STUDY OF MUONS PARTICLE COULD CHANGE SCIENCE AS WE KNOW IT

You may never have heard of muons before, but these particles are crucial to our understanding of the universe. In a milestone study published in the journal Nature, researchers announced that they have overcome one of the biggest challenges to studying these fundamental particles. The study heralds a new era of research into the properties and structure of matter and that includes us, humans.

Muons are fundamental particles and are very similar to electrons, but 207 times heavier. That means they carry much more energy than electrons. They are crucial to our understanding of our physical world, because they provide information about the properties and structure of matter.

But studying muons is difficult. Fundamental particles like muons (think the neutrino) are only visible at high energies and for microseconds. Physicists have to use particle colliders and accelerators to glimpse their properties. These instruments slam particle beams together at a very high speed and capture data from the resulting explosions, allowing researchers to peek into the subatomic world. This is exactly what physicists have been doing at the Large Hadron Collider, which infamously smashed proton beams together in order to discover and study the theorized Higgs boson, another elusive fundamental particle.

We'd known about muons for many years, but we never managed to put them into a particle accelerator before. Now, after decades of research, Rogers and a team of hundreds of international scientists have outlined how to get closer to creating a first-of-its-kind particle collider that can blast beams of muons at much higher energies than any existing colliders. The invention has the potential to reveal exotic particles that exist only in theory or even entirely new particles scientists had never thought of before.

When you smash beams of particles together, what happens is you make all sorts of exotic new particles, like force carriers or like novel forms of matter, And by looking at all the different sorts of particles which can be created, we can try and understand things about how matter gets stuck together. How matter sticks together is at the basis of our understanding of how everything in the universe is made, because everything is made of matter.

This result is a fundamental landscape change. It doesn’t happen very often. It’s like a Lego piece, to build our future plans. A piece of lego that you can multiply and play with and use to build new things. We can move forward in previously unexplored ways, But a new piece of lego can change how we are going to arrange it.

Despite their obvious importance, colliders like the famous Large Hadron Collider, are massive instruments that cost huge amounts of money and are very hard to build and manage. So far, there is no particle collider designed for muons, which means there is no way of studying and understanding them (even though muons were among the first particles to be ever discovered, in 1936).

For many years the biggest hurdle for studying muons was that we never managed to put them into a particle accelerator. Well, The researchers cracked the problem of “ionization cooling of muons” — basically cooling the smashing beams of particles so they’re easier for current instruments to capture and analyze, rather than having the muons flying all over the place uncontrollably.

The researchers had to develop a technique which can take this messy beam and turn it into a really nice laser-like beam: cooling the beam. So if you imagine the beam is like a hot gas, it's flying along really fast. What we want to do is reduce the temperature of that gas. The temperature of the muons at production is roughly 10 billion degrees Celsius. We're trying to go from this diffused gas to something which is more like a laser beam. Cooling techniques have been discovered before, but they usually take minutes or hours to do. What they had developed is a radically different sort of cooling, which can take effect on timescales of billions of a second.

The muon collider itself would be similar in scale to either the Tevatron, which was a machine which was built at Fermilab near Chicago, or the Large Hadron Collider. You're looking at a machine which is several kilometres in length, with these extremely strong magnets, and the cost scale is similar to those machines.

Muons themselves are interesting beasts and there are applications which we will really only just starting to understand if we start building beyond accelerators. Muons' properties hint at these future applications. For example, muons are much more penetrating than X-rays, which means they can be used to look inside things that are too thick for x-rays to image. This includes pyramids and volcanoes, for example.

Muons may provide a completely new way to reach further into the energy frontier of particle accelerators that simply cannot be achieved at the present time, and we might not have a way to get there otherwise. But while the study represents a milestone along the road to developing the first-ever muon colliders, don't hold your breath too soon. There are many more years of research ahead for Rogers’ team to turn this into a reality, he says. But when we do get there, what we find may be truly unimaginable.

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What Is Aerogel?

Aerogel is a synthetic porous ultralight material derived from a gel, in which the liquid component for the gel has been replaced with a gas. The result is a solid with extremely low density and low thermal conductivity. Nicknames include frozen smoke, solid smoke, solid air, solid cloud, blue smoke owing to its translucent nature and the way light scatters in the material.

Aerogels are a diverse class of porous, solid materials that exhibit an uncanny array of extreme materials properties. Most notably aerogels are known for their extremely low densities (which range from 0.0011 to ~0.5 g cm-3). In fact, the lowest density solid materials that have ever been produced are all aerogels, including a silica aerogel that as produced was only three times heavier than air, and could be made lighter than air by evacuating the air out of its pores.

An aerogel is the intact, dry, ultralow density, porous solid framework of a gel (that is, the part that gives a gel its solid-like cohesiveness) isolated from the gel’s liquid component (which takes up most of the volume in the gel).

The term aerogel does not refer to a particular substance, but rather to a geometry which a substance can take on–the same way a sculpture can be made out of clay, plastic, paper-mâché, etc.

