Recent content by Everett

I think that an important issue that is often ignored with opportunity cost is inflation, the decrease in the value of a denomination over time. Basically, it means that for a loan, you will be paying with dollars/euros that are less valuable than the ones you borrowed at the initiation of the...

Sparky968, Actually, the gap between the Earth and the Moon is slowly increasing. A few hundred million years ago the Moon was a lot closer to the Earth than it is now, and months were a lot shorter. For the Earth/Moon system, the angular momentun of the Earth's rotation about its axis is...

TheShapeofTime, If I am reading you, then you are asking if light is like a disturbance of some pervasive electromagnetic field, like dropping a rock into a pond of water creates waves on the surface of the pond. About a century ago, people were debating if light traveled through the...

Different colors of light, same as different frequencies of light, or different wavelengths, travel at different speeds through a transparent medium like air. You are correct, the different colors disperse/refract differently. For prisms: Blue bends best, red refracts rotten!

Here is a link to an old report on Electron Cyclotron Resonance (ECR) ion sources. These are used to produce high charge state ions for accelerators like cyclotrons or linacs. http://ecrgroup.lbl.gov/papers_pdf/rsi00625.pdf Take a look at Table 1. You can see that they managed to fully ionize...

If it could exist, then a negative mass would act as you describe. With mass negative, then acceleration would be in the opposite direction from an applied force. Example: Take two particles at rest, one with a unit of positive mass and the other with a unit of negative mass. Place a...

Here is another way to look at this. In the relevant diagram at the URL you give, the sail diverts solar flux 90 degrees so that it is directed along the direction of motion of the satellite. Diverting the solar flux requires an exchange of momentum; there is a force on the satellite where the...

I disagree with the statement about EM fields not causing friction, or at least some force very much like it. Magnetic fields in space will induce eddy currents in conductors (plasmas, iron-nickel meteors, cores of planets) moving across the field lines. Creating eddy currents will slow down...

This is like the stereotypical ice sk8er problem, but instead of arms and legs moving in toward the center, is it not(X and Y)

All the lasers I know about have some sort of laser cavity where the photons make many circuits (n) between reflective ends. The effective geometry has the photons that do not exit out of the sides of the cavity traveling a distance of n times the length of the cavity before exiting the laser...