# Hydrogen atom to 90% the speed of light

1. Jul 31, 2011

I do not understand if you accelerate a hydrogen atom to 90% the speed of light its mass is greatly increased. Are the forces that hold it together increased? If not how is it different, will it fall apart? If the forces are increased in relationship to the mass of the atom the energy released using those forces should be increased.Could particle accelerator guys see any sign of this.

2. Jul 31, 2011

### Staff: Mentor

Remember that velocity is relative. We can also get a relative velocity of 0.9c between the hydrogen atom and you, by accelerating you to 0.9c, and the result must be the same, by the Principle of Relativity.

Under this scenario, the hydrogen atom is simply sitting there, minding its own business. Why should it decide to fall apart, simply because you are zooming past it at 0.9c?

3. Jul 31, 2011

Trying to understand in are imaginary space ship as it accelerates the mass increases because it increases it becomes harder to accelerate but acceleration comes from the mass of the reactance there mass has increased also. So the thrust should not be affected

Last edited: Jul 31, 2011
4. Jul 31, 2011

### BruceW

These kinds of questions will become clear after learning relativity for yourself. (Hope I don't sound mean, but its true).

If we're talking about free particles, then from its reference frame, everything is normal, so it won't fall apart or anything.
And from the perspective of the human in the lab, time dilation and length contraction will affect things like the decay rate of the particle. Also, the energy of the particle will be given by the equation for relativistic energy.

Do you mean 'trying to understand what happens to a hypothetical space ship..."?
As viewed from some other inertial frame, yes the relativistic mass of the propellant will increase as the rocket speeds up, and yes the acceleration per force applied will be less at high speed. But your last sentence is not justified. You would need to analyse the problem using relativity to find out what happens, but it certainly won't be the same as the newtonian case when its speed approaches c.

5. Aug 1, 2011

### rationalist76

So atoms do not destabilize as a result of velocity? (i know i may sound stupid, just learning about Relativity and that good stuff)

6. Aug 2, 2011

### ZikZak

No, atoms don't destabilize as a result of velocity. *Nothing* happens as a result of velocity. The reason it's called "Relativity" is that velocity is relative: there is no such thing as your "true" or "absolute" velocity, only the relative velocities between you and other bodies. Meaning that physics is the same, no matter what other observers might measure your velocity to be. If atoms don't destabilize in your lab "at rest," then they won't destabilize in a lab on board a spaceship traveling at nearly c either. No experiment will return a different result on the spaceship.

If an experiment existed whose result changed, depending on merely the velocity of the laboratory, then you could perform that experiment to derive an absolute speed through space, and the point of Relativity is that there is no such thing.

7. Aug 2, 2011

### ZapperZ

Staff Emeritus
Just think. According to some alien in another galaxy, you are moving very, very fast. Do you see yourself destabilizing?

Zz.

8. Aug 2, 2011

### rationalist76

No. Yet the alien will perceive it that way, correct?

9. Aug 2, 2011

### DaveC426913

Perceive what? Certainly he'll see you moving very fast relative to him.

The point here is that his seeing you move very fast doesn't mean you start feeling excessive forces or starting to fall apart.

relativity essentially means you are stationary; it is the rest of the universe that is moving relative to you.