This is kind of a rare post. I never really make report-type blog posts about educational stuff, but I happen to find this subject very fascinating.
Everyone in elementary school learns that the sides of a triangle always add up to 180 degrees. However, in the last century, people realized that other forms of geometry were possible. If you made a vertical line from the north pole to the equator, the equator being the bottom line of your triangle, and then made a line back to the north pole, you'd have a triangle with three right angles.
Congratulations. You broke science.
This type of geometry is called Non-Euclidean geometry.
It may sound shmancy, but you already know what normal Euclidean geometry is.
That's it. Euclidean geometry is when you draw shapes on a flat plane.
Just like how you can make a triple-right-angled triangle on a curved surface, many people believe that time can be manipulated in curved space as well.
Here's a poem that explains how to time travel:
There was a young lady of Wight,
Who traveled much faster than light,
She departed one day,
In a relative way,
And arrived on the previous night.
So that's the answer, right? If we build a space-ship that can travel faster than the speed of light we can go anywhere in time, right?
Er, no.
Unfortunately it would take an infinite amount of energy for a spaceship to travel faster than the speed of light. So basically if you're from our generation, and want to go to a Pink Floyd concert, too freaking bad for you.
But don't worry. Einstien's got this. He stated once in a paper that the effects of gravity could be described, by supposing that space-time was warped or distorted by the matter and energy in it. We can actually see this "warping" of space-time produced by the mass of the Sun, in the slight bending of light or radio waves, passing close to it. The bendiness of the radio waves is only a thousandth of a degree, but it's still pretty cool, right?
Seriously, this subject fascinates me so much. If you don't like this post, screw you.
Back to le topic ._.
Anyways, when radio waves act all bendy-like near large objects in space, that only supports the theory of general relativity. Not surprisingly, the amount of bendy warping stuff happening in our solar system is barely anything at all, considering the fact that the gravitational fields are all pretty weak. However, we know that very strong gravitational fields can exist, for example in the Big Bang, or Black Holes.
On another note, there was this smart science dude named Kurt Goedel, and he found a solution of the field equations of General Relativity, which basically means a universe in which all the matter is rotating. In this universe, it was possible to set out in a space ship and arrive before you left. Turns out Kurt Goedel went to the same college as Einstein, and enjoyed derping around by disproving simple things such as arithmetic in shmancy smart-like ways. Also, the fact that Kurt contributed to the fact that time travel was possible, kind of pissed off Einstein, who thought time-travel wasn't possible. One does not simply piss off Einstien.
We now know that Kurt's model of a universe couldn't represent ours, because his model wasn't an expanding one.
However, there are more reasonable solutions allowing time travel that have recently been
discovered.
One of the solutions involves these things called Cosmic Strings that formed after the Big Bang. Science Fiction writers don't know about them yet, so you are an unintentional hipster at the moment. You're welcome.
Anyways, one of the more plausible theories of a universe that will allow time travel involves the Cosmic Strings. They're a form of "theoretical physics." Cosmic Strings are strings under enormous tension (like, we're talking 100 billion billion tons). A Cosmic String attached to our Sun would make it go 0 to 60 in a 30th of a second.
Both Kurt's theory, and the Cosmic String theory have a common factor. Time is definitely warped, because it's curved, making time travel a possible scenario.
Great! Now that we have all this information we can totally just become time lords and travel around in the Tardis now. . . right?
Um, I have bad news.
If someone made a research grant application for time travel, it would probably be dismissed immediately. No government agency could afford being seen spending public money on something theoretical such as time travel.
Closely connected to time travel is the ability to travel from one part of the galaxy to another in a reasonable amount of time. To do that, we'd need a wormhole. If instead you wanted to travel back in time through a wormhole, the ends would have to be moving relative to each other.
To create a wormhole, one would need to warp space time in the opposite way, to that in which normal matter warps it. Ordinary matter curves space time back on itself, like the surface of the Earth. So now we just reverse it! It's totally simple deep-space science involving negative mass, and negative energy density. A third grader could figure it out. Really.
Crap, I'm letting my sarcasm take over this post too. Dear lawdy this is getting out of hand.
Anyways, this negative energy density stuff is called Quantum Theory. Maybe you've heard of the similar phrase, Quantum Physics? Yes? No? Okay. Quantum Theory basically allows energy density to be negative in some places, just as long as it's positive in others :D I'm not gonna explain how Quantum Theory concerns your life in the least because I honestly don't know.
Yay! Now we have experimental evidence from Quantum Theory, and the bending of light, that space-time is in fact curved (like the non-Euclidean geometry I showed in the beginning), and we can in fact warp it in a negative direction.
But my question is, if we soon find out the secret to time travel in the future, why haven't any "future tourists" visited us in our time and told us awesome stuff about their cool technology and lives?
Or maybe they have been coming all along! They're just not allowed to act like they're from the future and they have to blend in to prevent people from freaking out.
I'm going to log off now.
