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why can light travel so fast

why can light travel so fast插图

Electromagnetic wave
But have you ever wondered why light travels so fast?One reason light travels so fast is because it is anelectromagnetic wave. This means that it is made up of electric and magnetic fields that oscillate at right angles to each other.

Why does light always take the shortest path?

Does light always take the shortest path? Fermat’s principle states that of all the possible paths the light might take, that satisfy those boundary conditions, light takes the path which requires the shortest time. Who was the first to observe light travel in a straight line and always takes shortest path?

Why does light have an universal speed limit?

The speed of light is the upper limit for the speeds of objects with positive rest mass, and individual photons cannot travel faster than the speed of light. This is experimentally established in many tests of relativistic energy and momentum.

Why is it not possible to travel faster than light?

If an object tries to travel 186,000 miles per second, its mass becomes infinite, and so does the energy required to move it. For this reason, no normal object can travel as fast or faster than the speed of light. That answers our question, but let’s have a little fun and modify the question slightly.

Why light travels faster than sound?

Light travels faster than sound because sound waves can only travel as waves of pressure in a medium, whereas electromagnetic waves, of which light is made, move on their own even through vacuum. Light’s speed decreases a little when it goes through various mediums, as electromagnetic waves interact with the medium at a subatomic level. Sound’s speed depends on the medium through which it travels.

What is light?

Light is an electromagnetic wave, a disturbance in electric and magnetic fields. Light can be broken up into different types, and the combination of all these packages is the electromagnetic spectrum. It also can be created by making an electron oscillate. This creates an oscillating magnetic field, and an oscillating electric field is an electromagnetic wave or light.

Why does light travel so fast?

Light waves travel in straight lines through the air. These lines are called rays. If light travels in a straight line, what happens when it hits an object in its path? Well, light cannot bend to go around something. The light rays are either reflected, absorbed, or refracted. The reflected light helps us to see objects.

Why do we use the letter C in the speed limit?

The other prediction that supports a speed limit is that inertia increases as velocity approaches the speed of light . It means mass increases. So mass is a speed impediment, and nothing with mass can reach the speed of light. But if anything is massless, it can only go the speed of light because there’s no mass to impede the speed. For example, photons are massless particles. Particles must travel at the speed of light, and since they are traveling at the speed of light for them, time stands still.

What is Einstein’s theory of relativity?

Einstein’s theory of relativity describes space and time as a smooth fabric distorted or bent by massive objects. It’s been a spectacularly successful explanation of gravity and the large-scale behavior of the universe. Whereas quantum mechanics, another spectacularly successful model, describes the workings of atoms, subatomic particles, and some of the fundamental forces of nature. But scientists have never been able to reconcile the two.

Why do they use the letter C?

Causality is the reason why they use the letter C to describe the speed of light in equations. The other prediction that supports a speed limit is that inertia increases as velocity approaches the speed of light. It means mass increases. So mass is a speed impediment, and nothing with mass can reach the speed of light.

How fast does a light wave travel?

Thus while a light wave travels at a speed of 300,000 kilometers per second through a vacuum or the gaps between atoms, the absorption and re-emission process in different materials results in the net speed of the light wave being less than the speed of light.

Why would it take infinite energy to make matter?

Time and space wouldn’t exist because all things communicate with each other instantly. It would always be forever here and now. But if the speed of light were slower , that might be even cooler because scientists would be able to see back to the Big Bang. The speed of light, of course, is just one of many constants in the universe like gravity, the specific charges, weights of the different fundamental particles.

Why does light look blue?

If your eye looks at fields which are wiggling about twice that fast, or about 1,000,000,000,000,000 every second, the light looks blue. All of the colors of the rainbow are due to the fields wiggling at slightly different rates. Visible light is not the only phenomenon due to wiggling electric and magnetic fields.

What do physicists have drawn from this result?

The conclusion that physicists have drawn from this result is that light consists of waves of electric and magnetic fields. This is a fascinating result: that we learn something about light by studying magnets and electrical currents. You may wonder why we can’t see the waviness of light.

What is the difference between an electric field and a magnetic field?