Aerogels can be made of a wide variety of substances, including: silica, Most of the transition metal oxides (for example, iron oxide), Most of the lanthanide and actinide metal oxides (for example, praseodymium oxide), Several main group metal oxides (for example, tin oxide), Organic polymers (such as resorcinol-formaldehyde, phenol-formaldehyde, polyacrylates, polystyrenes, polyurethanes, and epoxies),  Biological polymers (such as gelatin, pectin, and agar agar), Semiconductor nanostructures (such as cadmium selenide quantum dots), Carbon, Carbon nanotubes, Metals (such as copper and gold).

Many aerogels boast a combination of impressive materials properties that no other materials possess simultaneously. Specific formulations of aerogels hold records for the lowest bulk density of any known material (as low as 0.0011 g cm-3), the lowest mean free path of diffusion of any solid material, the highest specific surface area of any monolithic (non-powder) material (up to 3200 m2 g-1), the lowest dielectric constant of any solid material, and the slowest speed of sound through any solid material. It is important to note that not all aerogels have record properties.

By tailoring the production process, many of the properties of an aerogel can be adjusted. Bulk density is a good example of this, adjusted simply by making a more or less concentrated precursor gel. The thermal conductivity of an aerogel can be also be adjusted this way since thermal conductivity is related to density. 

Typically, aerogels exhibit bulk densities ranging from 0.5 to 0.01 g cm-3 and surface areas ranging from 100 to 1000 m2 g-1, depending of course on the composition of the aerogel and the density of the precursor gel used to make the aerogel. Other properties such as transparency, colour, mechanical strength and susceptibility to water depend primarily on the composition of the aerogel.

For example, silica aerogels, which are the most widely researched type of aerogel, are usually transparent with a characteristic blue cast due to Rayleigh scattering of the short wavelengths of light off of nanoparticles that make up the aerogel’s framework. Carbon aerogels, on the other hand, are totally opaque and black. Furthermore, iron oxide aerogels are just barely translucent and can be either rust-coloured or yellow. 

As another example, low-density (<0.1 g cm-3) inorganic aerogels are both excellent thermal insulators and excellent dielectric materials (electrical insulators), whereas most carbon aerogels are both good thermal insulators and electrical conductors. Thus it can be seen that by adjusting processing parameters and exploring new compositions, we can make materials with a versatile range of properties and abilities.

Its unique properties have made aerogel popular with a range of industries. Silicon manufacturers, homebuilding materials manufacturers and space agencies have all put aerogel to use. Its popularity has only been hindered by cost, though there is an increasingly successful push to create aerogels that are cost-efficient. In the meantime, aerogels can be found in a range of products: Wetsuits, Firefighter Suits, Skylights, Windows, Rockets, Paints, Cosmetics, Nuclear weapons.

Because of aerogel's unique structure, its use as an insulator a no-brainer. The super-insulating air pockets with the aerogel's structure almost entirely counteract the three methods of heat transfer: convection, conduction and radiation. 

Even though aerogel is still quite expensive, the good news is that studies have shown that aerogel insulation used in wall framing and hard-to-insulate areas such as window flashing can save a homeowner up to $750 per year. In addition to helping homeowners save money, aerogel insulation can significantly reduce your carbon footprint.

Companies are racing to find a way to bring costs down, but for now, aerogels are more affordable for NASA than the general public. Still, aerogels are put to use by construction companies, power plants and refineries.

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What Is Game Theory?

Game theory as we know it today came about in part because of one man’s interest in poker. This man was not just your average man on the street. He was a mathematician, physicist and computer scientist named John von Neumann. 

His goal was loftier than becoming a better poker player. He was only interested in poker because he saw it as a path toward developing the mathematics of life itself. He wanted a general theory – he called it ‘Game Theory’ – that could be applied to diplomacy, war, love, evolution or business strategy.

He moved closer toward that goal when he collaborated with economist Oskar Morgenstern on a book called "A Theory of Games and Economic Behavior" in 1944.

The Library of Economics and Liberty (Econlib) states that in their book, von Neumann and Morgenstern asserted that any economic situation could be defined as the outcome of a game between two or more players.

What is a game according to game theory? Yale economics professor Ben Polak notes a game has three basic components: players, strategies and payoffs. As we just mentioned, game theory applies to games involving two or more players. In a game, players share “common knowledge” of the rules, available strategies, and possible payoffs of a game. However, it is not always the case that players have “perfect” knowledge of these elements of a game.

Strategies are the actions that players take in a game. The strategy is at the heart of the game theory. The theory presented in A Theory of Games and Economic Behavior as the mathematical modelling of a strategic interaction between rational adversaries, where each side’s actions would depend on what the other side would do.

The concept of strategic interdependence – the actions of one player influencing the actions of the other players – is one important aspect of von Neumann’s version of game theory that is still relevant today.

