140,615 reputation
9242395
bio website ratsauce.co.uk
location Chester, United Kingdom
age 54
visits member for 4 years, 5 months
seen 1 hour ago

Semi retired old time computer nerd who started programming on a Commodore Pet.

Since I'm also active in the Physics forum I should add that I started as a theoretical chemist, moved into solid state photochemistry and finally worked in industry as a colloid scientist. I only became a full time computer nerd in 1997.


Jun
22
comment What's the significance of neutrino oscillations?
See the question I've linked - the oscillations imply neutrinos have a mass. For more on the subject search this site.
Jun
21
comment Bending of light in gravity. Dark Matter, Dark Energy
I'm voting to close this question as off-topic because there is no outside and the centre of gravity is everywhere
Jun
21
comment How does an electron deexcites during stimulated emission?
The question I've linked asks: Can someone explain the reason why the incoming photon stimulates the atom to emit a second one? To me it seemed more logic for the atom to absorb the photon and go an energy level up. So it's an exact duplicate of yours.
Jun
21
comment How does an electron deexcites during stimulated emission?
possible duplicate of Atomic Physics: stimulated emission
Jun
20
comment Is it possible to make a low dense object sink in a fluid of higher density by cutting the object in particular shapes?
@Angelika: Yes.
Jun
20
comment Why don't electrons crash into the nuclei they “orbit”?
This does not provide an answer to the question. To critique or request clarification from an author, leave a comment below their post.
Jun
19
comment Particle position and speed
possible duplicate of Is the wave-particle duality a real duality?
Jun
19
comment How long would it take me to travel to a distant star?
@PyRulez: SR and GR use exactly the same maths for this type of calculation (not surprising as SR is a subset of GR). The only difference in GR is that the metric you need to work with is more complicated.
Jun
19
comment Quantum entanglement and the big bang
The Big Bang didn't happen at a point.
Jun
19
comment Galilean relativity & the road to special relativity
Newton introduced an absolute time, that all observers would agree on, however nothing in Newton's work requires an absolute space. Newton understood full well that positions and velocities were relative - after all, he was familiar with Galileo's work. I don't understand your last paragraph. What exactly are you asking? Actually I'm not what the first part of your question is asking either.
Jun
19
comment Free neutrons in the sun's core?
Hi Anna, I'm not sure this answers the question. As long as the neutron lifeime is not zero there should be a non-zero equilibrium density of neutrons. Rob is asking what this concentration is.
Jun
19
comment Newton's first law of motion a corollary of second law?
possible duplicate of Why is Newton's first law necessary?
Jun
19
comment Is the fourth dimension of Minkowski Spacetime viewed as an axis?
Hi Kimmy. The question I've linked may not appear a duplicate at first sight, but I think it does answer your question. You are making the common mistake of confusing the time coordinate with the flow of time.
Jun
18
comment Will increased weight slow a pendulum?
@Hennes: yes, but changing the weight will change the amplitude of the swing, which is what I think Reid is getting at.
Jun
18
comment Why Fermi level doesn't change with temperature?
Ian, that's the Fermi energy you're describing. The Fermi level is the 50% occupation energy. The two are the same at absolute zero but different at any temperature greater than absolute zero. Having said that, I've seen the term Fermi energy and Fermi level used interchangeably, though they shouldn't be.
Jun
18
comment Deriving escape velocity using centripetal force
@user1163511: but leaving aside the infinite plane (as it's a rather special case) it doesn't matter what shape the gravitating body is. The kinetic energy is not dependant on the direction of motion and the only requirement is K = -V. So the object will still escape no matter what direction it's moving in.
Jun
18
comment Deriving escape velocity using centripetal force
@user1163511: The infinite flat plane is one of those exercises we give to students. In this case the gravitational acceleration is independant of distance from the plane so there is no escape velocity - to escape to infinity would require infinite energy.
Jun
18
comment Deriving escape velocity using centripetal force
@user1163511: no! The perpendicular component of the velocity can be zero or even negative and the object will still escape. Suppose the object starts moving tangential to the surface, so the perpendicular component is zero. Because $v$ is greater than the orbital velocity (twice as great in fact) the object starts accelerating outwards and moves outwards (to infinity) in a spiral trajectory.
Jun
18
comment Deriving escape velocity using centripetal force
The object doesn't have to be moving perpendicular to the surface. The kinetic energy is the same no matter which way the object is moving. If it's moving sideways it will still escape but the trajectory will be a spiral instead of a straight line outwards.
Jun
18
comment Capillary effect to pump water up to cool water
@KyleKanos: I've added a link