Time Travel

I haven't posted anything in 20 days... I sure wish I could travel back in time and change that. Yah, I could change the date, but whatever.

Working on the pictures. Expect them in the future.

Time travel is one of the most enticing alleys for discovery for scientists: with good reason. It would mean being an observer in events past, for, what trumps learning history other than experiencing it? Who wouldn’t want to observe the space launches, the construction of Alexandria, the hoisting of Big Ben into its tower, the famous battles fought between the Greeks and Romans.

Sadly, this hasn't happened yet, and probably won't. This will discuss the path to time travel, the way it would work and does work.

So, first I’ll tell you what time travel is. It's quite a logical explanation, it's traveling through time. But to understand this, you must understand that time is as much a dimension as any other, it is the fourth dimension. You travel through it back and forth, but mostly the forth, as you travel through the three dimensions of space.

For example, right now, you are going forward in time. This may not be exceptionally amazing, but still, it's true. That's one way right there, move fast.

Light cones.
I tried to explain these in about three ways so far, which you won't see because I probably won't upload them, but here goes. What a light cone is is the light coming in from the past to you and the light going into the future from you. These are called past and future cones respectively.
The boundaries of the cone, that is to say the slope of the cone, is a constant determined by the speed of light in a vacuum, hence the name light cone.

Now, you are always traveling through the cones, and they always update to resolve for that, kind of like automatic updates for Microsoft but not nearly as annoying. The center where they meet is called the singularity. Just kidding, this isn't black holes. At least not yet. The center is the current moment in time for whatever is being represented.

You can travel into the future within the limits of the future cone. That is why the slope is the speed of light. You theoretically cannot travel faster than the speed of light. Now, in a 2D version of the cone, let's imagine a grid. In order to maintain my professionalism, I shall draw these out by hand.

Looking at the image, you can see three points in or on the future light cone. They all fall differently on the distance axis of X. The ones further away from the center line of stability means that the moment is further away in distance. Now, since the Y values of time are all the same, those that are further away require a faster speed to reach them at the same time. Since point 3 is twice as far away as point 1, you have to travel at twice the speed to reach the same spot at the same time.

Nothing can travel faster than light, so the boundaries of the cone are the universe preventing meltdown of the fundamental laws of nature. Slight exaggeration, that's just an ‘artist’s depiction’ of events.

These are the limits of time travel. This also means you can't go so fast you travel into the past. How'dya do this? Simple.

Exploit black holes. What do you mean we can't? Haven't humans exploited everything else? Why not black holes?

The way to possibly travel through time would be by exploiting their time bending properties. Black holes have the well known ability of bending light towards them, but also have a unique property of bending future and past cones till they reach a stasis. Of course, this has to happen when you are almost overlapping the singularity of the black hole. Can't the universe make anything easy?

A singularity, for the single variety of people with little to none knowledge of the stars, is an infinitely dense and infinitely small point at the center of a black hole. When you approach it, you can't escape. Nothing can escape. Not light, not sound (you're in space, no one hears your screams), not even Houdini. Simply put, it's the perfect prison if you don't expect to see your prisoner again.

The point is, if you can approach the black hole and go further you could essentially turn your cones 180° instead of 90°. This would mean you traveling into the future would travel you back in time. Great!

But no, this couldn't happen.

At least not yet, as we don't know how to a) go into a black hole and survive and b) how to go further in a black hole.

There's another way, incorporating the phenomenon known as time dilation. Time dilation is the thing that occurs to astronauts floating about in space in the wee hours of the morning at Antarctica and waving at the sleeping scientists while spacewalking. It's why they are slightly older than the people on earth.

Ever heard of it?

Probably not, it's quite obscure and as far as I know not taught as common core education. Time dilation is how objects age less the faster they travel. There's a whole formula dedicated to this:

t = t0/(1-v2/c2)1/2

In this, the t is time observed from other reference frame, the t0 is time in observer’s reference, the v is the speed of the object and c is the speed of light in a vacuum.

