If this were to be concievable, what do you think would happen?

Question

What would happen if a gnat travelling at the speed of light collided head on with a train moving 55 mph. Would there be any impact, damage, etc.?

Answer 1

We already have a serious problem with that in outer space, where micrometeorites travelling at speeds FAR below the speed of light can leave sizeable craters in metal pieces of spacecraft. Now, let's look at some figures. Let's say that the gnat, having a mass of about 10 mg, is travelling at 0.999 the speed of light. Since E = mc² / √(1 - (v/c)²), the energy of the gnat relative to the train is about 2 x 10^13 joules. Now, a train typically weighs in the order of 100 tons, including the engine. The specific heat of steel is very roughly 500,000 joules per ton per degree Kelvin, so that to raise the entire train by one degree Kelvin would require 5 x 10^7 joules. Dividing this into 2 x 10^13 joules gets us about 400,000 degrees Kelvin, which means the entire train will be vaporized into plasma. Forget about the gnat, he's gone too.

As for the idea that it'll just "punch through" the train like a high-speed bullet, when bullets do that, the ejecta matter from the bullet impacts is relatively slow moving. If something close to the speed of light were to "punch through", the ejecta matter would ALSO be travelling very close to the speed of light, which will demolish (and vaporize) the rest of the train in a cascading process. At relativistic speeds, the ejecta matter will be travelling in the FORWARD direction of the original gnat, so it sprays throughout towards the back of the train. This is what, in fact, happens in particle accelerator collisions, when the target is fixed.

Answer 2

The gnat would probably make a pinhead sized hole that grew wider all the way down through the entire length of the train. Since this hole is so tiny it probably would not cause any noticeable damage immediately, except where the gnat went through steam pipes or hydraulic lines, and of course, people. The hole at the front of the train would probably be fairly neat and well-defined, but as the gnat slammed through each successive layer of material it would become more and more deformed and splattered, until by the time it reached the caboose, the gnat might be flattened to the size of a basketball and blow out of the back of the train like an explosion.

The possibility also exists that since the gnat is traveling at the speed of light that each atom of the gnat would weigh as much as the entire earth, so the gnat would not flatten or deform at all, and simply punch a tiny hole instantaneously from the cowcatcher to the caboose.

Answer 3

The gnat would punch a neat hole through every wall it encounters in the train. When something moves faster than the speed of sound in the material, the material spontaneously yields, while leaving the surrounding material relatively undamaged.

Such is the case when tank armor is attacked by explosively formed penetrators. The incident hole in the armor is surprisingly small.:
http://en.wikipedia.org/wiki/Explosively_Formed_Penetrator

That's assuming that the massive gravitational anomaly that moves with the gnat doesn't simply collapse the train to begin with.

Answer 4

The train would be destroyed and the fly wouldn't be affected at all. This is because the fly would have an infinite mass if it could travel the speed of light (which is part of the reason why it's impossible). Because of the infinite mass, its momentum would be infinite and it would absolutely demolish the train. It wouldn't be a pretty sight.

Answer 5

I would assume there would be a great deal of damage/impact.....think about the momentum....a gnat may not be very massive, but at such a high velocity, the little bit of mass is greatly amplified....so yeah...its gonna hurt

Answer 6

travelling at the speed of light, the gnat would have almost infinite mass.

That makes for a very messy collission

Answer 7

particular, at the beginning, each little thing that has a beginning up ,has an end. which could in all probability advise that earth,our solar , and so on will could end sometime.yet that does no longer mean that the full universe has to end. nicely i do no longer think of the international is going to end on Dec.21 2012. theory possibly Mayans did no longer have adequate space left to make a calendar previous it.(lol) so be satisfied ! the thought-approximately loss of life is greater devastating than loss of life itself and attempt to stay in the present.

Answer 8

the damage would be to the gnat....... it wouldn't have the guts to do that again...........