Then there are payoffs, which one source describes as the “outcome of the strategy applied by the player.” Payoffs could be a wide range of things depending on the game. It could be profits, a peace treaty or getting a great deal on a land.

One limitation of Von Neumann’s version of game theory is that it focused on finding optimal strategies for one type of game called a zero-sum game. In a zero-sum game, one player's loss is the other player's gain. A source notes that players can neither increase nor decrease the available resources in zero-sum games.

Critics have noted that life is often not as simple as a zero-sum game. More complicated game scenarios are possible in the real world. For example, players can do things like find more resources or form coalitions that increase the gains of several players. Game theory has evolved to analyze a wider range of games such as combinatorial games and differential games, but we have time to look at only one.

A classic example of a game often studied in game theory is called The Prisoner’s Dilemma. There are two prisoners, Jack and Tom, who have just been captured for robbing a bank. The police don't have enough evidence to convict them but know that they committed the crime.

They put Jack and Tom in separate inter[r]ogation rooms and lay out the consequences: If both Jack and Tom confess they will each get 10 years in prison. If one confesses and the other doesn't, the one who confessed will go free and the other will spend 20 years in prison. If neither person confesses, they will both get 5 years for a different crime they were wanted for.

The Prisoner’s Dilemma contains the basic elements of a game. The two players are Jack and Tom. There are two strategies available to them: confess or don’t confess. The payoffs of the game range from going free to serving 5,10, or 20 years in prison.

Let's see and compare these outcomes (payoffs) As they are put into a matrix: Since Tom's strategies are listed in rows or the x-axis, his payoffs are listed first. Jack's payoffs are listed second because his strategies are in columns or on the y-axis. ‘C’ means ‘confess’ and ‘NC’ means ‘not confess.’ This matrix is called ‘Normal Form’ in game theory.

Moves are simultaneous, which means that neither player knows the other's decision and decisions are made at the same time. In this example, both prisoners are in separate rooms and won't be let out until they have both made their decision. 

One common solution to simultaneous games is known as the “dominant strategy.”  It is defined as the “strategy that has the best payoff no matter what the other player chooses.” Tom does not know if Jack will confess or not. He takes a look at his options. If Jack confesses and Tom does not, Tom will get 20 years in prison. If both Jack and Tom confess, Tom will get only 10 years. If Jack does not confess and Tom does, Tom will go free. 

The best strategy for Tom is to confess because it leads to the best payoffs regardless of Jack’s actions. Confessing will cause Tom to either go free or serve less prison time than if he did not confess. Jack is in the same situation and has the same options as Tom. As a result, the best strategy for Jack is also to confess because it leads to the same best payoffs that Tom will get.

One study states that a dominant strategy equilibrium is reached when each player chooses their own dominant strategy. Why is the strategy of both not confessing not the best choice? While this option would give both of them less prison time than if they confessed, it would work only if each of them could be sure the other one would not confess.

It is unknown whether Tom and Jack would be able to work together with that level of cooperation. In addition, both are unlikely to choose the strategy of not confessing because it has a greater penalty than they would get if they confessed. Confessing also gives each of them the possibility of serving no prison time, which is even less than 5 years in prison.

The Prisoner’s Dilemma is a good example of how rationality can be problematic in game theory. The University of British Columbia, Vancouver researcher Yamin Htun calls it “one of the most debatable issues in game theory.” 

Htun points out that almost all of the theories are based on the assumption that agents are rational players who strive to maximize their utilities (payoffs).  Yet studies demonstrate that players do not always act rationally and that “the conclusions of rational analysis sometimes fail to conform to reality.

As we can see from this game, the most rational strategy that would give both players less prison time was not the best choice, while a choice that involves both players doing more prison time was.

The Prisoner’s Dilemma also reflects how other game theorists were able to fix some of the problems with Von Neumann’s version of game theory. One of them was mathematician John Nash.

He found a way to determine optimal strategies in any finite game. He describes the Nash equilibrium as a particular solution to games—one marked by the fact that each player is making out the best he or she possibly can, given the strategies being employed by all of the other players. 

When Nash equilibrium is reached in a game, none of the players wants to change to another strategy because doing so will lead to a worse outcome than the current strategy. In the Prisoner’s Dilemma, the Nash equilibrium is the strategy of both players confessing. There is no other better option for either player to switch to.

From this game, we can also see another interesting aspect of the Nash equilibrium. Mathematician Iztok Hozo points out that any dominant strategy equilibrium is also a Nash equilibrium. He explains that this is because the Nash equilibrium is an extension of the concepts of dominant strategy equilibrium. However, he notes that the Nash equilibrium can be used to solve games that do not have a dominant strategy.

Nash received great praise for the Nash equilibrium and his other work in game theory – but not from John von Neumann. According to Forbes, “Von Neumann, consumed with envy, dismissed the young Nash's result as ‘trivial’-- meaning mathematically simple.” 