What does this mean? Well, time is a concept that is extremely relative: it varies on the observer (just like physics. Expect something on physics soon).

So, the t is the time from someone else's point of view and the t0 is the is the time from the point of view of the traveler. The speed is quite obvious, but here's to you spoon fed people. The speed v is how fast you travel. C? Oh, that's the speed of light in a vacuum.

This phenomenon is the reason clocks run faster in space and is an effect of the
Special Theory of Relativity.

Without getting into the detailed, specific, boring sciences of it, it basically states that an object will age less relative to another object if it travels faster than the relative object.


The speed of the object is shown as a percentage out of the speed of light here to make calculation much easier. An example would be if you plugged in .95 as your percentage for speed, with C staying 299,792,458 even though you can plug it in as (.95c)2 and cancel out the c’s. The observer time is 10 years. This gives:

t = 10/(1- (.95c)2/c2)1/2

t = 10/(1- .952)1/2

t = 10/ .312

t = 32 years


Yah, I pulled it off the website in the sources. If you protest I will change it.
Whatever.

Plugging it in gives a value of 32. This means that if an observer traveled for ten of his or her years at 95% of the speed of light, those around him on earth not traveling at that pace will have aged 32 years.

There is a trend in this data. The function itself is an exponential function. The slope becomes steeper the closer that your speed is to the speed of light. So, you age less the faster you move. For example, this image:

The apparent time dilation appears between the .3 and .4 percent marks of the speed of light.

Time dilation, however, requires you to travel ridiculously fast. This could probably be done soon but humans probably couldn't handle the speeds.

Ignore the obvious for now. This is a way to travel into the future. You can pair this with a method of hypothetical space travel to travel into the past.

What hypothetical method of space travel is there? There’s only one one could name: wormholes.

(Cue dramatic dun-dun-dun music)

Nah, wormholes are portals between two points in space held together by tons of energy. Not as exiting but much more useful. See what I did there?

Wormholes can be imagined by a simple exercise. Take a piece of paper and draw an A on one side of the paper and a B on the other. There are many ways to get from one side to another, but the quickest would be folding the paper in half to overlap the two points and then cut a hole through them. Unless you can teleport. If so sorry for wasting your time. Why don't you teleport into the past to avoid reading this.

Well, wormholes are what I said: a merger between two points in space to get to another place quicker. So, the issue that wormholes create is that they require extensive energy to hold up. Oh, they're theoretical. They were originally suggested by Albert Einstein and Nathan Rosen, and called Einstein-Rosen Bridges.

Say they can exist without collapsing immediately, they aren't at the currently predicted size of 10-33 centimeters, they are stable, and you don't die when you enter it, the wormhole would be able to transport people through connected space.

Now, I said extensive energy, but it's more like exotic matter. Think about it this way. If you have a bird garden and a new one opened up with more birds than you, to keep your business afloat, you need more exotic birds. In other words, more exotic (birds) matter, and hold your business up.

Don't confuse exotic matter with antimatter or dark matter. Exotic matter is matter that contains a negative density of energy and a large negative pressure. This type of matter has only been seen in the behaviours of certain vacuum states, and only exists as part of quantum field theory.

If a wormhole had enough of this exotic matter it would theoretically be able to transport humans. Of course the introduction of normal matter could lead to a collapse of the wormhole, but ignore that for now.

Remember we talked about time dilation? Well, pair it with wormholes! Say you manage to set up a wormhole. This is linked to a spacecraft. You set the spacecraft traveling at 95% of the speed of light for ten years. The wormhole would age ten years, but due to time dilation the other wormhole located on earth would age thirty-two years. Sweet, right?

Do you not get what it means? Well, if the scientist from earth travels through the wormhole without its obvious collapse, he would be effectively traveling into the past. He would be going back 12 years into the past as the wormhole would be linking two points in space-time not just space. This would mean that one could also go 12 years into the future if you go back through it.

