Are light speed objects visible?

zenbabelfish

autonomous hyperreal sophist
Registered Senior Member
Would an object exceeding the speed of light be visible to the human eye? If it were not how could it be detected?
 
Thanks for your reply, James.
Can anything exceed the speed of light?

Well, apart from the hypothetical tachyon as mentioned, nothing with mass.

Photons can be made to exceed C in certain circumstances, iirc an experiment to pass photons between two metal plates, x-ray lithographed with lines forced the photon to accelerate, something about the 'frequency' (from E=Hf) of the photon and the spacing of the lines... although my memory is fuzzy, and I bet I don't have the relevant edition of 'New Scientist' I read it in anymore, ... I'll look for a reference. The effect is probably very small, and unobservable, and Heisenberg will almost certainly mop up any nasty causality threating implications anyway.
 
So I guess this rules out dark matter (existing at or above the speed of light) due to its mass?
 
Can anything exceed the speed of light?

Yes, but not anything with mass. If you take a wave, for example, it can have what is known as a "phase velocity" that is faster than the speed of light, and there's no problem with that.

A good rule of thumb is that nothing that does or could carry information, like a message, can travel faster than the speed of light.
 
Thanks James R - this gives a good start point to develop further understanding.
 
Hi Zen---

There are things that could excede the speed of light, but they could not carry information, like James said.

My favorite example is to take an arbitrarily bright flashlight and shine it on a wall arbitrarily far away. Now let a bug go across the light. The bug's shadow can go across the light faster than the speed of light.

It would be interesting to think what one would see though.
 
Good analogy Ben...something I can really visualise. We have a big problem here in the UK with fewer people interested in physics (and science in general) and teaching it....bit of a knowledge gap developing. Everyone wants be in the media.
The ability to communicate complex phenomena in metaphor or analogy is a great asset in engaging people with meaningful science.
 
One good reason why we can't accelerate any significant mass to the speed of light is because if it hits anything, like air, it will explode like an atomic bomb. We may never know if a heavier object can travel faster than a photon or an atom.
 
We have a big problem here in the UK with fewer people interested in physics

Plus there's aparently a pretty big brain drain, from what a friend of mine told me. He said everybody there (it was his experience, at least) just wants to get out of the Isles, on account of the weather and the pay. (He got his degree from Leicester and worked for the MOD before coming to America to get his PhD.)
 
One good reason why we can't accelerate any significant mass to the speed of light is because if it hits anything, like air, it will explode like an atomic bomb.

Er, not really, the reason is that as an object approaches C it's mass increases according to the formula;

m = m0/((1 - v^2/c^2))^1/2

Not because we are worried about collisions.

We may never know if a heavier object can travel faster than a photon or an atom.

Er, yes we do, 'a heavier object' can't move faster than a photon. I don't know why you added 'atom', it being a 'heavier object' wrt photons.
 
So, in a hypothetical laboratory, if helium was drawn into a black hole would the structural ionic information degrade so the helium became hydrogen as it drew closer to the event horizon?
 
This is funny. Fiction accepted as fact by the very people that state that they always go after facts.

Light is no barrier. You can shoot right past it and a whole lot faster. In a world were everything is moving, there is no zero point on which to base the speed of light but from where we stand and watch it.

I am sure this post will go head long into people that will just look at me as a jerk and probably worse. Making a statment that is unfounded and god knows what elss. But like the people that said the Earth was round and got put down for it, I think the criticism is acceptable in the face of whats real. No amount of chichen scratches from "experts" will change the fact the you can go right upto and past the speed of light, all without the slightest change in the elapsing of time.

Don't get me all wrong. I never said the E=MC2 formual was worthless. It was just over assumed what implications it would have on objects that reach and exceed the speed of light. The threary of relativety is not something I despute, just that light speed is the pinicale it was made out to be. Perhaps its the wrong point of relativaty. Lets not forget that it is a theary and will need some modifications as our perception grows.

