Relativity is one of the best famous scientific theories of the 20th century, but how well does it clarify the things we see in our daily lives?

Formulated by Albert Einstein in 1905, the theory of relativity is the idea that the laws of physics are the similar in all places. The theory clarifies the behaviour of objects in space and time, and it can be used to forecast everything from the presence of black holes, to light bending due to gravity, to the behaviour of the planet Mercury in its trajectory.

The theory is deceptively easy to understand. First, there is no "absolute" frame of reference. Every time you calculate an object's velocity, or its momentum, or how it experiences time, it's always in relation to something else. Second, the velocity of light is the similar no matter who calculate it or how fast the person calculating it is going. Third, nonentity can go quicker than light.

The implications of Einstein's most famous theory are deep. If the speed of light is always the same, it means that a cosmonaut going very fast comparative to the Earth will amount the seconds ticking by slower than an earthbound spectator will — time fundamentally slows down for the cosmonaut, an occurrence called “Time Dilation”.

Any object in a big gravity field is rushing, so it will also practice time dilation. Meanwhile, the cosmonaut's spaceship will undergo length contraction, which says that if you took an image of the spacecraft as it flew by, it would look as though it were "squished" in the direction of motion. To the cosmonaut on board, though, all would seem normal. In addition, the mass of the spaceship would seem to rise from the point of view of people on Earth.

But you don't essentially need a spaceship accelerating at near the speed of light to see relativistic effects. Actually, there are numerous examples of relativity that we can see in our daily lives, and even technologies we use at present that prove that Einstein was right. Here are some ways we see relativity in action.

## 1. Global Positioning System

In order for your car's GPS navigation to operate as precisely as it does, satellites have to take relativistic effects into account. This is for the reason that even though satellites are not moving at anything near the speed of light, they are still going very fast. The satellites are also transmitting signals to ground stations on Earth. These stations (and the GPS unit in your car) are all undergoing higher accelerations due to gravity than the satellites in orbit.

To get that pinpoint precision, the satellites use clocks that are exact to a few billionths of a second (nanoseconds). As each satellite is 12,600 miles (20,300 kilometres) above Earth and moves at about 6,000 miles per hour (10,000 km/h), there's a relativistic time dilation that tacks on about 4 microseconds each day. Add in the influence of gravity and the number goes up to approximately 7 microseconds. That's 7,000 nanoseconds.

The difference is very real: if no relativistic effects were taken care for, a GPS unit that shows you it's a half mile (0.8 km) to the next gas station would be 5 miles (8 km) off after only one day.

## 2. Electromagnets

Magnetism is a relativistic effect, and if you utilize electricity you can thank relativity for the truth that generators work at all. If you take a loop of wire and move it over a magnetic field, you produce an electric current. The charged particles in the wire are influenced by the altering magnetic field, which forces some of them to move and generates the current.
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But now, picture the wire at rest and visualize the magnet is mobile. In this case, the charged particles in the wire (the electrons and protons) aren't moving now, so the magnetic field shouldn't be influencing them. But it does, and a current still flows. This displays that there is no fortunate frame of reference.

Thomas Moore, a professor of physics at Pomona College in Claremont, California, utilizes the principle of relativity to show why Faraday's Law, which says that an altering magnetic field generates an electric current, is true.

"Since this is the fundamental principle behindhand transformers and electric generators, anyone who uses electricity is undergoing the effects of relativity," Moore said.

Electromagnets work through relativity as well. When a direct current (DC) of electric charge runs through a wire, electrons are moving through the material. Normally the wire would appear electrically neutral, with no overall positive or negative charge. That's a result of having approximately the same number of protons (positive charges) and electrons (negative charges). But, if you put additional wire next to it with a DC current, the wires attract or repel each other, subject to the direction the current is flowing.