Time travel has repercussions too, so it can't be taken lightly, but these are just the possibilities. It's not like they can be done right now, and it's not like they are all theoretically sound, but they could occur. The future is coming, and it demands the past.

For the first time in a while, going off of memory, some parts are based off of what I heard in professor Brian Cox’s Christmas lecture at the Institution “The Science of Doctor Who”.
http://hepweb.ucsd.edu/ph110b/110b_notes/node46.html
http://visualrelativity.com/LIGHTCONE/schwarzschild.html
https://www.quora.com/What-are-light-cones-of-an-event
http://www.phy.olemiss.edu/HEP/QuarkNet/time.html
http://www.space.com/20881-wormholes.html
http://www.space.com/21675-time-travel.html

Electric Cars

For those in touch with the auto world, electric cars are all the rage for development. Even those not directly interested in cars know about the energy friendly, environment caring cars that drive on electricity.

This topic surely isn’t as exciting as self driving cars, but the essence is more or less the same. Electric cars are meant to reduce hassle: they don’t emit greenhouse gases, don’t waste a expendable fuel source, and effectively lower our carbon footprint.

Electric cars are different from hybrid cars. Hybrid cars are those that use gasoline as a primary fuel source and use electric motors to improve efficiency. These just aren’t the same as electric cars, cars driven solely on electricity.

The image shown below is a comparison between electric and gasoline cars.

The major downfalls of electric cars are that they can’t drive for more than a hundred miles, and take a lot longer to recharge than gasoline-driven cars.

EV (electric vehicle) advocates claim that a hundred miles are already a decent amount, saying that the normal travels of most people rarely exceed the total.

As another counter to this statement, newer cars have mile ranges up to 200 miles. Even though the cost of the car goes up by increasing the range, the price of cents per mile will steadily go down: as battery prices are dropping.

Due to the fact that only thirty or so electric cars exist in the market currently, another issue is the lack of customer choice: but this is a hurdle that will soon be overcome by the market.

Demand for these cars are going up as well: as shown in figure 2, the projections for sales go up exponentially.

The main part to these cars is their battery. Electric cars have a rechargeable battery inside, that can be charged at home or at a dock. There are two parts to this: the type of battery and the type of charger.

According to the White House in a post, “The lack of affordable, highly functional batteries has been a particularly high barrier to the widespread adoption of electric vehicles.” Most agree with this statement, and development is under way for a better battery.

The precursor of modern car batteries came from Alessandro Volta in 1800. This was a container filled alternately with copper and zinc plates, separated by cardboard plates dipped in salt water. This battery ensured a steady flow of electrical current, by creating a chemical reaction, forcing the zinc plates, negative anodes, to release an electron for the copper disk, a positive cathode, to catch.

After two centuries, it is no wonder the battery hasn’t remained the same. With modern technology, the battery has been upgraded, but the basic principle has stayed the same. Now, batteries use lithium ions. The ion is shuttled back and forth from the anode and cathode, and is called a lithium ion battery.

The lithium ion battery provides a higher energy density than previous batteries. Compared with the nickel-metal hydride battery used in the Toyota Prius, for example, a lithium-ion battery of the same weight and volume would increase energy density two to three times, says Dr. Srinivasan.

Dr. Venkat Srinivasan is the manager of the Battery for Automotive Transportation Technologies Program, an Energy Department-supported program managed by Lawrence Berkeley National Laboratory at the University of California, Berkeley.

Jeffrey P. Chamberlain, head of the Electrochemical Energy Storage group at the Argonne National Laboratory, a lab near Chicago sponsored by the Energy Department, says that all vehicles available with electricity as a primary power source use some form of lithium-ion battery, and that these types of battery will be prevalent for at least the next two decades.

Researchers are experimenting with bonding lithium with other materials in the battery cathode. The materials used dictate the voltage and amount of lithium the cell can hold, and as both increase so does the energy efficiency for the overall cell, according to Dr. Srinivasan.