What that means is that it is an oscillating electric and magnetic field. An electric field, is what causes the attraction between a positive and a negative charge. A magnetic field cause the attraction between the North and South poles of a magnet. In light, the strength of these fields changes with time and place.

Do waves travel at the same speed?

It doesn’t matter how rapidly the fields wiggle back and forth, they will always travel at the same speed. (In air, the waves go ever so slightly slower than in vacuum, and in glass, they can go only about two-thirds as fast as they would in vacuum, but this is not important right now.

Is radio the same as visible light?

This is nowhere near as fast as the wiggling in visible light. But radio waves and visible light are very similar - they are both waves of electric and magnetic fields, which just happen to be wiggling at different rates. Therefore, they both travel at the speed of light.

What is the Speed of Light Relative to Me If I Am Travelling at the Speed of Light?

If I am travelling at the speed of light, what is the speed of light relative to me? The answer depends on what you consider a’speed’ to be. Using a scale, we can work out the relative speed of an object and an airplane. The distance between a plane and an airplane is measured in miles per second, but the plane’s distance from the ground is measured in kilometers per second.

What Would the Universe Be Like If the Speed of Light Were Infinite?

An infinite speed of light would negate Einstein’s theory of relativity. It will take an object an infinite amount of energy to move through space at any speed. There is no way an object could travel faster than the speed of the light, but an endlessly slow object might make interesting observations. Fortunately, the speed of light is only a fraction of the universe’s speed.

Why Does Light Travel So Slowly?

If you’ve ever wondered why light travels at a very slow rate, then you are not alone. In fact, NASA scientists have produced a series of simple animations to prove the point. The first one shows how long it takes for light to travel around the Earth. The next two are animations that show how long it takes for light to travel from Earth to the moon and from Earth to Mars. In a vacuum, a particle of energy traveling at the speed of sound moves at about 186,282 miles per second, or 670.6 million mph, or 1.079 billion km/h.

Is it Possible for Humans to Ever Travel at Or Near the Speed of Light?

There is an interesting video made by NASA about near-light travel. This demonstrates that we can travel at the speed of light. The time taken to travel from Earth to another planet would be shorter than that of traveling at the speed of light. Furthermore, the earth’s clocks would also continue to move at the standard rate. The possibility of human space travel is exciting.

Why Does the Universe Want to Preserve the Upper Barrier on Speed of Light?

A few years after Einstein’s announcement, French physicist Henri Poincare wrote that matter cannot travel faster than the speed of light. This restriction on particle speeds is even stricter in our Universe, where there are countless unknowns.

What is Faster – The Speed of Light Or the Speed of Darkness?

Light travels at the speed of the sun. However, dark matter should have a slower speed. A shadow moving at the same rate as light moves at the same speed is called a wormhole. If a wormhole exists, then dark matter would move at the same rate as light. If you were to travel through a wormhole, you would get to your destination in a matter of minutes.

What is Stopping Light From Going Any Faster?

It’s impossible to travel faster than light. In fact, the speed of light is infinite, and nothing can go faster than it. This fact is fundamental to the universe, since a particle traveling at the speed of a photon cannot experience time. Also, there’s no mass in light, so nothing can go faster than it. The answer to this question is infinity plus one, which is the speed of the sun.

What is a second measured on a moving clock?

Moving clocks are observed to tick slower, thus a "second" measured on a moving clock is observed to be stretched out or dilated compared to a "second" measured on the observing frame’s clock according to that observing frame. (But take care to not get hung up on semantics.)

How did Maxwell find out that light is an electromagnetic wave?

Maxwell used that fact to calculate, if an electromagnetic wave did exist, which they didn’t know at the time, then that’s the speed that it would have. When people looked at that calculated number, they noticed that it was the same as the measured speed of light. That’s how people found out that light is an electromagnetic wave.

What is the speed of light in an inertial frame?

The point is, light’s speed at any inertial frame is 299792458m/s, so yah.

How long does it take for a sprite to go from zero to c?

It goes from zero to c in zero time.

What is the value of C?

The value of c is a combination of the delay for empty space to respond to a changing electric field (due to the "permittivity of free space") and the delay for empty space to respond to a changing magnetic field (due to the "permeability of free space"). c can be calculated from those other two physical constants.

