Recent content by Nabeshin

Well, for a proton machine where synchrotron losses aren't a big deal yet, conceivably you gain on space. The real issue would be designing a magnet strong enough to get to appreciable energies, which is of course already the limitation in building high energy hadron machines.

The vector in my equation \vec{r}_{12} = ( x_2 - x_1 , y_2 - y_1, z_2 - z_1 ) written out in component form. Similarly the vector \vec{F} = (F_x,F_y, F_z ) . Each component of the left hand side and right hand side are equal, which gives you your three equations. Does that make sense? Can you...

The vector equation for Newtonian gravitation reads: \vec{F}_1 = \frac{G m_1 m_2}{|\vec{r}_{12}|^3} \vec{r}_{12} That is, the force on particle one (in a system of 1 and 2) is directed along the vector connecting it to the second particle ( \vec{r}_{12} ). Given that, what exactly don't you...

In this type of situation, in practice it's not helpful to think of the laser as a stream of photons but rather a classical EM wave. From this point of view, its known as an inverse Free-Electron Laser (in an FEL, energy is transferred from electrons to a laser, so inverse indicates the opposite...

It is thought that this should happen, and in fact is a proposal for how one might generate intermediate mass (10^3<M<10^6 solar) black holes. The idea is called 'Direct Collapse' for black hole formation, if you want to read more about it.

This is one way to look at it. Another way is from the field equation point of view of gravity, a la Gauss' law \vec{\nabla} \cdot \vec{G} = - 4 \pi \rho In one dimension, from this equation a point source simply generates a constant gravitational field (does not vary with distance from the...

Note that generally a physics PhD is AT LEAST a full time job, so it is usually not possible or wise to take on a second job while pursuing it.

I guess the reason for the caveat here may be that a single charged particle is clearly in equilibrium.

Well, this is only because such an inertial 'force' does not act upon a body from any external body (except, perhaps a la Newton, from absolute space). I'm not sure the 3rd law is then applicable to it, although this obviously depends heavily on the particular formulation of this law. I'd prefer...

Keep in mind that aerospace engineering is sufficiently different from a PhD in astrophysics (or just physics, for that matter) that one cannot make the jump without effort. However, a solid grounding in physics (not so much the astro side) can set one up to, with some effort, transition to a...

This is actually quite a subtle point. Which is taken as former, coulomb's law or Gauss'? (From an axiomatic point of view, either works.) If you take coulomb's law to now be 1/r^4, and we're still in our 3D universe, then yes gauss' law in its current form is no good. If you take gauss' law...

Unfortunately the only way for you to be satisfied then is to jump in. We can, and have, studied the environment around black holes (via close stellar orbits and accretion disk phenomena). The only thing 'left' really, is to see gravitational wave signatures from merging black holes, which is...

? This paper seems to be discussing only the coordinate singularities at the horizons, not the physical singularities. It's been obvious for a long time that these are mere coordinate singularities, but the physical singularities cannot be removed by any coordinate transform.

Let me address the original question since the friedmann issue has been cleared up: The EFE do not single out a length scale, hence are 'scale invariant' in that sense. Simply put, gravity on its own knows only about c and G, out of which a length scale cannot be formed. Given matter fields in...

The bit about 'forward' time travel while moving close to the speed of light relative to others is correct (and a confirmed concept in physics). The bit about backwards time travel is speculative at best.