Space Web

Getting to Know the theory of relativity

As we grew up, learned to walk, scanning items and learn to perceive the world around us, we created natural notions of space and time in our heads. When you set prior to running the handwatch by kitchen clock, after returning home they tend to show the same time as a kitchen clock. If not, we assume that some clocks went wrong. When traveling by car, and we look out the window,we do not notice any changes - houses are unchanged shape and everything looks the same as when standing still. If you want to come to school more quickly, you'll walk faster. If we want to get there in half the time, twice the speed. All these ideas are run due to the fact that in our lives not encounter to high speeds. We are walking, driving a car, flying my plane, but always a rate much less than the speed of light, which is unimaginable 300,000 kilometers per second. It takes eight minutes for the light from sun to arrive to the Earth. Albert Einstein figured out that at nearly the speed of light our innate intuition fails and incredible things happen. Houses begin to change shape, clocks slowdown, shorten the distance and, as we will explain in detail, it may also happen that after a person is on a far trip and comes back, he can be thirty years younger than his identical twin.

Magic Speed of light

Already medieval sages struggled with the challenge to measure the speed of light , it was a tough one. Since the times of lanterns from remote mirrors were fruitless and reasonable value provided to sophisticated methods, such as for example observing Jupiter Io. Astronomer Ole Rømer noticed that the moon Io is based on the shadow of Jupiter with some delay when Jupiter is farther from the Earth. This can be explained only by the light if it takes a long time until it reaches the earth. Accordingly, the estimated speed of light 220,000 km per second. Later he managed to make ingenious experiments on a rapidly rotating mirrors or using optical laws.

When starting moon Io, light takes some time before it gets to Earth. When Jupiter is farther from the Earth, the time is longer. The actual speed of light, however, was not as interesting as the magical property which amazed scientists and it took therir breath away.

Isaac Newton hypothesized that light spreads ether to be a kind of matter which is all around us. He wrote: I do not know what the ether, but if it is made of particles, it must be smaller than those that make up the air or light ... Some scientists believed that light spreads ether like the sound travels by air and searching for analogies. The sound is caused by the oscillation of air molecules, which in themselves are finding it progressively until unbranched vibrate our eardrum. Thus, the speed of sound depends on the impact velocity of air molecules. Similarly, should determine the speed of light remains unknown ether. No one knew what might constitute ether and how to find it. They used more sensitive optical apparatus capable of even a small measure the change in the speed of light. The same went anywhere on Earth in any direction.

Thus, the hypothetical ether is not relative to the Earth's moves, but it rotates with it. If the ether is moving, we measured the differences in the speed of light, as light spreads in ether.But here begins a logical problem, because ether is not only on earth, but it must be filled with the entire universe, to be able us to see the stars shine. Last resort ether was far-fetched idea that the earth is entrained ether with it.

The idea of moving the ether along with the earth and ether standing nearby stars have led to the result that the sky should have different colors in different directions, as indicated by the laws of optics. But we don't see this, because the whole sky is blue. The idea of ether led to even many more disputes, for instance the fact that the light has certain properties which the sound is allowed (e.g., the ability of polarization).The last nail in the coffin of ether hammered James Clerk Max well, when built a final theory describing light. He came to the conclusion that the light travels in a vacuum invariant speed of 300,000 kilometers per second.

Time passes slowly

The most accurate atomic clocks were loaded on a plane and went around the Earth. When the aircraft returned, the flying clocks were showing a different time and were compared to terrestrial atomic clocks actually "younger". This hacks our traditional notion of time, which should run the same everywhere. Another interesting phenomenon is the so-called secondary cosmic rays hitting the Earth's surface. Cosmic rays hitting the Earth's atmosphere about thirty kilometers above the ground gives rise to a particle - muon. These particles are living so short (two microseconds) that, according to classical ideas have no chance of thirty kilometers and reaching the Earth's surface. Yet we detect them on earth. The explanation is that, in our view, muons are living longer, because thanks to their move time passes slower for them. For this extended time they manage to hit the ground.

The various old twins

Reflections of a slower passage of time will lead to a surprising conclusion and the most interesting is the paradox of twins. Danka and Janka are identical twins. They are the same age and they are recognized by their own mother only. Danka is one day away, and embarks on a long journey quick and spacecraft returns to Earth. Janka pending on Earth pulls her calendar 40 years, but Danka only 10 years old, because from the perspective of Janka with Danka's time in the rocket passes slowly. Danka is suddenly 30 years younger than Janka, although born together. Although this phenomenon is named as paradox is real and there is no paradox in itJust interesting to note the gaps in our understanding of time. A similar experiment was successfully carried out with the hours mentioned above.

Distances are reduced

The sci-fi movies like Star Wars or Star Trek spacecraft overcome long distances in a short time. The films were inspired by the theory of relativity and the fact is that large distances do not need a long time to overcome. At high speeds, the distance of the two stars shortened to almost zero! Imagine that you would want to reach distant planet in a rapid spacecraft. Gradually rise planet is gradually approaching. At the near-light speed something unexpected happens. You didn't even go a few kilometers and the distance to the planet is so short. You look out the window and all the stars are stuck close to each other and the planets are flattened as a pancake. All distances are shortened in the direction of movement. You think it is a dream, you get scarred, and you start slownig down. Suddenly, everything starts to move away from each other and enter into the original dimensions. The planet, which a while ago was near to you is again very far. You should be aware of what Galileo Galilei said.Because in space we do not have a fixed point, we can not tell what is actually moving. It moves the missile or the star? After the muon moves himself to the earth or the earth to it? Answer thread from the observer. The observer sees the rocket that is around stars and planets, and therefore shortening the distance between them. An observer on the Earth sees the moving hand the rocket that is reduced in the direction of movement. They do not see, however, that the missile got closer to the planet. Everyone just sees something else.

Enchanted phone

Lets bring the consequences of FTL to the extreme, we will describe a fictitious invention named Tachyon phone now. Tachyons are hypothetical particles that move faster than light, so even if there are, nobody will ever see them. If tachyons exist, we could construct the phone, where instead of electrons flowed cable Tachyon. Scientists have calculated that this phone would be very strange properties. If Janko would call with this telephone to Danka "How are you?" And Danka answer "Great!" Janka receive a response before to ask! The phenomenon of consequence overtake cause (in our examples overtake answer a question or ball comes out rather than fit), we call it disruption of causality. To be utterly phone and avoid a similar scenario, we believe the claim that disruption of causality should not happen and nothing can move faster than light. Then, according to the calculations in special relativity everything right. The speed of light has thus become more magic. Not only is it all respects the same, but even the maximum possible rate at which information can be disseminated.