Supposing the currents are flowing in the same direction, the electrons in the first wire perceive the electrons in the second wire as motionless. (This undertakes the currents are about the same strength). In the meantime, from the electrons' viewpoint, the protons in both wires appear like they are moving. Because of the relativistic length contraction, they seem to be more closely spaced, so there's more positive charge per length of wire than negative charge. Since like charges repel, the two wires also repel.

Currents in the conflicting directions product in attraction, as from the first wire's point of view, the electrons in the other wire are more packed together, generating a net negative charge. In the meantime, the protons in the first wire are generating a net positive charge, and opposite charges attract.

## 3. Gold's Yellow Colour:

Most metals are shiny for the reason that the electrons in the atoms jump from dissimilar energy levels, or "orbitals." Some photons that strike the metal get captured and re-emitted, however at a longer wavelength. Most visible light, however, just gets reflected.

Gold is a heavy atom, so the inner electrons are moving fast sufficiently that the relativistic mass increase is significant, as well as the length contraction. As a consequence, the electrons are spinning about the nucleus in shorter paths, with more momentum. Electrons in the internal orbitals carry energy that is approximately close to the energy of outer electrons, and the wavelengths that get absorbed and reflected are longer.

Longer wavelengths of light mean that some of the visible light that would typically just be reflected gets absorbed and that light is in the blue end of the spectrum. White light is a combination of all the colours of the rainbow, but in gold's situation, when light gets absorbed and re emitted the wavelengths are generally longer. That means the mixture of light waves we see inclines to have less blue and violet in it. This makes gold look yellowish in colour since yellow, orange and red light is a longer wavelength than blue.

## 4. Gold Doesn't Corrode Easily:

The relativistic effect on gold's electrons is also one cause that the metal doesn't rust or react with anything else simply.

Gold has only one electron in its valence shell, but it still is not as reactive as calcium or lithium. In its place, the electrons in gold, being "heavier" than they should be, are all held near to the atomic nucleus. This means that the furthest electron isn't probable to be in a place where it can react with anything at all — it's just as likely to be amongst its fellow electrons that are near to the nucleus.

## 5. Mercury Is a Liquid:

Just like gold, mercury is also a heavy atom, with electrons seized close to the nucleus because of their speed and resulting mass increase. With mercury, the bonds among its atoms are weak, so mercury melts at lower temperatures and is normally a liquid when we see it.

Just a few years ago almost all televisions and monitors required cathode ray tube for display. A cathode ray tube works by shooting electrons at a phosphor surface with a big magnet. Each electron makes a lighted pixel when it hits the back of the screen. The electrons fired out to produce the picture move at up to 30 percent the speed of light. Relativistic effects are obvious, and when manufacturers designed the magnets, they had to take care of those effects.

## 7. Light:

If Isaac Newton had been right in supposing that there is an absolute rest frame, we would have to come up with a different clarification for light, as it wouldn't happen at all.

"Not only would magnetism not be real but light would also not exist, as relativity needs those changes in an electromagnetic field move at a finite speed instead of instantaneously," Moore, of Pomona College, said. "If relativity did not impose this condition … changes in electric fields would be communicated instantaneously … instead of through electromagnetic waves, and both magnetism and light would be needless."

## 8. Nuclear Plants and Supernovas:

Relativity is one cause that mass and energy can be transformed into each other, which is how nuclear power plants operate, and why the sun shines. Another significant effect is in supernova blasts, which signal the death of enormous stars.

"Supernovas occur as relativistic effects overcome quantum effects in the core of a sufficiently huge star, allowing it to abruptly collapse under its own weight until it turn into a much smaller and harder neutron star," Moore said.

In a supernova, the external layers of a star downfall onto the core, and produce an enormous explosion that, among other things, produces elements heavier than iron. Actually, approximately all the heavy elements we know off are produced in supernovas.

"We are made of stuff produced in and dispersed by supernovas," Moore said. "If relativity did not exist, even the most enormous stars would finish their lives as white dwarfs, never exploding, and we would not be around to think about it."