Others did not share in Von Neumann’s assessment of Nash’s work. Nash, Reinhard Selten, and John Harsanyi went on to share the 1994 Nobel Memorial Prize in Economic Sciences for their work in game theory. 

Nash’s most fundamental contribution to game theory was in opening the field up to a wider range of applications and different scenarios to be studied. Without his breakthrough, much of what followed in game theory might not have been possible.

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Did The Big Bang Created All The Elements In Periodic Table?

My absolute favourite fact in the universe is that we are made of dead stars. And that's literally true. The atoms in our bodies were actually created inside the cause of stars that then exploded and died or unravelled into space. And so the question about the periodic table is very interesting. What was the periodic table like at the beginning of the universe, the moment of the Big Bang?

Well, one thing Astronomers say is that it was a lot simpler. The Big Bang, when it went off, produced basically three elements. Almost everything was hydrogen. There was a little bit of helium, and a tiny, tiny little smattering of lithium as well. So those three elements were around just a couple of minutes after the formation of the universe, but nothing else.

And that's actually not a theory. That's actually something we can observe. One of the wonderful things about being an astronomer is, as you look out into space, farther and farther away, the light has taken longer to get to you. And the farthest we can see is actually back to a time only about 400,000 years after the Big Bang.

At that time, there was nothing but very hot hydrogen gas, and a little bit of helium and lithium as well. So everything larger than that, every atom more complex had to be formed inside a star. Over time, stars like the sun are pretty good, over the life cycle, at producing things like carbon and oxygen. They don't really get much more far off the periodic table than that. 

If you want to go any farther than the element, iron, you actually need a very violent explosion, a supernova explosion. The cores of very massive stars and by that, I mean stars that are 10, 20, maybe even as much as 50 times the mass of the sun, their cores are much hotter, because the gravity crushes things down and the temperature goes up many, many millions of degrees hotter than inside the sun. So these stars can actually form bigger and bigger atoms.

The hotter the temperature, the denser the core, the more you can ram things together and actually, form bigger and bigger atoms over time. But there's a very special thing that happens when you get to the atom, iron. And it's something you have actually heard about but you may never have thought of.

When people think about getting energy out of a nuclear reaction-- you've heard about fusion reactions. So like a fusion bomb, actually, takes hydrogen, fuses it together to make helium and that creates energy. The sun also runs on that particular reaction, fusing hydrogen together.

Then you also heard that there's something called fission. And this is how, say, a uranium bomb would work. A uranium nucleus has many, many particles inside it you actually get energy out of breaking it up and forming two smaller nuclei that are actually a bit denser and they hold together better. And so you get energy out of breaking them apart.

So, the element, iron, is exactly halfway between those two processes. So you have been getting energy by fusing things together until you get to iron. And iron is the first nucleus where you don't get any energy out of fusing. From anything bigger, now, you get energy out of ripping apart, fission. 

So iron is what sets off a supernova explosion. When a star tries to fuse iron together, it absorbs energy. And that's not great for the star. The core collapses. And that huge collapse creates this giant wave of heat and the formation of many, many new elements after that. So anything heavier than iron has to be created in a supernova explosion.

Now, there are some elements, heavier still, that even supernova energies don't really get up quite high enough to make. And this is something we only found out recently, in the last couple of years. Elements like gold, platinum, bismuth and all the big things, like uranium and all of the really large atoms; they have to be formed by something that seems almost preposterous, but we have observed this happening-- two neutron stars colliding.

So neutron stars are the cores of dead stars. They are super-compressed. The density of a neutron star is about a Mount Everest worth of mass in every square centimetre. So think about crushing Mount Everest into a little cube. The entire star, which is only about 10 miles across, is actually that density. And that means you have a tremendous amount of nuclear components neutrons, protons really close together. And two neutron stars collide.

When that happens, you make all of these very heavy elements up, like gold, and platinum, uranium and all the big stuff. And again, this is not something that we just know theoretically. We actually have observed this happening. Recently, we observed two neutron stars colliding. And in that single explosion, 10,000 times the mass of the Earth in gold came out of that explosion. It was tremendous. So, we definitely know where those atoms come from now. We observed that happening. 

So to recap, at the beginning of the universe, you had three elements mostly hydrogen, a little bit of helium, a tiny bit of lithium. Now we have the entire periodic table. And a lot of those are formed in stars like the sun. Anything past iron has to be formed much more violently, in a supernova explosion or in the case of very large atoms, two colliding neutron stars. And over billions of years, we have filled out the periodic table that way.

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What is Time?

Time is something that everyone is familiar with 60 seconds is one minute, 60 minutes is one hour, 24 hours is one day and so on. This is known as Linear Time and is something that everyone is familiar with and agrees upon. But consider this, if someone came up to you on the street and asked you to draw time, what would you draw?

You might draw a clock, or a watch ticking every second, Or you might draw a calendar with X's over each day to represent the passing of time. But that's all those drawings would be, just physical representations of the passing of time. Those drawings would just scrape the surface of the Enigma that is time. Something that seemingly runs our lives and is unavoidable can't be explained by even the smartest people on Earth. So what is time and can we prove that time even exists?

