Invisibility

Have you ever heard of the magical Invisibility Cloak from Harry Potter. I know, it is very much fiction, hence the magic part. But, what if we could render a three-dimensional object invisible using something other than magic?  Well, that is exactly what the U.S. Department of Energy at the Berkeley Laboratory have done, with the creation of a thin cloak which when placed on a object will mould to it and leave it impossible to detect with visible light (the stuff we use to see!). You see instead of magic scientists are using physics to create Invisibility Cloaks. However, on the downside, unlike Harry's Cloak, the one designed by scientists is so small that it could maybe shield a couple of your cells, not your entire body. 

The cloak is made of little building blocks of gold Nano antennas and is about 80 nanometers thick. The principal is light reflection, wherein the light is reflected in a way that makes the object appear invisible. The metamaterials that make up the cloak (also called a skin) can bend the light, altering it's behaviour.  *Metamaterials are very organized structures and really exceed normal everyday materials. They are commonly made with a conductor (aka: a metal).

So, other than being microscopic the cloak has other downfalls, like if the observer moves the illusion is gone and the object can be seen. Plus, to actually work on such a bigger scale (like to hide a person from view) the skin would be huge, like four times the person's actual size.

Now, lets talk physics. As mentioned above we see visible light, the light is reflected off an object detected by our eyes and sent to the brain via electrical impulses which makes an image. The frequency of the light is how colour is determined, without the light frequency, we would live in a colourless world.  So, it is easy to make the conclusion that for something to be invisible we need to prevent the light from reaching our eyes. This means there are really only two options, bend the light around the observer (us) or reflect the light preventing it from reaching the observers eyes. In modern times we have a less high tech method and it is camouflage, which if done well enough means that the object is able to blend into the surrounding so that it is impossible to point out. But, camouflage is unable to render something 'invisible', all it can do it make it fit into it's surroundings. 

Lets go back to the special metamaterials which with measurements and some spectacular physics can actually produce a negative index of refraction. The idea is that the metamaterial bends the light waves around itself and the thing it is concealing, which means that no distortions of the electromagnetic waves from the metamateria are detectable by any observer. This principle is not new, there are cloaking devices for different ranges of the electromagnetic spectrum. Metamaterials can conceal and reveal, for instance they can act as lenses, showing us things that are smaller than was thought could possibly be seen, which again goes back to the negative refraction, a unique property of the metamaterial.

Want more history, or even just some cool information on cloaking devices this short video is for you!

Websites Consulted:

http://newscenter.lbl.gov/2015/09/17/making-3d-objects-disappear/

http://www.sciencealert.com/watch-nano-sized-invisibility-cloak-can-make-small-objects-disappear

http://www.physicscentral.com/explore/action/cloaking.cfm

http://discovermagazine.com/2009/apr/10-metamaterial-revolution-new-science-making-anything-disappear
https://www.youtube.com/watch?v=qcTOPFMEEkM

String Theory

WORD WALL:

1. Fermion: a subatomic particle that obey's the description given by Fermi and Dirac. (A particle with a spin that is half of an odd integer and where no more than one particle can exist in the same quantum state). *Obeying the exclusion principle. 
2. Boson: a subatomic particle that obey's the description given by S.N. Bose and Einstein. (A particle with an integral or zero spin that can exist in the same quantum state as another identical particle) *Not obeying the exclusion principle.

String Theory:

String Theory simply looks into particles and their relationship. The point is to try and make sense of how the theory of gravity and quantum physics are connectable. Quantum physics can describe elementary particles but only when gravity is not factored into the equation. Relativity is great at orbits, and evolution of space; however, in order for the theory to be acceptable we need to take away any quantum mechanics that is used to describe Nature. So, in order for these two different theories to fit together science has invented another theory – String Theory. If you are like me then you want to know the simplified version and that is what we will look at in this post.

String Theory is still evolving so all the answers have not yet been found. The main thing to understand is that according to this theory everything is made of energy and strings (vibrating filaments if you want the technical term). Supersymmetry is the relationship between bosons and fermions (particles). Also, the Universe has more dimensions than we normally look at.

All right, so before we get lost in this weird universe that things are made up of little strings we need to understand what a ‘string’ in this sense actually is. Strings are supposed to be the building blocks so, it is better to think of them as the start of everything instead of actually having their own building blocks. Essentially, strings make up the elementary particles (electrons…) that make up everything else. This is all just talk though with no real mathematical proof having been made (at least to my understanding).

Now, if you have not caught on and are thinking ‘but wait maybe strings are made of energy’ – you are sadly wrong. I can say this definitively since electrons or really any other elementary particle is not made of energy, energy is simply a property NOT an actual building block – it would be like saying the electron is made of momentum and this is just to ridiculous.

Now, that we have a grasp on strings we should learn sort of what they are. Strings are to be looked at as 1D objects, they can be liner or looped. Each string is tiny meaning that even with the best-grade science equipment we have going there is just no plausible way to see the strings, instead we would see the predictable point-particle.  The small, minute size allows for the strings to vibrate, and all particles that we have are just variations of vibrating strings.

