What happens if you reach light speed

These scattering events are tremendously important in particle physics experiments, as the products of these collisions enable us to reconstruct whatever it is that occurred back at the collision point. Here, a proton beam is shot at a deuterium target in the LUNA experiment.

The rate of nuclear fusion Fixed-target experiments have many applications in particle physics. But the most interesting fact is this: particles that move slower than light in a vacuum, but faster than light in the medium that they enter, are actually breaking the speed of light. This is the one and only real, physical way that particles can exceed the speed of light. And when they do, something fascinating occurs: a special type of radiation — Cherenkov radiation — gets emitted.

Cherenkov was studying radioactive samples that had been prepared, and some of them were being stored in water. The radioactive preparations seemed to emit a faint, bluish-hued light, and even though Cherenkov was studying luminescence — where gamma-rays would excite these solutions, which would then emit visible light when they de-excited — he was quickly able to conclude that this light had a preferred direction. It wasn't a fluorescent phenomenon, but something else entirely.

Today, that same blue glow can be seen in the water tanks surrounding nuclear reactors: Cherenkov radiation. Reactor nuclear experimental RA-6 Republica Argentina 6 , en marcha, showing the characteristic As these particle travel faster than light does in this medium, they emit radiation to shed energy and momentum, which they'll continue to do until they drop below the speed of light.

When you have a very fast particle traveling through a medium, that particle will generally be charged, and the medium itself is made up of positive atomic nuclei and negative electrons charges. The charged particle, as it travels through this medium, has a chance of colliding with one of the particles in there, but since atoms are mostly empty space, the odds of a collision are relatively low over short distances.

Instead, the particle has an effect on the medium that it travels through: it causes the particles in the medium to polarize — where like charges repel and opposite charges attract — in response to the charged particle that's passing through. Once the charged particle is out of the way, however, those electrons return back to their ground state, and those transitions cause the emission of light.

Specifically, they cause the emission of blue light in a cone-like shape, where the geometry of the cone depends on the particle's speed and the speed of light in that particular medium. This animation showcases what happens when a relativistic, charged particle moves faster than light The interactions cause the particle to emit a cone of radiation known as Cherenkov radiation, which is dependent on the speed and energy of the incident particle.

Detecting the properties of this radiation is an enormously useful and widespread technique in experimental particle physics. Neutrinos hardly ever interact with matter at all. However, on the rare occasions that they do, they only impart their energy to one other particle. We can shield it very well from cosmic rays, natural radioactivity, and all sorts of other contaminating sources. And then, we can line the outside of this tank with what are known as photomultiplier tubes: tubes that can detect a single photon, triggering a cascade of electronic reactions enabling us to know where, when, and in what direction a photon came from.

With large enough detectors, we can determine many properties about every neutrino that interacts with a particle in these tanks.

A neutrino event, identifiable by the rings of Cerenkov radiation that show up along the This image shows multiple events, and is part of the suite of experiments paving our way to a greater understanding of neutrinos.

The discovery and understanding of Cherenkov radiation was revolutionary in many ways, but it also led to a frightening application in the early days of laboratory particle physics experiments. A beam of energetic particles leaves no optical signature as it travels through air, but will cause the emission of this blue light if it passes through a medium where it travels faster than light in that medium.

Needless to say, this process was discontinued with the advent of radiation safety training. So, how about I use Alpha Centauri as an example. Lets assume you are able to instantly accelerate to Alpha Centauri is technically 4.

Traveling at Yes, everyone on Earth will have aged four years and you will have aged only 2 weeks. You will have been gone for a total of 9 Earth-years and about 1. Read more about the finicky nature of time here. Care about supporting clean energy adoption? Michelson, along with his colleague Edward Morley, worked under the assumption that light moved as a wave, just like sound.

And just as sound needs particles to move, Michelson and Morley and other physicists of the time reasoned, light must have some kind of medium to move through. This invisible, undetectable stuff was called the "luminiferous aether" also known as "ether".

Though Michelson and Morley built a sophisticated interferometer a very basic version of the instrument used today in LIGO facilities , Michelson could not find evidence of any kind of luminiferous aether whatsoever. Light, he determined, can and does travel through a vacuum.

The equation describes the relationship between mass and energy — small amounts of mass m contain, or are made up of, an inherently enormous amount of energy E. That's what makes nuclear bombs so powerful: They're converting mass into blasts of energy.

Because energy is equal to mass times the speed of light squared, the speed of light serves as a conversion factor, explaining exactly how much energy must be within matter. And because the speed of light is such a huge number, even small amounts of mass must equate to vast quantities of energy. In order to accurately describe the universe, Einstein's elegant equation requires the speed of light to be an immutable constant.

Einstein asserted that light moved through a vacuum, not any kind of luminiferous aether, and in such a way that it moved at the same speed no matter the speed of the observer. Think of it like this: Observers sitting on a train could look at a train moving along a parallel track and think of its relative movement to themselves as zero. But observers moving nearly the speed of light would still perceive light as moving away from themselves at more than million mph. That's because moving really, really fast is one of the only confirmed methods of time travel — time actually slows down for those observers, who will age slower and perceive fewer moments than an observer moving slowly.

In other words, Einstein proposed that the speed of light doesn't vary with the time or place that you measure it, or how fast you yourself are moving. According to the theory, objects with mass cannot ever reach the speed of light. If an object ever did reach the speed of light, its mass would become infinite. And as a result, the energy required to move the object would also become infinite. That means if we base our understanding of physics on special relativity, the speed of light is the immutable speed limit of our universe — the fastest that anything can travel.

Although the speed of light is often referred to as the universe's speed limit, the universe actually expands even faster. The universe expands at a little more than 42 miles 68 kilometers per second for each megaparsec of distance from the observer, wrote astrophysicist Paul Sutter in a previous article for Space. A megaparsec is 3.

Special relativity provides an absolute speed limit within the universe, according to Sutter, but Einstein's theory regarding general relativity allows different behavior when the physics you're examining are no longer "local. That's the domain of general relativity, and general relativity says: Who cares!

That galaxy can have any speed it wants, as long as it stays way far away, and not up next to your face," Sutter wrote. And neither should you. Light in a vacuum is generally held to travel at an absolute speed, but light traveling through any material can be slowed down. The amount that a material slows down light is called its refractive index. Light bends when coming into contact with particles, which results in a decrease in speed, according to an explainer article from the Khan Academy.

Related: Here's what the speed of light looks like in slow motion. For example, light traveling through Earth's atmosphere moves almost as fast as light in a vacuum, slowing down by just three ten-thousandths of the speed of light. Light can be trapped — and even stopped — inside ultra-cold clouds of atoms, according to a study published in the journal Nature. More recently, a study published in the journal Physical Review Letters proposed a new way to stop light in its tracks at "exceptional points," or places where two separate light emissions intersect and merge into one.