Aristotle once said, "Time is the most unknown of all unknown things." That was nearly 2,500 years ago, and it still stands true today. If you were to go to Google and type in, "What is time?", you would find that it says time is a dimension and in many ways it is. When you text a friend and ask them to meet for coffee, you wouldn't give them a place without a specific time.

However, there is a flaw in that definition of time; It leaves too many doors unopened - because time is also a measurement. For example, I was born in the 1990s. That was over 20 years ago If I were to say I was born 18 billion kilometres in the past, that wouldn't make much sense and people would probably look at me like I'm crazy.

With spatial dimensions - the 3D world that we live in - it's very easy to go back and forth between places because these things are essentially fixed in space. If I went to the store to buy groceries and I forgot the milk, I could easily go back and buy some milk. However, the time that it took to do that is unable to be retrieved. It is lost forever into the past.

An object placed in 3D space will stay there almost indefinitely. If I place a bottle on the table, it will just stay there, but that bottle still falls victim to time. See, time is like an arrow - it moves in one direction; forward. Scientists fittingly called this the arrow of time.

If you one day woke up and found yourself floating in the middle of empty space, would you be able to tell which way is up, down, left or right? Probably not. However, time is a much simpler ordeal. See, the time comes from the past, originating at the Big Bang, where our history lies and is fixed.

Through the present, where we are essentially prisoners of, towards the unknown and turbulent future. We can remember things from the past like how I can tell you that this morning I went to the store, bought groceries and then forgot to buy milk. But at the same time, I can't tell you what I ate for breakfast next Thursday.

The arrow of time originated at the Big Bang and has been moving forward ever since. We used the second law of thermodynamics to represent this. It is known as entropy. Think of entropy as a measure of disorder in the universe. 

At The Big Bang, all the matter in the universe was compacted into an infinitely small point. This is considered a very low entropy situation; a very orderly situation. It would be similar to stuffing every sock that was ever made into one drawer. In that situation, you know with 100% certainty where your socks would be. Ever since the Big Bang, all the matter in the universe has been expanding away from each other making the universe a higher entropy system. 

Because of entropy and because of the arrow of time, we have galaxies, stars, planets, and even life. Entropy is the reason that you can tell the difference between the past and the future. It explains why every human is born and then they live and then dies - always in that order. If there were no entropy -- if there were no change in the universe, you wouldn't be able to tell the difference between the year 2017 and the year 1 billion. No matter what you do, time moves forward and doesn't stop for anyone or anything.

At least on the macro scale. See, the arrow of time works and is extremely noticeable on large scales the skills that you and I operate on every day. But at a quantum level time operates differently. Take the situation where you woke up in the middle of space. There, you have no idea which way is up, down, left or right. It's a very unique situation that only applies in the vastness of empty space, but if you come back to Earth, it's very easy for you to orient yourself. The arrow of time works in a similar way. On a macro level -- the big level, it's very easy for you to tell that the year 1900 is different from the year 2018. It's very easy to view the flow of time.

However, on a micro scale, if we look at deep down into the physics that make up the universe, entropy and - subsequently - the time isn't so obvious. If I were to record myself cracking an egg and pouring its guts into a bowl and then I reversed the footage, you would easily be able to tell that the footage had been reversed. However, if I record a pendulum swinging back and forth for five minutes and then reversed the footage and show it to a random person on the street, will they be able to tell that that footage has been reversed? The answer is probably not.

See the arrow of time seems to flow in one direction on the macro scale, but as you take parts of it away and skim it down to the bare bones of particles that make up the universe, time seems to work and flow in every direction; both forward and backward. There are no laws of physics that state the past is any different from the future.

The only reason why you can think about what you want to have for dinner tomorrow as opposed to what you want to have for dinner yesterday is because of the arrow of time; because of entropy, because the universe had a beginning. Or at least it seems like it.

You might be starting to see why the arrow of time and entropy are so important. They quite literally govern our lives and the universe. See the fact that entropy is increasing is well known. It's the reason why life today is the way that it is.

However, not many people are addressing the question that is: "Why was the entropy of the universe so low in the first place?" Well, the answer is simple. It was lower yesterday than it was today. You can take this logic all the way back to the Big Bang. You hear that a lot, "The universe came into being at the instance of the Big Bang." And for all we know as of now that may be true. However, it might not be true.

We have the physics of Einstein's general relativity that allows us to go back to mere seconds after the Big Bang. But after that, our equations break down. That is as far as we can go for now. There is no law of physics yet that states that there wasn't time before the Big Bang and perhaps a reversed arrow of time. We just don't have the science to look that far back yet.

Because the universe is expanding and because entropy is increasing with time, there will eventually be a time where everything in the universe is so far apart from one another that space will essentially be empty. Everything will be too far apart to interact with one another all the way down to the atoms that make up everything in the universe.

