Why is the universe expanding?

Why is the universe expanding?

photo of supernova in galaxy
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Is the universe expanding?

First, it’s probably a good idea to wrap your head around the idea that the universe is expanding and how this is even possible. We know that the Big Bank resulted in a (very rapid) expansion of a plasma of pure energy. Later, once it cooled, it started to coalesce and form basic atoms of matter, such as hydrogen. The key point is that even though matter as we know it (which comprises less than 5% of the universe) started to form, the universe did not stop expanding. And if the universe is expanding that means that everything in it is expanding – including matter (not just the ‘in-between stuff’ we refer to as dark matter and dark energy). Think of a balloon. Blow it up a little bit. Then write something on the balloon with a thick marker pen. Then blow it up some more. You will see the text (atoms) breaking up and expanding together with the the rest of the balloon (the universe). This raises questions on a sub-atomic level of how the four forces (gravity, electromagnetism, weak and strong nuclear forces) are able to respond to keep matter (as we observe it) intact. Or is it all just relative since we’re all expanding at the same rate (enter Mr Einstein!)?

How do we know the universe is expanding?

We now know from calculations such as the ‘Hubble constant’, that is based on the the observation of a cosmic microwave background¬†(a faint glow emitted from the very early part of the universe after the Big Bang which we are able to see using the European Space Agency’s Planck telescope), that the universe is expanding. Mathematical calculations based on the observations of this period in the early life of the universe are used to predict what this constant (i.e. the speed of expansion) is today. This, combined with measuring distances between stars and other methods gives us a basis to substantiate the idea that the universe is expanding and at what rate.

The mystery of dark energy

That’s the easy part. The hard part is getting to grips with strange cosmic phenomena such as dark matter and dark energy. The latter seems to have the opposite effect of gravity so that rather than stars and planets following Newton’s Law of Gravitation (later expanded/redefined by Einstein) that holds that large objects (this theory doesn’t work as well on the sub-atomic level!) will attract each other based on their mass (the larger the mass the bigger the gravitational pull), dark energy has the effect of pulling them apart. Given the prevalence of dark energy in the universe it seems that this tug-of-war between gravity and dark energy (dark energy is winning) goes some way to explain why the universe is expanding.

Why this expansion is accelerating and what precisely dark energy’s role in this is remains unclear.

For now.

Einstein vs Newton! How time is relative and why it matters

Einstein vs Newton! How time is relative and why it matters

If you’re even remotely into physics or science generally (or you’ve just been alive during the last 100 years) you will have heard about Einstein’s theory of relativity. To properly understand it though, and it’s importance to our understanding of how the universe works, is another matter entirely.

The truth is that, while complicated, it’s also absolutely fascinating!

Another famous scientist (who lived long before Einstein) was British scientist, Isaac Newton. Newton did away with the accepted theory of the time that the natural state of any object anywhere in the universe was stationery. Instead, he proved that all objects are in a constant state of movement and that the movement of each object is relative to the movement of other objects (both men also went on to develop theories about gravity too but that will be the next post).

Interestingly, while Newton touched upon the theory of relativity before Einstein, it was the latter who found a hole in Newton’s research when he realised that the concept of ‘time’ was in fact a relative construct (this is where most people log off but stay with me).

Assuming, as Einstein did, that the speed of light is constant (186,000 miles per second) it doesn’t matter how fast another object is moving – the speed of light is not relative, it remains the same. Always.

Now, if the speed of light is constant, that meant that Newton’s theory that everything moved relative to everything else was flawed (read ‘imperfect’).

For example, if you were to flash a light, two people travelling at different speeds – one walking straight toward the source of the flash and another running in the opposite direction, the person facing the light will observe the flash (what astrophysicists would call an ‘event’) before the second person because time is equal to the distance something has travelled divided by its speed. The speed with which the light rays were travelling were the same for both persons, but as the distance is different their observation of the flash would have occurred at different times.

In other words, the time of the flash is different (or relative) for each of the two individuals observing. That, ladies and gentlemen, is relativity!

Why salt kills. And not because you eat too much of it!

Why salt kills. And not because you eat too much of it!

Most people would probably vote sharks as their number one fear when thinking about swimming in the sea.

Here’s the thing though. The amount of shark attacks on humans per year globally is a tiny fraction compared to the number of people who drown because they get swept up in a strong current.

Most of us have experienced the joy of swimming in the sea and being flung around by incoming waves. That’s part of the fun. But it can also be dangerous.

