Tag Info

New answers tagged

0

I think one has to be very careful when talking about "particles popping in and out of existence". This interpretation is only sort of fine in flat-spacetime QFT, where the Minkowski metric is time-invariant, so has a global timeline Killing vector. The definition of a particle depends on the notion of there existing time invariance! Since black hole ...


2

Energy and momentum are conserved at every vertex of a Feynman diagram in quantum field theory. No internal lines in a Feynman diagram associated with a virtual particles violate energy-momentum conservation. It is true, however, that virtual particles are off-shell, that is, they do not satisfy the ordinary equations of motion, such as $$E^2=p^2 + m^2.$$ ...


0

Let us assume that the volume of the heavier fluid remains constant (as we always do), and that the drilling pipe and the accompanying setup is vertical. In the absence of the packer, buoyant forces would take over and push up on your pump. But in the presence of your packer, the heavier fluid is restricted from creating vacuum under the packer due to the ...


0

It Possible to have it work. But it's not feasible to keep it working. The equation is simply Bernoulli's Principle/equation. Very basics; -Venturi needs a rise in a velocity and a drop in a Pressure. -There is no negative pressure, so you end up having vacuum really easily with just 10% pressure left. Why is this a problem? The exit side of venturi is ...


3

The physical absurdity - or at least highly hyperbolic situations - of most of Roald Dahl's scenarios is the essential Dahl - it's wholesale a part of his humor and his lack compliance with physical laws is, in this respect, quite deliberate. Having said this, the "Great Big Greedy Nincompoop" disappearing up the tube is wholly possible, given the right ...


0

Will the humidity of the air inside the bell change or remain the same? Assuming there is no change in temperature, the relative humidity will decrease. If it changes, that would seem to suggest that for some reason the water molecules are preferentially being sucked out by the vacuum pump. Why would that be? You may have a misunderstanding of ...


1

As Mark Eichenlaub's Answer states, this is a quote from one of Carrol's admired forerunners. You actually hit nearer the mark with your own words: So, in physics void can mean anything but "void". In modern physics there are only quantum fields, a handful of them: the photon field, electron/ positron field, quark field, gluon field and so forth. In ...


-1

Look at H, the simplest atom. One neutron and one electron. If your imagination can put H in perspective, it would be the Empire State Building as the nucleus and a grapefruit racing around it at 500 yards. This model is composed mostly of SPACE or VOID!!


8

I think the problem in understanding this is the idea of "space being sucked into a black hole." The reality is matter is "sucked" into a black hole. Space is warped around the black whole, but space is not "sucked" into anything. Here's the issue. What is space? You can't touch space (or better, the space-time continuum). So, one view is that space is ...


0

Electromagnetic waves are only an observed phenomenon. There is no travel. As an example we can choose a photon which is "traveling" from Sun to Earth (for simplicity we do not care about gravity issues here). That means that Sun is emitting a bit of energy (a momentum) which is received by Earth. So far everything is OK. But what is happening between ...


0

Since, electro magnetic waves have electric and magnetic vector. Due to this EM waves show electric and magnetic field. An electric and magnetic field have no need a medium to show thier effect. Hence in the presence of electric and magnetic field vector which vibrate perpendeculer to each other and get pertervation EM waves travels in vacuum.



Top 50 recent answers are included