However, just as the temperature outside fluctuates day to day, so does the entropy of the universe. Albeit, very small fluctuations are small time scales such as a human life, over unreal time scale such as 10 to the 10 to the 10 to the 56 years. It is possible that quantum fluctuations could cause an extremely random extreme entropy decrease. This would create conditions similar to the Big Bang as we know it and could explain the arrow of time and the origin of our universe.

However, in order to answer these questions, we need to unite quantum mechanics with Einstein's general relativity. This would provide a scientific link between the quantum world of atoms with the macro world of stars, galaxies and black holes in the universe. This is dubbed "the theory of everything" and is something that many scientists are working on right now.

With this theory, we may be able to - for the first time - be able to explain how and why the universe we live in came into existence. And maybe, even prove that the multiverse exists.

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Internet

Today about 4.2 billion people have access to a world of information never before seen. Such an extraordinary level of connectedness has revolutionized everything from science and technology to commerce and romance, and virtually every aspect of our lives. 

Above all the technological innovations in history, few have made as strong of an impact as the internet. Comprised of a global network of computers, the internet allows for the transmission of information and connectivity at an unprecedented speed and scale. Some of the first computer networks began in the 1950s and 60s, but unlike today's global network these early networks were centralized within certain businesses and agencies.  It wasn't until 1969 when centralized computer networks became connected.

Funded by the US Department of Defense and developed by universities this host to host network connection called ARPANET. A direct ancestor of the internet ARPANET was the first of its kind. The network grew and by the 1980s incorporated networks at research institutions and other US federal agencies such as the National Science Foundation or NSF. The NSF connected these disparate networks into one large one NSFNET, which shifted over from being a federally run network to a commercial enterprise for Internet service providers.

By the late 1990s, this shift along with the rise of personal computers the world wide web and web browsers allowed the general public to access the Internet for the very first time. Today computers, smartphones, televisions, video game, consoles and other devices all tap into the network and transmit and receive data almost instantly. 

By clicking send in a messaging apps text audio and video are converted into pieces of electronic data called packets. These packets are then tagged with a port number and IP address, much like the mailing address on an envelope. The port number and IP address direct the packets to a given destination on the internet. From there the packets may travel over Wi-Fi cellular data or an Ethernet or phone line, through a series of routers modems and servers then through fibre optic cables or satellites. And through a similar process in Reverse to reach the packet's destination. Once the packets arrive their data is reassembled into the text audio or video that was originally sent. 

Since the days of the earliest computer networks, the internet has undergone a tremendous transformation, while also transforming the world that created it. From a closed off network to one that covers the globe, the Internet has provided access to information to every continent connecting people and ideas like never before.

Also Read:- Mystery Around Hypatia Stone

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Pulsed Plasma Thrusters

While travelling in space, one of the hardest things to do is to stop or change direction. Without anything to push against or friction to slow things down, spacecraft need to do all the hard work of changing their speed or path by there thrusters. And sometimes they do that in ways you would never expect: like by vaporizing Teflon. They are called pulsed plasma thrusters and they can use the same stuff that’s on your frying pan to make spacecraft zoom around the universe. And they have been doing it since the 1960s.

To make basically any move in space, satellites rely on Isaac Newton’s famous Third Law of Motion, which is probably on a poster in every high school physics classroom: For every action, there is an equal and opposite reaction. Put another way: throw stuff backwards and you will go forward. In fact, you can boil down every rocket design, no matter how complicated, to this basic idea. When thinking of a rocket, you might normally imagine the chemical propulsion. That’s the “fire-coming-out-the-end” kind, which uses a controlled explosion to hurl material out the back of the rocket. 

But once in space, another kind, electromagnetic or EM propulsion, also becomes available. They are not strong enough to get rockets off the ground, but they are great once you are past most of Earth’s atmosphere. These rockets work kind of like railguns, accelerating charged particles or ions, out the back with electric or magnetic fields. Today, we have all kinds of EM thrusters, but pulsed plasma thrusters, or PPTs, were the first ones ever flown in space.

They were used in 1964 on the Soviet Zond 2 mission to Mars. Like some other engines, PPTs specifically use plasma to generate thrust, instead of a random collection of ions. Plasma is a super hot substance made of charged ions and it is the fourth state of matter. In some ways, it behaves kind of like gas, because its atoms are pretty spread out. But unlike the other states of matter, plasmas can be shaped and directed by electric and magnetic fields.

To generate its plasma, PPTs eat Teflon! Which is pretty awesome. A pulsed plasma thruster places a block of Polytetrafluoroethylene what we know as Teflon between a pair of metal plates. Then, connected wires charge up those plates with electricity until it arcs through the Teflon block, set off by a spark plug. That arc delivers thousands of volts into the block, vaporizing the nearby Teflon and ionizing it into a plasma. The sudden burst of plasma effectively creates a circuit connecting the metal plates, which allows electricity to flow like it is travelling through a wire.

