Whats the equivalent of a "sonic boom" in the terms of light speed?

Question

I know that when an object travels faster than the speed of sound (761 mph), a sonic boom is created. And I know that so far, nothing man made has passed the speed of light (670,616,629.384 miles per hour), but in theory, what would be the likely outcome if something were to travel faster than this speed?

Answer 1

The energy required to accellerate to near light speed is tremendous the closer to the speed of light, the more energy required approaches infinite. Therfore, an object accellerated to the speed of light has become pure energy.

Pretty simple, right. That is, simple in theory.

Back to your sonic boom equivilant. There is none, since the property of sound that carries the "boom" to your ears has no equivilant in the discussion of the propagation of light.

For discussion, however, why not consider red shift and blue shift as the equivilant? You probably are familiar with doppler shift as it applies to sound. A sound is generated at a specific pitch. Put the sound on a moving vehicle. As the vehicle approaches you, at the side of the road, the sound reaches your ears long before the vehicle because sound travels faster than the vehicle. As it nears, the pitcy seems to get higher because the sound waves get compressed. (the wave made a moment before is traveling at the speed of sound, same as the wave made immediatly afterward, but the vehicle is moving forward, compressing the waves closer together) As the vehicle passes, the sound seems to pitch lower, becuse the vehicle is moving away from you, strettching the sound waves farther apart as the sound reaches your ears.

Same thing happens to light. Light moves EXTREMELY fast, so we don't notice any shift in the frequency of light as we travel, even on the fastest jet aircraft. But moving at high speeds, approaching a signifcant percentage of the speed of light, an observer on a space ship might notice that the "white" star they are approaching appears to be reddish, while the star to the rear looks kind of blue. This is the same doppler effect at work. The objects to the front show you a "red shift." They don't really change color, anymore than the sound pitch on the vehicle I mentioned. It only appears to the observer to change.

Does this work for you as an equivilant?

Answer 2

Theoretically, nothing with mass can reach the speed of light because it's mass increases as it's velocity increases. At the speed of light, it's mass would become infinite & therefor would need an infinite amount of energy to accelerate it.

That is based on Relativity as I understand it. The trick is, that physics has a tendancy to breakdown and/or chance when we get to "unusual" limits like this. For a while folks thought it was impossible to break Mach 1 because a seemingly unknown force was pushing harder against the aircraft when it got close. We now know that to be "wave drag", a previously unknown aerodynamic force.

Perhaphs someday we will have a better understanding of what happens when something with mass apporoches light speed. For now, the only valid answer is "we simply don't know".

Oh, one afterthought... Mach 1 is not a fixed speed. Mach is based on a local speed of sound which is based on local air density. Light has been assumed to travel at a constant speed in all inertial reference frames, but new theories are coming to light that say many if not all of the numbers we assume are constant, might in fact be variable... but thats a whole other can of worms.

Answer 3

In a vacuum, you cannot have a "light" boom. However, in materials such as liquids, you DO have light booms. This is called Cherenkov radiation.

How does it work?
In a non-vacuum, the speed of light is decreased from its value in a vacuum. Thus, it IS possible for a particle to travel faster than the speed of light in a material. Cherenkov radiation (blue glow) is a result of particles emanating from nuclear reactions travelling through the cooling liquid or air faster than the speed of light is through the cooling liquid or air. You can see this is certain reactors, there will be a slight blue glow around the fuel rods.

The process is very similar to that of sonic booms. In fact, the equations that relate to the angle of the light shock wave are exactly the same as the one for sound shock waves! These booms are caused when a charged particle passes through and displaces electrons. It is the electromagnetic field of this particle that causes this displacement. As the electrons "fall" back into place, they emit light. However, since the particle is moving so fast, there is not enough time for the charged particles to fall back, thus creating a shock wave.

Cherenkov radiation is commonly used to detect subatomic particles. Scientists have used cherenkov sensors in particle accelerators.

Answer 4

rhsauders is absolutly correct. This was seen in the Appolo missions when cosmic rays entered the cabin. The astronauts saw flashes of light which was the cerenkov radiation. The speed of light in air or a liquid is slower than that in a vacumm. As the cosmic ray (Particle)which was moving faster than the speed of light in that media, "slows" down to a speed which is below what light can travel in that media, the excess energy of the particle is given off as light (flash).

Answer 5

Elementamigo is entirely wrong. Light emitted from a flashlight on a train travels at the speed of light regardless of the speed of train. THAT IS THE BASIS OF THE THEORY OF RELATIVITY! According to said theory, the light from the flashlight on the train travels at exactly the same speed as that from a flashlight standing still on the ground. Since speed is the ratio of distance to time, in order for both flashlight beams to travel at the same speed time must change for the flashlight on the train. Thus, time slows down on the train!

Answer 6

First of all, you cannot go faster than light goes in a vacuum. It isn't just that nothing man made hasn't done it. We haven't seen *anything* do it. Ever. And when we accelerate subatomic particles in our machines to within .0001% of the speed of light, they behave exactly like special relativity predicts. Special relativity also is the one that says that light speed is unattainable.

On the other hand, it *is* possible to go faster than light goes in, say, water. This regularly happens to electrons emitted from radioactive materials at nuclear plants. The resulting shockwave is called Cerenkov radiation and is a beautiful blue in those facilities.

Answer 7

Loads of people have already given you the answer. It is called Cerenkov radiation.
The speed of light IN A VACUUM is an absolute limit bit in a material particles can go faster than light in which case they will emit radiation until they slow down to the local speed of light.

Answer 8

There is actually an example of this: it is called Cerenkov radiation. When atomic particles travel through liquid at faster than the speed of light in the liquid, you get a blue glow which is basically a shock wave.

Answer 9

One thing to be aware of as something increases in velocity it becomes heavier so infact (assuming nothing new has been discovered by physicists since I last looked), you can't reach the speed of light. The reason for this is as you approach it your mass approaches infinite so you wouldnt be able to reach this as your terminal velocity or exceed it.

Basically if you were to travel faster than the speed of light the obvious thing that would happen is you would be on every TV station and in every newspaper for proving conventional physics to be incorrect;-)

Answer 10

According to relativity, you cannot travel faster than the speed of light, as you get closer, the energy required goes higher and higher, so to go the speed of light, you would need an infinite amount of energy.