While the wind accounts for most of the waves on the surface of the ocean, other things, such as the gravitational pull of the moon, the density of different sections of water mixing together and the salinity (salt content) of the water all affect the under-surface currents which can be far stronger.

The main culprit, believe it or not, is salt. That’s right, that very same shiny, innocent-looking, tasty condiment we sprinkle on our food everyday.

Why? Because different bodies of water in the oceans contain different levels of salinity. When they collide, the denser water (the one with the most salt content) starts to flow under the less dense water creating a current where the water with less salt (think of a clear jug of water mixing with a jug of water with a few cups of salt) rises to the top of the mix. Now expand this to the oceanic scale and you can start to see how dangerous this can be for anyone (humans that is, some animals and fish thrive on it for feeding) trapped within this vortex trying to swim against this force.

So if you want to avoid currents, stick to the pool!

Red is hot. Blue is cold. Right? Wrong.

Red is hot. Blue is cold. Right? Wrong.

It’s always amusing to think of how much of our everyday lives, things we take for granted, are actually based on fallacies.

When you go into a bathroom and you look at the tap you will sometimes see the colours blue and red, indicating the temperature of the water depending on which tap you turn.

Of course, we don’t question this. We all know what it means. Red…think of a red hot coal on a barbecue, is hot. Blue…think of the lips of a freezing corpse in a chilly morgue, is cold. You get the image.

But the reality is that that when something is heated (and I mean really heated) it goes through several colour changes. Paradoxically, red is in fact the coldest of the colours when something is heated. The next temperature stage up from red is white and the hottest temperature colour is…you guessed it…blue.

Probably best to stick with H and C for the taps.

Source:

NASA (With appreciation and attribution to Earthsky.org)

The ocean – not the rain forest – is Earth’s lungs

The ocean – not the rain forest – is Earth’s lungs

If you were asked where the majority of oxygen in the Earth’s atmosphere comes from what would you say?

The rain forest?

Wrong.

Scientists estimate that between 50-80% of the oxygen on Earth is produced by the ocean. More specifically, it is produced by plankton and other tiny micro-plants that drift with the oceans currents and float close to the surface.

The reason being that these plants, similar to others on land, grow and survive through photosynthesis (from carbon dioxide and sunlight) and produce oxygen as a by-product.

Given the vast expanses of the ocean and the manner in which such plants can travel on currents that spread them wide across the planet’s surface they are major producers of oxygen.

That said, marine life are major consumers of oxygen (they also need it to breathe) while many also feast on plankton.

Source:

Earthsky

You think zombies exist only in movies? Think again!

You think zombies exist only in movies? Think again!

Scientists have discovered that a particular species of fungus targets carpenter ants that live in the rainforests of Thailand.

Now for the gory part.

This fungus, once it finds its way into the body of it’s host ant, multiplies to such an extent that it occupies the ant’s entire body which leads to muscle decay – although the ant is still alive. After a few days the fungus assumes control of every aspect of the ants movement and behaviour – the ant is, for lack of a scientific term, zombified.

Once the fungus is completely in control of its host, it can effectively make the ant do anything it wants. As an effect of the fungus replacing the functions of the ants own organs, the ant eventually convulses and falls from the tree onto the moist soft ground below- fertile ground for fungal breeding.

Then it gets really creepy.

For some reason, the fungus, which now controls the physical movements of the ant, manipulates the now detached muscle fibres within the ant’s head that allows the fungus to control the opening and closing of the ant’s mandibles. It then gets the ant to bite down effectively lock its jaw onto a leaf – it does this because a leaf is the perfect vehicle for the fungus to escape onto once it ultimately poisons and then breaks out of the ant’s head. It then shoots is spores onto the leaf with the purpose of infecting another passing ant, thereby multiplying.

While recorded and documented, it is still not understood within the scientific community why this final act of making the ant bite down on a leaf always happens at a particular time of day – high noon.

So there you have it. Zombies, alien mind and body control and showdowns at high noon.

So spare a thought for these poor ants next time you see an episode of the Walking Dead!

Source:

National Geographic

Why the static on your analogue TV channel was actually pretty cool

Why the static on your analogue TV channel was actually pretty cool

Ok, so I appreciate that not many of the younger generation will appreciate that analogue TV was once a thing. Trust me, digital is better.