And we can make space ships that can safely go faster than light. It would need redesigning and a whole lot of power and etc, but it can be done. However, thank you for pointing out that its not safe to do it in any of ours at this time. I would guess it would be much like taking a wooden biplane and pushing it to moch 3.

But the above was not the question that started the post. It was if objects could be seen that traveled at the speed of light. I would have to say it would be tough sence most people have trouble seeing quick flashes. We know sound is not going to help at mach 1 for oncoming objects. I can't say what it would look like for light speed objects but I imagine there would be a problem.
 
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And we can make space ships that can safely go faster than light. It would need redesigning and a whole lot of power and etc, but it can be done.

You sound awful confident in these statements. How can you get around the bounds on Lorentz violation?
 
Lorentz violation? Lorentz symmetry is not an issue. I can leave it up to others to reconnect the dots of Lorentz symmetry if they care to. I am not saying everything is the same at high speeds as it is at low speeds. Yes there are things to worry about. But not all thearies are the best destripion for real word events. I will not tell you that I am an expert on all variables of plane flight, much less light speeds in areas of the universe I have yet to see and what could be found there.

However, provided you don't fly into a rock it would be safer. I can't say much for running into large objects at these speeds but armor can do alot more then we make it do. Also you would need to have a fast sensor (infrared would work well for this) but you could look ahead and turn the ship before colliding with large objects. (I never said you could be slouchy at these speeds). For smaller objects, simple fields with the right charge could get the object moving before you colide with it if not get it out of the way all together, that would make it very survivable as it would lose it's collision momentum with you. Lets not forget how small of a force it would take to get it moving in the vacuum of space. Even if it did go "clang" it could hit a slanted surface (for example the ship as a arrow shape) that would further reduce the danger.

Another thing I was thinking could be a problem (but remember this is just a guess) is that as you exceed the speed of light, you could end up compacting photos on the outside of your ship. This could create a plasma buildup that is, well... hot and dangerous. Aerodynamics could let it slip over and by safely. Cooling could cut down on the heating effects.
 
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Er, not really, the reason is that as an object approaches C it's mass increases according to the formula;

m = m0/((1 - v^2/c^2))^1/2

Not because we are worried about collisions.

That doesn't even make sense. The more its mass increases, the worse the explosion if the projectile collides with something.


Er, yes we do, 'a heavier object' can't move faster than a photon. I don't know why you added 'atom', it being a 'heavier object' wrt photons.

Because we do accelerate atoms to very close to the speed of light. I've suspected for a while that an object containing many atoms, like a slug of iron weighing a gram or so, might be able to travel faster than the speed of light. If we have such a thing as a "Higgs field" that limits the speed that an atom can be accelerated to, then a heavier object may have a greater terminal velocity, having a much greater ratio of mass over cross section.
 
That doesn't even make sense. The more its mass increases, the worse the explosion if the projectile collides with something.

It makes perfect sense, it's the Lorentz transformation for mass as an object approaches the speed of light. Basically, the closer you get to the speed of light, the more your mass increases, exponentially. It requires more and more energy to accelerate, making it impossible for an object with mass to achieve light speed.


Because we do accelerate atoms to very close to the speed of light.

Close, but not to the speed of light, and then what do we do? We smash them into targets! the very collision you say is problematic, is performed many many times in experiments!

I've suspected for a while that an object containing many atoms, like a slug of iron weighing a gram or so, might be able to travel faster than the speed of light.

You obviously don't understand how a particle accelerator works. It works on charged particles, accelerated by magnetic fields. A solid, chargeless mass could not be accelerated this way. Even it it could, that Lorentz transformation still holds, and it could not achieve, let alone exceed, the speed of light.

If we have such a thing as a "Higgs field" that limits the speed that an atom can be accelerated to, then a heavier object may have a greater terminal velocity, having a much greater ratio of mass over cross section.

Utter tosh. Pseudoscienific bunkem. 'A heavier object'? Your 'slug of lead' is comprised of regular atoms, nothing more, and the rules of physics apply to every atom, and the whole, equally. If you can't accelerate a single particle to light speed, you cant accelerate anything bigger!
 
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