Recent content by jshuford

O.k., I'm not sure how to phrase this, but I'm going to try. If I'm confusing in my question, just ask for a clarification. I want to know how detecting the source (or direction) of an interstellar signal works? Specifically, a theoretical signal sent from an alien civilization at us. For...

I've told people before and I'll tell you. https://www.amazon.com/dp/0553380168/?tag=pfamazon01-20 (both the book and the TV miniseries), by Carl Sagan is another classic layman physics intro, though it's getting a little dated by now. It's also geared to a slightly younger crowd, so if you're...

Gmax137, I disagreed with you in my above response, but I wanted to elaborate on my disagreement more directly with you to give you a chance to respond if you want. So first, let's establish our terms. Space is simply that which things exist in. Like I said in my above post, in our universe...

This is getting picky with definitions, but basically yes. A vacuum is defined by an area of space that is free of matter. A vacuum may, and inevitably does, contain energy however. Energy does not need matter to exist. As for the term "empty space", this gets into the vagaries of the term...

I believe he means a torch in the British sense, which is known to Americans as a Flashlight.

Plus, aren't neutrinos mass-less particles anyway?

No, light does not have mass. The particle of light, the photon, is mass-less. However, it is still affected by gravity. I assume you mean at one time. That's a tricky question. I'm going to go with infinite though. Someone might correct me on this one though. Since waves have no mass...

Twice as far as what? That seems to imply to me that signal strength decreases quickly over distance, but don't we detect signals over interstellar distances?

A Solar Sail/Solar Parachute could use the drag produced by moving towards the sun by "catching" photons with a big non-reflective parachute. However, the problem is that the sail would need to be hundreds, or even thousands of square kilometers to be effective. Also, it probably wound never...

Someone might correct me but here's my take, and I'm pretty sure on this: The motion is relative to whatever you want. So the motion of a spinning top is relative to the "stationary" table it sits on, you as an observer, the Earth, and everything else, based on each things particular velocity...

Most of the energy would remain as photons bouncing between the mirrors, but it would loose a bit of energy every bounce-cycle to heat so the system would run out eventually. In fact, it would run out exactly when you lost 100% of the energy you put in as heat. Also, unless the mirror is...

I don't know for sure, but I imagine it's lost as heat via infrared waves.

Ah, that actually helps a lot. I thought it might be some fundamental difference between waves that require a solid medium and waves that can travel in a vacuum. That gives me a lot of new stuff to look up though. :) So why do waves that don't need a medium degrade over distance? Like a...

This may be a very dumb question, but I was wondering, does amplitude function as a measurement for "strength" for a radio signal (by strength I mean the ability of one wave to dominate another on a receiver)? I know that hertz defines the frequency, which I understand as the part of the...