Randeria, 10th - Cypress, TX
You ramp up the throttle as far as it goes and your sleek, shiny spacecraft gains speed. The speedometer becomes a blur of numbers as your ship accelerates. You're pressed into your seat as the g-forces increase exponentially. A special dial switches on that indicates the percent speed of light you are traveling. It climbs from 1% to 20%, then to 50% as your warp engines start warming up. Your craft, "Faster Than Light" (aka FTL), is a state-beyond-the-art spaceship designed to travel faster than light (hence its name). With a roar that you feel in your bones, the warp engines reach full power and the planets, stars, and suns blur by you as you reach and pass the speed of light. Wait a minute, is this really possible?
Isaac Newton was the first to mathematically define gravity as a force between two objects in the empty backdrop of space, which goes on to infinity. A patent office secretary in Germany thought otherwise, and came up with another theory of the universe: General Relativity.
General relativity, along with revolutionizing science and redefining our world, is a theory of gravity, created by the famous physicist Albert Einstein (yes, the one with the crazy hair). In his theory, he concluded two things:
- Time is not constant; it is a dimension, along with height, length, and width, and therefore subject to manipulation. This is called space-time, and makes up the universe.
- Mass is directly proportional to velocity. Meaning, the faster you go, the heavier (denser) you get, and vice versa. This is a MASSIVE idea.
With these in mind, we can start to simplify General Relativity.
Imagine a large blanket, and drop a bowling ball on it. The bowling ball causes a dip in the blanket, and anything that is lighter than the bowling ball will make a smaller dip and roll towards the bowling ball, where it will make a bigger dip. This is analogous to the real world, where the blanket is space-time and the bowling ball is a massive star. The dent (which would be 3D) is gravity, which Einstein argues is just a warping of space-time. Since gravity can bend space-time, and space-time is made up of three spacial dimensions and a fourth dimension time, gravity can bend time. Wait, what? How can that be possible? If gravity can bend time, does that mean that time goes slower near a large object? Yes. It does. In fact, it has actually been proven! Global Positioning Satellites (GPS) today use this effect to pinpoint your location accurately (otherwise they'd be miles off track and you might find yourself very lost).
Einstein has proven that time is relative. Meaning, not only can it bend, but different people experience it differently! In fact, there is another analogy to illustrate this. Say you and your friend are on rockets, and you are traveling faster than your friend. You will find that your watch actually goes slower than your friend's, and that the time difference depends on how fast you are traveling relative to the same object. Yes, relative to the same object. Depending on what you are measuring against, your speed can change.
There's another analogy for this. Say that you are on a train, and you are tossing a ball up and down. To you, that ball would go up and down, while to someone outside the train, the tossing of the ball would trace a wave-like shape. To a person in the train, the world outside is moving, whereas to an observer, the train would be moving.
Going back to our rocket analogy, there's one more thing to be made clear. Why is time slower for the faster one? This is where Einstein's second conclusion, that mass is directly proportional to velocity, comes in. As you go faster, your mass increases, and you bend space-time a little bit more. You would have to be traveling extremely fast, near the speed of light to see this effect, though.
While we're on the topic of light, let me explain one of the most famous things general relativity disproved; faster than light travel (FTL). It is known that FTL is not possible, but why is it so? We saw that as you go faster, your mass increases. Let's assume that you carry energy (fuel) with you. Since you need more energy to propel more mass, your starting mass increases. Since your starting mass increases, your final mass increases too. This will never end. Even if you were externally powered, meaning that you get energy without changing your mass, there is not enough energy in the universe to propel you, and you would end up having infinite mass. Say you had no mass in the first place, though? Could you achieve FTL travel? Well, then you would be light. Light has no mass, and since it can only go at a finite speed, that speed will be the speed limit of the universe; the speed of light in a vacuum, (approximately 3.00 * 10^8 meters per second) more commonly called . Therefore, a scientifically accurate FTL story would end differently.
With a roar that you feel in your bones, the warp engines tune to full power, and you feel a burst of acceleration - that quickly goes away. Confused, you look at the speedometer, see it stop, and then reverse! As you slow down to less than 0.005% the speed of light, you feel like you get lighter. You look at the fuel levels, and see that you have no fuel. Panicked, you look around you, and see nothing. You must have gone beyond the edge of the Milky Way, and, with no fuel, have no hopes of going back. You knew this would happen, because of general relativity, but you decided it was a risk to take. Now here you are. Floating through space-time, sitting in your seat, all alone, doomed to stay till you grow old and die, with no hope left to see any life again, and the vast inky blacker than black darkness of space stretching out in front of you.
Students 6th-12th Grades