Is a photon matter or matter?

3) Photons are not matter. They are also not accelerated. A photon always travels at c, end of discussion. It cannot stop, it cannot slow down, it cannot accelerate.

Do photons have mass?

Photons do not have mass. The force they exert on objects they hit is caused by the momentum. Photons do have momentum, but it is not equal to mv like it is for massive particles.

Why does light travel at the same speed?

Ergo, light is made of electromagnetic waves and it travels at that speed, because that is exactly how quickly waves of electricity and magnetism travel through space.

What did Maxwell discover about electromagnetic waves?

Laying the groundwork for what we now understand to be the electromagnetic force, in those equations he discovered that changing electric fields can create magnetic fields, and vice versa. This allows waves of electricity to create waves of magnetism, which go on to make waves of electricity and back and forth and back and forth, leapfrogging over each other, capable of traveling through space.

Why is the speed of light important?

That’s because all massless particles are able to travel at this speed, and since light is massless, it can travel at that speed. And so, the speed of light became an important cornerstone of modern physics.

What did Einstein find about space?

What’s the exchange rate? Einstein found that there was a single constant, a certain speed, that could tell us how much space was equivalent to how much time, and vice versa.

What did Einstein discover about time?

With his special theory of relativity, Einstein realized the true connection between time and space, a unified fabric known as space-time. But as we all know, space is very different than time. A meter or a foot is very different than a second or a year. They appear to be two completely different things.

How fast is light?

We all know and love the speed of light — 299,792,458 meters per second — but why does it have the value that it does? Why isn’t it some other number? And why do we care so much about some random speed of electromagnetic waves? Why did it become such a cornerstone of physics?

What is the fine structure constant?

One such number is known as the fine structure constant, which is a combination of the speed of light, Planck’s constant, and something known as the permittivity of free space.

What happened to the light pulse when Fizeau turned the wheel faster?

What happened? At slow speeds, the light pulse always got back to Fizeau through the same gap in the cog’s teeth. But as Fizeau turned the wheel faster, at a certain speed the pulse was blocked by the following tooth. Knowing the rotational speed, Fizaeau thus could calculate how long it took for light to travel 16 kilometres – and so how fast the light must be travelling. His remarkable result of 315,000 km/s was within about 5% of our most recent measurements using lasers.

How did R?mer explain his observations?

Römer realised his observations could be explained by the varying distance between Jupiter and Io, and Earth. The different times for Io’s orbit reflected the different distances light had to travel. It also allowed Römer to estimate the speed of light as 214,000 km/s. Not bad!

How did Galileo measure the time of the flash?

In 1638 he tried to measure it. He and an assistant perched themselves on distant mountaintops with covered lanterns. The idea was that as soon as Galileo’s assistant saw the flash, he uncovered his lantern. Galileo would then time how long it took to see the return flash. The experiment failed dismally! To succeed, Galileo would have had to register a time difference of microseconds. He had no such time keeping device and his reaction time would be way slower than that.

How fast can nothing travel?

We all know the number one traffic rule of the universe – nothing can travel faster than the speed of light. And that happens to be 299,792.458 kilometres per second. But why is it so?

Who was the first person to measure the speed of light?

The first experimental measurement of the speed of light came 150 years later with Hippolye Fizeau . He came up with an ingenious advance on Galileo’s method. In his experiment, a beam of light was projected onto a rapidly rotating cog-wheel. The teeth of the rotating cog chop the light up into very short pulses. These pulses travelled about 8 kilometres to where Fizeau had positioned a carefully aligned mirror. On the return trip, the reflected light pulse could only reach Fizeau by passing back through one of the gaps in the cog-wheel.

Who discovered that electrons are heavier and heavier?

In 1964, Bill Bertozzi at MIT accelerated electrons to a range of speeds. He then measured their kinetic energy and found that as their speeds approached the speed of light, the electrons became heavier and heavier – until the point they became so heavy it was impossible to make them go any faster. The maximum speed he could get the electrons to travel before they became too heavy to accelerate further? The speed of light.

Who said light is not instantaneous but is extraordinarily rapid?

Undaunted, Galileo concluded that light’s movement, “if not instantaneous, is extraordinarily rapid”.