Lets go back to the basic fundamentals of String Theory and go a little deeper into supersymmetry, which is the concept that every single particle will have a friend. The friend particles are related. The naming is pretty easy, a fermion’s superpartner will have a ‘s’ prefix and a boson's superpartner will have an ‘ino’ suffix. An example; the fermion electron will be partnered with a selectron, the boson proton would be partnered with a photino.

Again, going back to the basics paragraph you may be wondering why we need to imagine more dimensions. The answer is simple for string theory to be mathematically correct there needs to be more than the four dimensions. The scientists who use this theory proposed that these extra dimensions are so tightly compact and small that we just cannot detect them.

In the end, String Theory still has a bunch of unanswered questions however; it is a way for quantum and gravity to work in some sort of weird physics harmony.

Websites Consulted:

http://www.dummies.com/how-to/content/string-theory-for-dummies-cheat-sheet.html

http://www.physlink.com/Education/AskExperts/ae138.cfm

https://www.quora.com/What-are-strings-made-of-in-string-theory

http://www.superstringtheory.com/basics/basic3.html

http://www.thefreedictionary.com/boson

https://i.guim.co.uk/img/static/sysimages/Guardian/Science/contributors/2011/8/28/1314561399991/bosonsandfermionssmall.jpgw=620&q=85&auto=format&sharp=10&s=05b7b7af59d6c7bbeabff4f099ec6110

Come to the Dark Side: We have dark matter!

A few years ago the accepted idea was that gravity was going to gradually slow Universal expansion over time. This was all just talk since no one had any proof that the Universe had begun to recoil in on itself. However in the year 1998 the Hubble Space Telescope found that a supernovae in the distance proved that today the Universe is expanding faster than it was in the past. This defies all the logic of gravity since gravity pulls everything together not apart. There were then three ideas proposed, Albert Einstein’s unaccepted proposition of a Cosmological constant. Which is essentially the constant that explains that space is filled with some kind of energy. It is still unknown whether Einstein was in fact correct however, today we are given a name to the really unknown explanation and that is dark energy.

Dark energy is really not a known thing as stated it is a name given to an unknown. The only fact that is proven is that it is the reason for the Universal expansion.  The weirdest thing is that Dark energy makes up a huge 68% of the entire Universe. Dark matter is equated to about 27%, and the stuff that is physical and observable on Earth makes up only about 5%.

Einstein said that empty space is not just a bunch of nothingness. He though that dark energy could just be the energy that empty space posses.  Actually, dark energy could just be one of the properties of the weird and wonderful space . Dark energy would come in good company with the other strange space properties like space can just become, it can just pop up out of the blue (as far as we know today). This being said, if space is constantly growing then the amount of energy would also increase which leads to the theory that this increase in energy also leads to faster Universal expansion.

The theory that dark energy is just a new kind of dynamical energy field, describes how dark energy basically fills space with the opposite effect of normal energy – aka it makes the universe expand instead of shrink. The people who came up with this actually went as far as labeling it quintessence. But, still the unknowns pile up and quintessence is unable to fully be explored, leaving gaps like why it even exists.

If we really want to throw out all the possibilities we could say that Einstein was wrong in his theory of gravity. This would lead to new theories, which would have to provide a solution to fit dark energy into the gravity equation. The problem is that we do not have any of logical theories, and it would be hard to come up with something so broad that will describe both dark energy and the effects of gravity. *Some theories exist but none appear at all correct.

If you recall the Quantum section, it too has a theory. Proposing that in empty space there are temporary particles that form and then disappear over and over. The calculations for this theory were so wrong however that it is not really the favoured theory – and just makes dark energy a problem even to some of the people looking at very strange physics.

So, now that I’ve rambled on about dark energy you are likely wondering about dark matter. I can tell you that dark matter is not stars or planets, it is not made of the baryons clouds like normal matter, it does not interact with any electromagnetic forces, it never will absorb or reflect light (therefore we cannot see it),  it is not some large black hole , and it is also not antimatter.

Fritz Zwicky discovered the gravitational effects of dark matter way back in the 1930s as he was studying the Coma Cluster and the movement of galaxies within this cluster. There are about 1000 galaxies in the Coma Cluster. Gravity is said to hold the galaxies in this cluster. So, how did his research lead to dark matter? When he looked at the total light output and compared it to the mass of the Cluster the ratio was not adding up to that of the Kapteyn stellar system (the amount of light was less than one single Kapteyn star). This means that the cluster would need to have some unaccounted matter and this matter must be dark matter. At the time this was not one of the main issues, scientists were still worried about other more pressing matters and put the dark matter issue to the side for awhile.

You’re wondering; if we cannot see it how are we so sure it exists. For one I just got done talking about dark energy and it’s effect of gravity, well dark matter has an effect on normal, visible matter.

So what in the world is dark matter? There are theories, for instance dark matter could be made of weird things like axions, or it could be a hidden form of baryonic particles shielded in dense masses of other elements. This is what is referred to as massive compact halo object.