For those of us who do remember it though, one of the things you will no doubt ‘fondly’ recall is the static or ‘snowy’ screen – what NASA refers to as the ‘in-between channel’.

It turns out that there is actually a pretty cool reason behind that static.

Around 13.8 billion years ago there was, according to most theories, a singularity that erupted in space causing a bang. A big one. This ‘Big Bang’ resulted in a massive sudden (relatively speaking) inflation of energy in the form of microwaves that, over time, charged different particles which interacted with each other resulting in the formation of galaxies and planets. The energy emitted from the Big Bang is still detectable through infrared telescopes today and is known as the cosmic microwave background.

So if you do still have an analogue TV you can tune to an ‘in-between channel’ and the static you see on your screen is, in part, the afterglow of the Big Bang.

Source:

NASA

Looking for creative inspiration?

Looking for creative inspiration?

If you don’t mind being sleep-deprived then this trick might help.

Salvador Dali, the Spanish surrealist painter, famous for paintings such as the Melting Clock and the Burning Giraffe, apparently sought inspiration for his hallucinogenic style on the intercept between dreams and reality.

Wanting to tap into the imagery of the unconscious imagination (and obviously needing to be conscious to paint the image) he would sleep holding a metal key in his hand hovering over a tin plate. When he fell asleep the key would fall from his hand and onto the plate, the noise waking him up.

At that very point (where the mind was still half asleep) he would capture the image of what he saw in his mind and incorporate that into his painting.

Alternatively, I hear Netflix is good too.

Source:

History.com

Why we don’t need welders in space

Why we don’t need welders in space

When I was a kid I was always fascinated when I watched welders at work, with their Star-Wars-like face masks and spark-spewing flame guns.

Welding is still common in the construction industry today. It remains the quickest and securest way of binding two metals together to form a seamless single unit. It’s used on everything from shipping, to building airplanes to car manufacturing and much more.

However, if you took a welding gun to the moon and tried to weld two bits of metal together you would struggle. This is because of the lack of oxygen which is a fundamental component in producing the flame. We can call this hot (or normal) welding.

It just so happens that there is another way in which metals can be bound together which do not require melting them beyond their melting point. It’s called cold welding.

How does it work? Well, in the vacuum and cold temperatures of outer space, if two pure pieces of metal made up of the same or similar elements were to collide, they would stick together. This is because the sub-atomic particles that make up both bits of metal literally jump across from one piece of metal to the other when they come into contact because the atoms (and the electrons and neutrons that make up those atoms and interact with each other) do not recognise the other piece of metal as being separate. So when they touch, the contact forms a pathway through which atoms from both separate pieces flow into each other and form a solid single piece of metal. Sort of like pouring two separate cups of water into the same bowl. Once they’re mixed, there is no telling which part of the final bowl of water came from which cup.

Why does this not happen with metal here on earth? Because the atoms from each separate piece of metal are in constant contact with atoms in the earth’s atmosphere which produce chemical reactions (such as oxidation) and this forms a barrier between the two pure metals. As a result, their atoms will not automatically bind with similar atoms of the other piece. In effect, other particles get in the way.

To avoid metals automatically fusing together in Space, astronauts are now equipped with metal tools that have a durable outer protective layer (such as ceramic) and are also advised not to bring into contact (outside of the space craft) metals that are of similar compositions to reduce the risk of cold welding.

Source:

Mentalfloss

8% of men across parts of Asia (and 0.5% worldwide) are related to Genghis Khan

8% of men across parts of Asia (and 0.5% worldwide) are related to Genghis Khan

In the 13th Century, when Genghis Khan lived, birth control had not yet become a topical issue. Certainly not for those nomads traversing the wild steppes of Mongolia.

The Mongolian ruler was equally famed for his fertility as for his military conquests. Khan believed that to leave a lasting legacy (and sustain familial loyalty among Mongolian troops) a ruler had to produce offspring. In his case, many offspring.

Genghis Khan is reputed to have spawned hundreds of children. Most of them sons by different women. Recent studies by evolutionary geneticists suggest that there is now DNA evidence to support these claims. By tracing the Y-chromosome lineage back to that era and placing it in the region and time of Genghis Khan, the evidence suggests that Khan (and powerful male leaders like him), who would have prevailed over a social system that at the time permitted powerful male leaders to produce children with many women, is a strong candidate for the start of the male lineage which today spawns millions of men across Asia and, to a lesser degree, the wider world.

Source:

Nature