and Earth will more closly resemble Mercury (the closest planet to the Sun at the moment) that what we know Earth as today.

Unlike all the other threats, there is no chance for the Earth escaping being incinerated and engulfed by our Sun.

 

Summary – When will the world end

Polar shifts and global warming pose a slight risk to our planet, but they are more likely to disrupt our planet’s ecosystem and climate than destroy the it. Asteroids pose a very real risk, but the chances of a collision from an asteroid big enough to destroy it is extremely low (but that chance will always exist). So there isn’t anything in the foreseeable future (few thousands of years) which is likely to cause the end of the world.

However, in about 4 billion years time, this will all change. Our galaxy will collide with another, which will throw radiation, asteroids, planets and stars at us, and this could indeed cause the end of the world. If we somehow survive this collision the Earth will soon be burnt to a crisp by our own Sun, and engulfed – completely destroying the planet. So the world will definitely end in 4-5 billion years, but there is a slight risk it could end sooner.

Image courtesy of Royce Bair

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There are a number of events which have a small chance of causing the world to end sooner, but the most definate answer is in about 4-5 billions years, when our sun expands and bruns/ engulfs our planet.


Do Dock Leaves Help Nettle Stings?

August 14, 2015 / The world around us / 2 Comments /
Do dock leaves help cure nettle stings

Every kid at some point got stung by a nettle at least once. It was many times in my childhood, but without fail whenever it happened someone, be it an adult or friend, would tell me to quickly find a dock leaf, and rub it on the sting. I would always comply without question, as I’m sure any child would do, and quickly go off looking for a dock leaf to vigorously rub on the sting. I think it did kind of help…maybe, but the sting never went away properly, and would itch later. I always put this down to not getting the dock leaf fast enough, or the fact that the dock leaf disintegrated whilst rubbing, so I didn’t get a full dosage of the antidote, but now I’m not so sure. So here I’ve looked at the science of dock leaves and nettles, to see if dock leaves help nettle stings, as they are claimed to.

 

What makes nettles sting

The leaves of stinging nettles contain lots of little hairs, which act as a toxin delivery system to anyone who brushes up against them too vigorously. Different nettles from different parts of the world seem to contain different chemicals which cause the sting. For example, Urtica thunbergiana a species of nettle native to Japan contains oxalic acid and tartaric acid, whereas the needles in Urtica dioica, the species which is native to Europe and North America, contains formic acid, histamine, serotonin and acetylcholine. Seeing as I am from Europe, and not writing in Japanese, I’ll look into the European nettles and their chemicals.

Formic acid – Obviously an acid, and one which can pack a punch. This acid is found throughout nature and stinging ants use formic acid in their venom too. Like all acids, it hurts to have it on your skin. You would expect dock leaves to contain something that can neutralise this acid if they can combat a nettle sting.

Histamine – This is a chemical which we naturally produce and use to regulate the inflammatory response of our immune system – the more histamine in an area, the more inflamed it will become. It is because of histamine that nettle stings go red and itchy (although I’m sure the formic acid also triggers an inflammatory response too). Histamine is found throughout nature, and its high content in strawberries is the reason babies cannot eat them! You would expect dock leaves to hopefully contain an antihistamine which will counteract histamine. Histamine itself doesn’t seem to cause pain, but it can cause that persistant itchy sensation that nettle stings can give you.

Serotonin – Serotonin is a neurotransmitter which we naturally produce, and although commonly associated with mood, serotonin does act as an irritant when injected.

Acetylcholine – This is another chemical we commonly produce in our own body, and the most interesting to be found in a nettle sting. Acetylcholine is a very important neurotransmitter, with a number of roles in the body. Oddly, acetylcholine seems to possess pain relieving properties rather than irritating properties. When injected into rats (to try and identify what caused pain from a nettle sting), acetylcholine didn’t cause any harm. As there is nothing to suggest that acetylcholine actually causes pain, I won’t look into how dock leaves can inhibit it.

So, the main culprits in a nettle sting are formic acid, histamine and serotonin.

 

The dock leafDock leaves cannot neutralise any chemicals from a nettle sting.

Dock leaves pose little interest to botanists and attract very little research from anyone. The reason for attracting little attention is that they are pretty average for a plant and don’t contain any interesting phytonutrients. So, although there isn’t anything specific about dock leaves, we can make assumptions on what is in a dock leaf based on typical plant compositions.

For starters, plant sap has a pH of 6.4, which is very close to a neutral pH, and actually very slightly acidic. Although it isn’t as acidic as formic acid, a pH of 6.4 is unlikely to be able to neutralise the formic acid from the nettle sting significantly.