Maybe the strangest thing about dark matter is that it is seen as such an abundant thing that it could literally be passing through/by us every single second. The problem is that is does not have any strong interactive properties, not even with other dark matter.  The fact is that it is hard to study, but also it could literally be anywhere or everywhere however we would not know with the naked eye if it were actually right next to us this very moment.

Websites Consulted:

http://science.nasa.gov/astrophysics/focus-areas/what-is-dark-energy/

 http://www.symmetrymagazine.org/sites/default/files/images/standard/Feature_DarkMatter3.jpg

http://home.cern/about/physics/dark-matter

http://ngm.nationalgeographic.com/2015/01/hidden-cosmos/ferris-text

https://www.learner.org/courses/physics/unit/text.html?unit=10&secNum=2

http://www.symmetrymagazine.org/sites/default/files/images/standard/Feature_DarkMatter3.jpg

http://astronomer.wpengine.netdna-cdn.com/wp-content/uploads/2014/09/DMPie_2013.png
http://www.abmedia.com/astro/CCDMono/Coma-Cluster-130EDF.jpg

Time Dilation

If you have studied High School physics then you should understand that everything depends on where the observer is observing something. When looking at things like time and distance the idea is taken to a new marvellous level.

So, what is time dilation? You could say that stationary equates to slow and moving equates to fast. If we take a look at Albert Einstein the creator of the relativity theory (who by the way in 1907 proposed time dilation), made time travel a theoretical possibility – but only to go to the future never to the past. The idea is that action in space can change and modify time. In space if we were to, I don’t know, reach light speed then we could speed up the passage of time.

Don’t believe me? Well, I have proof! All right, imagine two super clocks (called atomic clocks) flying on two planes going in antiparallel directions; these clocks will show time difference, that directly correspond to their direction of travel. You still think I’m making this up – like how do airplanes prove anything? Do not fret; there are more complex sciency ways to prove time dilation. Like looking at pions and muons (two particles). Both of these babies have proven decaying rates however as they shine down on the earth in cosmic rays they move very, very fast. As they are moving so fast their decaying rates do not appear correct but to a somebody who knows about special relativity this is just another simple calculation. I know some of you will be thanking Einstein after you find out that satellites like the ones providing you with GPS on your long trips can only exist because calculations that incorporate time dilation allow them to do so.  We can give credit to special relativity for the little ability to go on road trips without having to bring a map of the world along. 

Now are you interested in skipping a couple years? Time dilation is the solution for you. Get in a space ship go for a little flyby to one of the trillion stars and bippity boppity boo you come back a few weeks later to realize that a couple years have passed down here on Earth!  The biggest downside is the speed requirement; you need to be going faster then any of us will ever-likely travel in our lifetime. The reason these speeds are so out of reach is acceleration's relationship to mass – as something accelerates it's mass increases to the point that the fuel needed to continue to accelerate is so large that it is just unfeasible with the resources we have today. 

Another thing that this little journey into space is good at explaining is the Twin Paradox. So, to make matters easier pretend you have a doppelgänger (or identical twin). You decide to go into space and he or she is left behind. When you come back you may have aged about a month while they could look like an old folk.  Weird right? 

I know what you are thinking, how could we make time stop? That is a question the universe is not willing to allow us to answer. Think of it as if you are driving your car but there is a max speed that the thing can go and it just cannot pass this speed. According to special relativity we can only travel just under the speed of light, it is the universes speed limit that cannot be overpassed (except of course light is able to reach the speed of light). Theoretically however, at the speed of light time would seem to stop!

So, now I think I owe you an explanation about light and it's ability to get away with going the speed of light without getting a ticket! This is because of the photon which really doesn't have mass meaning unlike you and me it does not need the unlimited supply of energy to reach such high speeds. It is important to understand that just because light can travel at such high speeds does not mean that it always does. It will only travel at the speed of light in a vacuum.  Maybe the most incredible thing to learn from this is that the light in the sky can really travel from place to place instantly since time has no impact, until it is no longer able to travel at the speed of light it is able to travel whenever and wherever it pleases without time being of any consideration.

Lets go back to the observer, if we put sent two people as lookout telling them to measure the time elapsed between an event, we would expect it to be the same. But if by chance the observers are at different distance from a gravitating mass the observer who is farthest from the place that the gravitational pull is emitted will experience a faster passage of time! So, yeah, physics is like a science fictional science, where we can literally time travel.

Websites Consulted:

http://www.einstein-online.info/elementary/specialRT/relativity_space_time

https://en.wikipedia.org/wiki/Gravitational_time_dilation

http://www.dummies.com/how-to/content/slowing-time-to-a-standstill-with-relativity.html

http://stream1.gifsoup.com/view6/2739769/bibbidi-bobbidi-boo-o.gif

http://www.physicsoftheuniverse.com/images/relativity_time_dilation.jpg
http://www.emc2-explained.info/Time-Dilation/#.Vj5FYq6rREI