One neat side effect of flowing electricity is that it generates a magnetic field. And everything in the thruster is already arranged so that this field pushes the plasma out into space. At this point Newton’s third law springs into action, pushing the spacecraft in the opposite direction of the departing particles.

Well, this kind of thruster produces a very tiniest bit of motion. A pulsed plasma thruster deployed by NASA in 2000 produced an amount of force equal to the weight of a single Post-it Note sitting on your hand. Which might not seem that exciting, but it has some big implications. Like other forms of electromagnetic propulsion, these engines require a lot of electricity to run, but in exchange, they offer incredible efficiency with their fuel.

Pulsed plasma thrusters can produce up to five times more impulse or change in momentum for every gram of fuel than a typical chemical rocket. They do it very, very slowly, but they get the job done. PPTs also offer exceptional simplicity and safety. The only “moving part” is a spring that constantly pushes the Teflon block forward and without the need to store pressurized liquid or gas fuel, there is no chance of explosion. So it makes sense then that pulsed plasma thrusters were so useful back in the 1960s. Since then, their lack of power has meant that most spacecraft main engines have remained chemical. And when companies really need some kind of EM drive like for the Dawn mission to the asteroid belt they will tend to choose more sophisticated designs. But that doesn’t mean we are done with these thrusters just yet.

Recently, their extreme simplicity has made them a natural fit for the most up-and-coming field of exploration: CubeSats. CubeSats are tiny, shoebox-sized satellites designed for simple missions and built on the smallest of budgets often by research labs or universities. Earth-orbiting CubeSats seem almost tailor-made for the strengths of pulsed plasma thrusters. Lots of sunlight gives them ample electric power, but since they are so small, space and weight are at an absolute minimum. And right now, most CubeSats typically don’t have any kind of propulsion system of their own.

So one solution is micro pulsed plasma thrusters, which can weigh just a few hundred grams and measure under 10 centimetres on a side. That might not sound like much, but even a tiny amount of thrust could double the useful life of some kinds of CubeSats. They will likely need to undergo more testing and development before they are ready for primetime, but someday, we could have a whole fleet of Teflon-eating satellites.

Also Read:-  Let's Understand Black Hole

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Can Gravity Beat Dark Energy?

Although it might not seem obvious when you look at the night sky, but we live in a universe that is expanding faster by the instant. Every day, stars fall over the horizon of what we can see, as the space between us stretches faster than their light can reach us. And we can never know what exists past that horizon. So you might imagine or you might have heard about, a far-off future, where space is stretching faster and faster and where all of the stars and galaxies are over that edge. A future where Earth will be left with a dark, empty sky. But luckily for us, or, at least, for hypothetical future earthlings, that’s not actually the case. Because the universe is expanding but not all of it.

We have known that the universe is expanding since the 1920s, but we only discovered that the expansion is accelerating in the 1990s, thanks to the Hubble Space Telescope. Hubble was the first tool to measure really precise distances to supernovas out near the edge of the observable universe. And it showed us that out there, ancient galaxies and the supernovas in them are zooming away from us faster than anywhere else. In fact, astronomers realized that they were flying away even faster than expected. Which, at first, didn’t make sense.

At the time, we thought the universe was dominated by gravity, which pulls things together. So seeing everything accelerate apart was weird. It would kind of be like if you kicked a ball uphill and saw it speed up instead of coming back down to you. Because of this, scientists concluded that there had to be something else going on, something pushing these galaxies apart. They came to call that thing dark energy. Decades later, dark energy is still really mysterious and there is a lot we don’t understand about it.

One explanation is that it’s a property of empty space. This means that space itself, with no stuff in it at all, has dark energy. And that energy pushes space apart, creating new space, which in turn has dark energy, which pushes space apart, creating new space, which in turn has dark energy, which You get it. If dark energy is a property of space, that also means you can’t dilute it. Its density will always be the same, no matter how much space expands.

Of course, that density is also pretty small. If you borrow Einstein’s “E=mc2” trick and express energy as mass, it is equivalent to about one grain of sand in a space the size of the entire Earth. But if you average that over the whole universe, which is mostly empty space, there is more dark energy than anything else. So it dominates and the universe as a whole expands. That’s why the most ancient galaxies are also moving away faster than before.

It has taken a long time for their light to reach us, so the universe has had more time to stretch. Now, this might all make dark energy seem super strong. After all, it makes up more than two-thirds of all the stuff in the universe and it’s pushing apart entire galaxies. But it is only powerful because there is a lot of it.

Within small spaces, especially those full of planets and stars, dark energy is actually pretty weak. Like, the gravity between the Sun and the Earth or the Earth and the Moon is more than enough to overpower the repulsive dark energy between them. In fact, most of the universe’s mass is concentrated in galaxy clusters and these pockets of matter are completely immune to dark energy. They are simply not expanding. 

