The universe itself provides a barrier in the speed of any object, making it impossible to travel indefinitely fast. This barrier is the speed of light, measuring in at approximately 870,000 mach (1 mach is the speed of sound). Traveling at high speeds requires a lot of energy, and when trying to accelerate to the speed of light, the energy needed becomes exponentially large, approaching infinity at the speed barrier.
However, there is a seemingly obvious way to make light itself travel faster than the speed of light. All that is needed is a moving vehicle and a laser or other light-emitting object. Just place the laser on the moving vehicle in the direction of motion and the beam will move faster than it normally would. Once the speed limit is broken, most of current physics would fall apart.
Then, in 1903, Albert Einstein provided a solution to this problem, that he called "special relativity". Einstein claimed that every observer, no matter how fast they are traveling, always sees light as traveling its usual speed, and that space and time are relative; meaning that objects' motion in space and time can only be measured relative to other objects.
Another main point of the theory of relativity is that space and time are linked into one continuum called space-time. Objects with mass bend space-time, with more massive objects bending it more than lighter objects. A black hole, the super-dense core remnant of a massive star, creates a gravity well so large that not even light can escape its gravity. This is why it appears to be black; no light is emitted from the black hole itself and is only absorbed into it.
These "relatively" basic laws will lead to some interesting consequences. For example, the faster that an object is traveling, the slower time moves for that object. The commonly known Twin Paradox puts this concept to use, describing two identical twins and a light-speed spacecraft. When one twin travels on an interstellar trip, he might age weeks while his brother back on Earth ages decades. This concept is called time dilation. A related concept called length contraction is the shortening of appeared length in near-light-speed travel. For example, the twin on the ship will only age weeks because he sees the distance ahead of him as mere light-weeks rather than dozens of light-years due to length contraction.
However, there is a seemingly obvious way to make light itself travel faster than the speed of light. All that is needed is a moving vehicle and a laser or other light-emitting object. Just place the laser on the moving vehicle in the direction of motion and the beam will move faster than it normally would. Once the speed limit is broken, most of current physics would fall apart.
Then, in 1903, Albert Einstein provided a solution to this problem, that he called "special relativity". Einstein claimed that every observer, no matter how fast they are traveling, always sees light as traveling its usual speed, and that space and time are relative; meaning that objects' motion in space and time can only be measured relative to other objects.
Another main point of the theory of relativity is that space and time are linked into one continuum called space-time. Objects with mass bend space-time, with more massive objects bending it more than lighter objects. A black hole, the super-dense core remnant of a massive star, creates a gravity well so large that not even light can escape its gravity. This is why it appears to be black; no light is emitted from the black hole itself and is only absorbed into it.
These "relatively" basic laws will lead to some interesting consequences. For example, the faster that an object is traveling, the slower time moves for that object. The commonly known Twin Paradox puts this concept to use, describing two identical twins and a light-speed spacecraft. When one twin travels on an interstellar trip, he might age weeks while his brother back on Earth ages decades. This concept is called time dilation. A related concept called length contraction is the shortening of appeared length in near-light-speed travel. For example, the twin on the ship will only age weeks because he sees the distance ahead of him as mere light-weeks rather than dozens of light-years due to length contraction.
Even at relativistic speeds, just a flight to the nearest star will take over four years with the current understanding of physics. However, a solution has been put forth involving the curvature of space-time.
The so-called Alcubierre warp drive proposes to expand space behind a spaceship and contract it in front of the spaceship, effectively creating a space-time bubble that could travel indefinitely fast. The way that this works is that the spaceship is not actually moving faster than light; the space around it is. As shown in the diagram to the left, a spacecraft would move forward into its own gravity well, like a cat chasing its own tail.
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