Next we will look at histamine, to counter the effects of histamine, a dock leaf should contain an antihistamine chemical, or at least an anti-inflammatory. Anti-inflammatories are found in some specialised plants, the most famous being turmeric, which is the only source of the anti-inflammatory curcumin. Dock leaves are very unlikely to be contain any anti-inflammatories though. The only plants which contain anti-inflammatories are herbs, and dock leaves are not related to herbs. So dock leaves probably can’t stop the inflammation and itching caused by stinging nettles.

Dock leaves are also unlikely to be able to inhibit the action of serotonin either. Plants containing anything that can inhibit serotonin are even rarer than ones which contain anti-inflammatories, and again, they are usually herbs.

Finally, we have already ascertained that the acetylcholine found nettle sting probably doesn’t cause pain. Even if it did, dock leaves won’t contain anything that can inhibit its action.

 

What about the rubbing??

The act of rubbing nettle stings can actually stimulate certain nerves, which can reduce pain. This has nothing to do with the dock leaf, but the act of rubbing the dock leaf (or any leaf) can help reduce the pain from stings.

 

Summary

There is nothing in a dock leaf which can neutralise or counteract the pain and inflammation from a nettle sting. As plants go, dock leaves are unimpressive. However, the act of rubbing a dock leaf on a nettle sting can help reduce the pain. It is the rubbing which reduces the pain though, not the dock leaf.

So next time you, or someone you are with gets stung by a nettle, just rub the sting with your finger, it has the same effect as a dock leaf, except your finger won’t disintegrate and turn the sting green with sap.

Images courtesy of J Brew and Rhian

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Yes. Although there is nothing in a dock leaf which can neutralise the nettle sting, the act of rubbing a sting can reduce the pain. There is no need for the dock leaf though.


Why Do Helium Balloons Deflate so Quickly?

August 10, 2015 / The world around us / 2 Comments /
Header image for article 'why do balloons beflate so quickly'

Helium balloons consistently deflate faster than balloons filled with air, which is odd, and often frustrating. You would think there is more importance in making a more secure seal for the helium balloon than the regular balloon to prevent any helium escaping, because it is lighter than air. Also, helium balloons are a bit more special (and expensive) than regular air balloons – so you would like to think there was a bit more care in their creation, and that they would last longer, but they don’t. Heluim balloons always go down, but it’s not a case of being ripped of with a cheap balloon.

 

Atomic size

A helium balloon, will contain pretty much 100% helium (surprisingly) and helium is a very small atomIn fact, helium is the 2nd smallest atom on the periodic table. In addition to this helium is found in a monoatomic form in gas, which means it isn’t bonded to anything, which means it can move much more freely.

Air balloons on the other hand, are made up of 78% nitrogen gas (which is diatomic (N2)), and 21% oxygen (also diatomic) alongside small amounts of other molecules including carbon dioxide, argon and water vapour – all of which are also quite big molecules. These molecules are all made up of large atoms, and can diatomic, or even triatomic in the case of carbon dioxide and water, which makes them very large indeed, much much larger than helium.

Helium is the 2nd smallest atom on the periodic table.

As nitrogen and oxygen are by far the most abundant molecules in air, I’ll compare the size of these to helium. From looking at the above periodic table you can see that oxygen has an atomic number of 8, whereas helium is 2. This gives oxygen an atomic mass of 16, and helium 4. As oxygen is diatomic (2 molecules) in its gas form, the mass of the oxygen in the air balloon is 32, whereas the mass of helium in the helium balloon is still 4.

So, in short, the oxygen in the air balloon is 8 times bigger than helium, and this means that helium can diffuse through the balloon wall much easier than oxygen. Nitrogen is right next to oxygen on the periodic table, and so is a similar size to oxygen, and will find diffusing through the balloon wall just as difficult.

 

Balloon material

The material of the balloon is key to allowing this diffusion to happen. Most balloons are made up of an elastic polymer, which a mess of long strands all tangled together. This allows the balloon to have elastic properties, but also allows the helium to escape. These polymers will pack together very similar to a pile of spaghetti. Although it’s quite dense, there is are small holes, and small molecules like helium can easily slip through them. If you imagine the balloon wall to be a pile of spaghetti, then sprinkling peas on it would be like helium gas coming into contact with it – some would easily fall through the spaghetti. Nitrogen and oxygen will be more like meatballs, which would make contact with the spaghetti at multiple points, and struggle to pass through any gaps.

 

Summary

No matter how tight you tie the end of a balloon, helium balloons will always deflate faster than regular air balloons. This is because the helium atoms are many times smaller than the oxygen and nitrogen molecules which inflate air balloons, and so are able to diffuse through the holes in the balloons skin much easier. This mean more gas can escape the helium balloon than the air balloon in any given time.

 

Image courtesy of Heartlover1717

This Youtube video will give an overview of the information found on the article tab. If you want to know more about the topic, or want to see where the information came from, have a read of the article after you watch the video.

The helium molecules are so small, they can pass through the balloon wall – causing it to deflate.