It doesn’t mean the expansion is negligible, like how technically your gravity pulls ever-so-slightly on Earth but it is not enough to actually notice. It means that, as far as we know, dark energy is truly not stretching our galaxy at all. This is because it’s not a force like gravity, so it works a little differently.

To understand how, think about pushing on a heavy door. If you push lightly, it won’t open. Push a little harder and it still won’t. But if you push hard enough, once you cross a certain threshold of pushing, it will open. That door is gravity and within a galaxy, there’s just not enough dark energy to push it open. 

In other words, gravity is too strong. So our galaxy will never expand, because if it can’t stretch even a little, then it can’t create more space. And that means the amount of dark energy inside will never grow. Of course, this isn’t something we have been able to directly observe, like by looking at other galaxies. But multiple observations have shown us what dark energy is like and they all suggest this should be true.

Eventually, in the really distant future, fewer and fewer galaxies will be visible from Earth. And in 100 billion years or so deep space will be almost empty. But if Earth were still around by then, which, admittedly, is pretty unlikely, we would still have a beautiful night sky. Even as the universe stretches, the glow of our galaxy will still be overhead and we will have stars, constellations and even a handful of galaxies bound by gravity to ours. All because dark energy just can’t get a foothold around here. Of course, this will only last until the heat death of the universe but that’s another story.

Also Read:- The Big Rip Due To Dark Energy

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The Big Rip Due To Dark Energy

Even though nobody else will be around to see it, scientists are fascinated by the end of the universe. It is kind of like the Big Bang there's just something so interesting about knowing where your atoms came from and where they are ultimately going to go in billions of years. Right now, there are a few ideas about how everything could end, where everything is spread so thin that activity basically stops.

Except, based on the results from a paper published in Nature Astronomy, that might not actually be true. Instead, there is a chance that everything in existence will eventually be ripped apart. And it would all be thanks to dark energy. Scientists think it makes up about 70% of the stuff in the universe and that it is the reason the expansion of the universe is accelerating. But there is a lot they are still figuring out.

Some of their research into dark energy has involved tools called standard candles. Standard candles are objects or events of known brightness that are used to measure distance in the far-off universe. Essentially, if you know how bright something should be up close, then how bright it actually looks indicates how far away it is.

For decades, the most important standard candle has been a special kind of exploding star called a type a supernova. These events always have the same brightness and in the 1990s, they allowed scientists to discover that the universe’s rate of expansion was accelerating. But what is really important for this recent study is that all the estimates provided by type 1a supernovas also indicate that the density of dark energy is fixed.

There is a lot of math involved, but this fact is a big reason they believe the Big Freeze is most likely. The problem is, you can only see so far with any given candle before it gets too dim and type 1a can’t take us back to the beginning of the universe. Because light can only move so fast, looking deep into space is like looking back in time. And these supernovas only allow us to see what things were like 4.5 billion years or so after the Big Bang.

Admittedly, there are some data sources like one called the Cosmic Microwave Background, that can tell us what things were like around 400 thousand years after the Big Bang. But that Background actually seems to disagree with what supernovas say about the expansion rate, which has had astronomers debating different options for years. There is also been a 4-billion-year gap between the two data sources, so it has been hard to figure out what’s going on.

That’s where last week’s news comes in. In their paper, a pair of astronomers proposed a new kind of standard candle, one that can let us peer back to that sweet spot just 1-2 billion years after the Big Bang. Their idea relies on quasars, rapidly-growing black holes that are among the universe’s brightest objects. Although quasars vary a lot in brightness, the authors claim that the ratio of ultraviolet brightness to X-ray brightness is not only more predictable but also reliable enough to indicate a quasar’s distance.

They point out that, at distances where both type 1a supernovas and quasars are visible, they provide comparable results, too. But the key is, farther from Earth, and further back in time, only quasars are visible. And after looking at some of those super-distant objects, the authors claim to have made a surprising observation: In the first couple billion years after the Big Bang, the growth rate of the universe didn’t match the predictions made by the supernova-based models. Back then, things seemed to be getting bigger more slowly than expected.

That implies that the amount of dark energy driving that expansion hasn’t been constant after all. Instead, it has been increasing over time. It sounds like a wild idea, but it would help explain why there isn’t a perfect match between the expansion rate we see from supernovas and that of Cosmic Microwave Background. So it is not like there is no foundation for it. But still, before they rewrite your Astronomy textbook, it is important to remember two things. One, these results will need a lot of confirmation before they are accepted into the mainstream theory. And two, scientists have effectively no clue what dark energy actually is.

So it is not even worth asking questions like what would be generating more and more of it, because we don’t even know what IT is. But if these results are true, there is one thing we do know, instead of ending in the Big Freeze, the universe would eventually end in the so-called Big Rip, where ever-increasing dark energy tears apart every particle until there’s nothing left and no one to see it. But the assumption is that it’s not such a big deal, because there is no way we would be around by then.

Reference:- Quasars as standard candles
Also Read:- Let's Understand Wormholes

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