At Argonne National Laboratory, people are working with newer mixes of nickel, manganese, and cobalt for the cathode, as blending in different amounts and forming different structures has shown to double the efficiency, and, in turn, Argonne is offering patents for the material to various battery makers. According to Mr. Chamberlain, the result would be batteries “that squeeze more energy into a smaller package, are less expensive to make and last longer.”

Similar to changing the cathode, researchers at Argonne and other places are contemplating swapping the cathode for silicon, replacing the current carbon anode, as silicon will theoretically increase the amount of energy holdable tenfold.

This was as of 2011, and even as recently as 2015, these batteries have major limitations: scientists haven’t found an efficient way to get over the expanding properties of silicon: it can expand up to 300%.

According to Mr Chamberlain, to get over this hurdle, researchers are experimenting with blending silicon with other materials like graphite to try to find a balance to prevent expansion while increasing energy density.

These batteries, or rather, electric car batteries are the most expensive part of a car, easily racking up into the thousands. Due to this, manufacturers deem it competitive information: but, according to a study by the Frankfurt School of Finance & Management, the prices for batteries have gone down by about 35% between 2014 and 15.

Looking at the graph (figure 3) the decrease in price is drastic.

According to a study by McKinsey & Company, “Despite that drop, battery costs continue to make EVs more costly than comparable ICE-powered variants. Current projections put EV battery pack prices below $190/kWh by the end of the decade, and suggest the potential for pack prices to fall below $100/kWh by 2030.”

The drop in mention is battery costs falling from ~1,000 per kWh in 2010 to ~$227 per kWh in 2016, according to McKinsey.

Basically, McKinsey doesn’t expect a real drop in prices, or at least no ~$100 per kWh battery to occur soon, even though Tesla has hinted at this possibility.

Now, these prices mentioned are for the entire package: both the battery pack and cells.

Batteries must also be charged for the car to actually drive. The battery is charged differently than most expect: the port is actually on the car itself. The appliance known as a ‘charger’ is in reality just a converter for AC to DC, allowing your electricity to feed a car. Its real name is an Electric Vehicle Service Equipment, or an EVSE, and all EV owners should own one. Like, seriously.

A general consensus between EV drivers is that chargers cost around 6-7 hundred dollars. Each EVSE can handle a specific amount of amps. The suggested amperage is 30, allowing approximately 30 miles from an hour of charge. This is like 15 amps will charge about 15 miles in an hour. There are two things to note from this, however, that 30 amp EVSEs need a circuit breaker of at least 40 amps, and that not all EVs will benefit from the faster charge, notable ones including the Nissan LEAF before the 2013 model.

It is essential that chargers are mobile, or rather movable, so that if needed, the car can be charged from somewhere else, as it decreases the cost of buying another one. The car should ideally be reached by the charger with some length of cord left over as well.

Most cords are at lengths of 15 to 25 feet in length, and increasing the amount of wire will also increase the cost.

Despite some minor setbacks, EVs have proven to be developing fast: they may be the tech breaking dependence ties on fossil fuels. They will continue to develop, and till then, the world will wait.

References used in the making of this article:

http://www.plugincars.com/ basic info, the various guides give great info.

http://www.nytimes.com/2011/03/31/business/energy-environment/31BATTERIES.html On lithium ion batteries

http://newatlas.com/silicon-anode-performance-batteries/40058/

http://www.greencarreports.com/news/1108199_how-much-have-electric-car-battery-costs-fallen-this-much

https://electrek.co/2017/01/30/electric-vehicle-battery-cost-dropped-80-6-years-227kwh-tesla-190kwh/

Figure 1: http://www.plugincars.com/electric-cars

Figure 2: http://www.plugincars.com/guide-electric-vehicles-and-the-smart-grid.html

Figure 3: http://static4.businessinsider.com/image/588287f4ee14b62b008b92d8-1200/20170120batteryprice.png